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High-speed Machining of Inconel 718 with Ceramic Tools
Abstract
High speed machining for Inconel 718 was carried out with SiC whisker reinforced alumina, silicon nitride and TiC added alumina ceramic tools. In this test, not only the commercial available inserts, square type 120408 or button type 120400, but also specially designed cutting edges were tried. The SiC whisker tool showed the best performance in respect of notch wear at the cutting speed of under 300m/min. However, when the speed exceed -400m/min., the TiC added alumina ceramic tool showed the smallest wear compare to other tools. Specially designed cutting edge made the notch wear small.
... CC670 exhibited better wear resistance which was attributed to the fact that a magnesium compound layer was formed on the tool which acted as a protective coating. Machining of Inconel 718 at very high velocities was investigated by Narutaki et al. [67] wherein SiC whisker tool was used which showed the best performance with respect to notch wear. Above speeds of 400 m/min, slight wear was noticed and it was significantly less compared to the wear caused in other tools. ...
... A 15 clearance angle along with a high negative rake angle of À15 increased the tool life significantly. Alloy 718 machining at high velocities was investigated using silicon carbide whisker reinforced alumina, silicon nitride and titanium carbide added alumina ceramic tools [67]. Custom designed edges for the tools were compared along with the commercially available inserts and the results were reported. ...
... Cluster 6 Richards and Aspinwall [213] Tian and Shin [214] Schulz [215] Skvarenina and Shin [216] Narutaki et al. [67] Novak et al. [217] Gatto and Iuliano [113] Rozzi [218] Dewes and Aspinwall [219] Rozzi et al. [220] Brandt et al. [66] Leshock et al. [221] Balazinski et al. [222] Chryssolouris et al. [223] Alauddin et al. [224] Pfefferkorn et al. [225] Alauddin et al. [226] Lei et al. [227] Kuzucu et al. [228] Ding and Shin [229] measured in the process. It was reported that the cutting speed did not influence the cutting forces and in symmetric face milling the force component in the z-direction is the highest. ...
This article presents a detailed systematic review on the current developments in the machining of superalloys. Superalloys have extensive high temperature applications and research has been conducted in various machining processes. The conventional and nonconventional processing of superalloys is an emerging research area and needs attention. This systematic literature survey intends to consolidate, review, and critically highlight the machining aspects carried out in this field. Bibliometric analysis using BibExcel is conducted to capture new insights in the focused field of research. Articles published since 1991 on material processing of superalloys are listed and referenced. Article statistics on each class of publications have been highlighted. A citation analysis is also reported and the articles with the highest impact are identified. Geographical mapping reveals the role of universities and institutions in the focused research. Gephi is used to identify the key research clusters and topics. Seven prominent clusters were identified and articles in each research cluster have been elaborated. A quality versus quantity analysis of the various publications is done. Present state of art in the focused research and the future directions on the material processing of superal-loys based on the review are reported.
... [92] The potential to develop a cleaner and healthier work environment (having less mist in the air) is the primary advantage. Abd Rahim et al. [93] studied the performance of synthetic ester and palm oil (vegetable oil) with MQL cooling conditions while drilling of [70] 2 Aged Inconel 718 PVD multilayer carbide insert K-type thermocouple Temperature gradient 650ºC for a depth of 0.5 mm at machining velocity of 320 m/min [71] 3 Inconel 718 SiAlON ceramic tool Thermal infrared camera The maximum cutting-edge temperature as 1200-1250ºC was noticed [72] 4 Inconel 718 SiAlON ceramic tool Infrared thermal imaging system Above 850ºC cutting temperature was reported [73] 5 Aged Inconel 718 Coated carbide Thermo couple method At cutting temperature 650ºC, the flank wear obtained is minimum [74] 6 Inconel 718 PVD TiAlN coated carbide insert Thermo couple method The maximum cutting temperatures developed under dry machining as around 410ºC [75] 7 Inconel 718 alloy Electroplated CBN grinding wheel Semiartificial thermocouple technique ...
... It has resulted due to the generation of high temperatures. In the subject context, the performance of the cutting fluid is enhanced by supplying the fluid medium at high pressure (70,150,300, and 450 bar). The enhancement in cutting fluid pressure from 70 to 150 bar, resulted in improved tool life. ...
... Researchers have observed a temperature rise in the range of 800-1200°C [146][147][148] while machining Inconel 718 with a cutting velocity of 10-50 m/min and it increases up to 1300°C with a further rise in cutting velocity (400-500 m/min). [70] These severe conditions may cause adhesion of chip to the work material and the cutting tool (promoting wear and softening of the cutting tool), thereby the tool life and surface integrity (of the machined surface) are affected. Kaynak [149] compared the machining performance of dry and MQL machining with cryogenic assisted machining on Inconel 718. ...
The demand for high temperature-resistant superalloys such as Inconel 718 is increasing rapidly, as they possess superior mechanical, chemical, and physical properties. Hence, these materials are highly adaptable for aerospace, nuclear, and marine applications. Nonetheless, during machining of such alloys, high temperatures develop at the interface region. It accelerates the tool wear and adversely affects the integrity of the prepared surfaces. Although conventional metalworking fluids are competent in normalizing/limiting the cutting-edge temperature, the environmental obligations and health issues to the workers have forced the manufacturing industry to move towards environment-friendly machining process, viz. dry machining. High-speed machining of Inconel 718 (under dry condition) can lead to the attainment of high cutting temperatures, thereby activating the mechanisms of built-up-edge (BUE) development and diffusion, leading to enhanced wear rate of tool. Besides, high temperatures can alter the integrity, infuse residual stresses, and promote crack generation/propagation on the processed surface. Therefore, the present paper contributes a detailed insight into heat generation during machining of Inconel 718 and its influence on various machining responses. Additionally, the work addresses multiple possibilities to reduce the cutting temperature with due emphasis on distinct machining methodologies, viz. dry, wet, and tool texturing.
Abbreviations: BUE: Built-up Edge; AISI: American Iron and Steel Institute; AJM: Abrasive Jet Machining; AlTiN: Aluminium Titanium Nitride; Al2O3: Aluminum Oxide or Alumina; Al2O3/SiC: SiC whisker-reinforced alumina Al2O3 ceramic; Al2O3-TiC: TiC added alumina ceramic; AS: Conventional tool; AT-PA: Parallel grooves; AT-PE: Perpendicular grooves; AT-W: Wavy pattern; CaF2: Calcium fluoride; CBN: Cubic boron nitride; CBN-OR: Perpendicular to cutting edge; CBN-ORE : Perpendicular grooves 30 µm away from main cutting edge; CBN-PA: Parallel to cutting edge; CFT: Nano textured tool; CFT WS: Nano textured with soft coated WS2; CrN: Chromium Nitride; CT: Conventional cutting tool; DOC notch wear: Depth-of-cut notch wear; EBSD: Electron back scatter diffraction; ECM: Electrochemical machining; FCC: Face centered cubic; GWP: Global warming potential; HPC: High-pressure cooling; HPJ: High-pressure jet; HPJA: High-pressure jet assistance; HRSA: Heat-resisted super alloy; HSS: High-speed steel; IPF: Inverse pole figure; ISO: International organization for standardization; l/h: liter/hour; L/min: Liter/minute; Micro-EDM: Micro-electrical machining; MoS2: Molybdenum disulfide; MQL: Minimum quantity lubrication; MWFs: Metal-working fluids; NIOSH: National Institute of Occupational Safety and Health; PCBN: Polycrystalline Cubic Boron Nitride; PVD: Physical vapor deposition; SEM: Scanning electron microscope; Si3N4: Silicon nitride; ST: Graphite soft-coated tool; STT-F: Linear grooves on the flank surface; STT-R: Elliptical textures on the rake face; STT-0: Plain WC/Co carbide tool; STT-1: Elliptical grooves; STT-2: Parallel grooves; STT-3: Perpendicular grooves; TiAlN: Titanium Aluminium Nitride; TiCN: Titanium Carbonitride; TiN: Titanium Nitride; T-IPA: Perpendicular textures to chip flow; T-IPE: Parallel textures to the chip flow; T-PA: Texture surfaces inclined an angle to the chip flow; TT: Textured tool under dry condition; TT+SL: Textured tool under solid lubricant-assisted MQL cooling conditions; T1: Un-textured tool; T2: Texture tool having circular pit holes; T3: Hybrid texture tool combination of circular pit holes and linear grooves; TT: Textured inserts; TT: WS2-soft-coated WS2 textured tool; T1: Conventional insert; T2: Conical dimple-textured tool; T3: Square dimple-shaped insert; T4: Scratches provided on the cutting insert; T-1: Untextured insert; T-2: Pit holes textured insert; T-3: Hybrid textured insert; US: United States; USM: Ultrasonic Machining; WC: Tungsten carbide; WC–Co: Tungsten carbide-cobalt; WEDM: Wire electrical discharge machining; WS2: Tungsten disulfide
... At cutting speeds of 200-400 and 400-700 m/min, the notch wear and the trailed edge wear were the major wear patterns, respectively, in milling of Inconel 718 by a whisker-reinforced ceramic tool [82]. A SiC whisker tool delivered the best notch wear resistance at 100-300 m/min cutting speed, and a TiC added Al 2 O 3 -based ceramic tool showed better wear resistance at 500 m/min cutting speed [83]. In addition, oxygen-and argon-rich atmospheres slowed/suppressed significantly notch wear of a SiAlON ceramic tool, regardless of tool geometry and cutting speed. ...
... Round shape inserts of a whisker-reinforced ceramic provided better performance compared with square ones in a milling experiment of Inconel 718 [82]. In another experiment [83], the less notch wear on the end flank face was found, as well as a lower thrust force, as shown in Fig. 8. Bigger contact radius of a SiC whiskerreinforced Al 2 O 3 ceramic tool provided a lower surface roughness under HPC in the machining of Inconel 718 [90]; however, the coolant accelerating notch wear on both flank and rake faces was observed. ...
... A low CBN content between 45 and 60% of a cutting tool with a ceramic binder showed better wear resistance in a turning experiment of Inconel 718 [94]. However, sometimes, the influence of CBN content on tool wear is also [83] related to the types of Ni-based superalloys. In another turning experiment of superalloys GH706 (39-44% Ni), the highest CBN content tool with metal binder showed the best tool wear resistance within five types of PCBN materials with different CBN contents and binders. ...
In this paper, a state-of-the-art review on cutting tool technology in machining of Ni-based superalloys is presented to better understand the current status and to identify future directions of research and development of cutting tool technologies. First, past review articles related to the machining of Ni-based superalloys are summarized. Then machinability of superalloys is introduced, together with the reported methods used in cutting tool design. The current researches on cutting tools in the machining of superalloys are presented in different categories in terms of tool materials, i.e. carbide, ceramics, and Polycrystalline Cubic Boron Nitride (PCBN). Moreover, a set of research issues are identified and highlighted to improve the machining of superalloys. Finally, discussions on the future development are presented, in the areas of new materials/geometries, functional surfaces on the cutting tool, and data driven comprehensive optimization.
... However, under these conditions, the wear was higher and more expressive, with the beginning of the development of a BUE under the conditions tested at a L cut = 15 m. The beginning of the development of a BUE indicates a large amount of adhered material, which tends to generate severe wear [83], as this mechanism increases abrasive wear and, consequently, leads to the occurrence of the delamination of the coating. Figure 16 illustrates the abrasive wear and material adhesion, both on the coating and the tool substrate, and Figure 17 illustrates the beginning of BUE development. ...
... However, under these conditions, the wear was higher and more expressive, with the beginning of the development of a BUE under the conditions tested at a Lcut = 15 m. The beginning of the development of a BUE indicates a large amount of adhered material, which tends to generate severe wear [83], as this mechanism increases abrasive wear and, consequently, leads to the occurrence of the delamination of the coating. Figure 16 illustrates the abrasive wear and material adhesion, both on the coating and the tool substrate, and Figure 17 illustrates the beginning of BUE development. ...
Inconel 718 is a Ni superalloy with superior mechanical properties, even at high temperatures. However, due to its high hardness and low thermal conductivity, it is considered a difficult-to-machine material. This material is widely used in applications that require good dimensional stability, making the milling process the most used in machining this alloy. The wear resulting from this process and the quality of the machined surface are still challenging factors when it comes to Inconel 718. TiAlN-based coating has been used on cutting tools with Yttrium as a doping element to improve the process performance. Based on this, this work evaluated the machined surface integrity and wear resistance of cutting tools coated using Physical Vapor Deposition (PVD) HiPIMS with TiAlYN in the end milling of Inconel 718, varying the process parameters such as cutting speed (vc), feed per tooth (fz), and cutting length (Lcut). It was verified that the Lcut is the parameter that exerts the most significant influence since, even at small distances, Inconel 718 already generates high tool wear (TW). Furthermore, the main wear mechanisms were abrasive and adhesive wear, with the development of a built-up edge (BUE) under a125 m/min feed rate (f) and a Lcut = 15 m. Chipping, cracking, and delamination of the coating were also observed, indicating a lack of adhesion between the coating and the substrate, suggesting the need for a good interlayer or the adjustment of the PVD parameters.
... In addition, there is an increasing demand of customization, being at the same time in a global competition with competitors all over the world. This trend, which is inducing the development from macro to micro markets, results in diminished lot sizes due to augmenting product varieties (high-volume to low-volume production) [1]. To cope with this augmenting variety as well as to be able to identify possible optimization potentials in the existing production system, it is important to have a precise knowledge of the product range and characteristics manufactured and/or assembled in this system. ...
... The low thermal conductivity of the alloys contributes to a very high temperature in the cutting zone. Narutaki et al. [1] and Kitagawa et al. [2] have experimentally shown that in turning of Inconel 718 under conventional cooling, temperature on the rake face of ceramic tools reaches 900°C at the cutting speed of just 30 m/min and climbs to 1300°C at 300 m/min. At high temperature the tool materials soften, thus they can be easier eroded by abrasion. ...
Machining of heat resistant aerospace materials such as Inconel 625 or Inconel 718 is characterized by low cutting speeds, high tool wear rate, and high production costs. The machinability of heat resistant super alloys is low due to high hardness and low thermal conductivity of the nickel-based alloys. The paper presents a study on turning of Inconel 625 with ceramic cutting tools with different methods for application of cutting fluid. It is shown that high-pressure cooling gives excellent chip breaking. The tool life of ceramic cutting tools is not improved by increased coolant pressure.
... Analysis of temperature in cutting zone when machining of Inconel 718 has been addressed by some studies in past, especially in turning technology, where was occurred some deviations of temperatures in cutting zone measured by researchers, dependent on cutting conditions and temperature is higher about 50°C than in used measuring method. Narutaki and his colleagues [3] performed the high-speed experiments when turning up to cutting speed 500m.min -1 (applied process liquid) with ceramic cutting tool. ...
... The various temperatures of various position in the cutting zone correspondent with distribution of heat sources. It is well known that temperature rises with rising deformation of machined material and reach the maximum in the point where the machined material leaves the zone of the primary plastic deformation [3]. Temperatures of workpiece-tool and chip-tool contacts can increase because of friction. ...
Quality of machined surface is affected by quality of cutting process. There are many parameters, which influence on the quality of the cutting process. The cutting temperature is one of most important parameters that influence the tool life and the quality of machined surfaces. Its identification and determination is key objective in specialized machining processes such as dry machining of hard-to-machine materials. It is well known that maximum temperature is obtained in the tool rake face at the vicinity of the cutting edge. A moderate level of cutting edge temperature and a low thermal shock reduce the tool wear phenomena, and a low temperature gradient in the machined sublayer reduces the risk of high tensile residual stresses. The thermocouple method was used to measure the temperature directly in the cutting zone. An original thermocouple was specially developed for measuring of temperature in the cutting zone, surface and subsurface layers of machined surface. This paper deals with identification of temperature and temperature gradient during dry peripheral milling of Inconel 718. The measurements were used to identification the temperature gradients and to reconstruct the thermal distribution in cutting zone with various cutting conditions.
... Furthermore, it was seen that INCONEL ® 718 commonly adheres to cutting tools [85]. Therefore, due to material adhesion, the tendency is to generate severe wear [86] and, consequently, higher abrasive wear, which leads to coating delamination [87]. The sequence observed for these wear mechanisms led to the understanding that, initially, the main wear mechanism is abrasion, because the coating is hard enough to make contact with the workpiece material and sustain its hardness effect. ...
The use of coatings on cutting tools offers several advantages from the point of view of wear resistance. A recent technique with great coating deposition potential is PVD HiPIMS. TiAlN-based coatings have good resistance to oxidation due to the oxide layer that is formed on their surface. However, by adding doping elements such as Vanadium, it is expected that the wear resistance will be improved, as well as its adhesion to the substrate surface. INCONEL® 718 is a nickel superalloy with superior mechanical properties, which makes it a difficult-to-machine material. Milling, due to its flexibility, is the most suitable technique for machining this alloy. Based on this, in this work, the influence of milling parameters, such as cutting speed (Vc), feed per tooth (fz), and cutting length (Lcut), on the surface integrity and wear resistance of TiAlVN-coated tools in the milling of INCONEL® 718 was evaluated. The cutting length has a great influence on the process, with the main wear mechanisms being material adhesion, abrasion, and coating delamination. Furthermore, it was noted that delamination occurred due to low adhesion of the film to the substrate, as well as low resistance to crack propagation. It was also observed that using a higher cutting speed resulted in increased wear. Moreover, in general, by increasing the milling parameters, machined surface roughness also increased.
... Conversely, a more pronounced increase is observed from L cut = 53.6 m to L cut = 73.7 m. Consequently, as is commonly concluded, the greater the TW, the lower the quality of the machined surface [59]. Regarding f, there is a general trend where an increase leads to a surplus in VB. ...
A consistent evolution in materials developed for the industry and chip-start cutting processes has been acknowledged over the years. Cutting tool improvement through applying advanced coatings has proven very effective, enabling tool life (TL) extension while ensuring better surface quality. TiAlTaN coating enhances TL and surface quality in machining processes. However, only minimal research has been dedicated to comprehending the interaction between workpieces composed of Cu-Be and diamond tools. AMPCO®, a Cu-Be alloy, plays a crucial role in moulding inserts, offering high wear resistance and contributing to extended mould longevity and improved productivity. The main objective of this work is to assess, identify, and quantify tool wear (TW) mechanisms evaluation while machining AMPCO® with WC-Co uncoated tools and TiAlTaN-coated tools by physical vapour deposition (PVD). Evaluating tool performance while varying cutting length (Lcut) and feed rate (f) at three distinct levels and analysing the surface roughness (SR) produced in the machined surface were the primary purposes of this work. The results obtained with coated tools were distinct from those obtained with uncoated tools. While uncoated tools suffered from substrate abrasion and adhesion, the coated tools suffered mainly from delamination, followed by chipping. Furthermore, f and Lcut significantly influence the quality of the machined surface. TiAlTaN-coated tools performed significantly worse than uncoated tools, proving that the coating needs significant improvements to be considered as an alternative in milling Cu-Be alloys.
... It has been determined that processing alterations, which influence the Stellite alloy's microstructure, are likely to impede the performance of corrosion [3]. The strengthening of Co-based alloys is generally enhanced by using elements such as tungsten, molybdenum, chromium, and columbium [4,5]. A number of varieties of these alloys are commercially available, which are widely employed nowadays in applications requiring exceptional wear resistance, corrosion resistance, and heat resistance at high temperatures [6]. ...
The objective of the study was to check the feasibility of machining Stellite 6, a cobalt–chromium superalloy, using TiN-coated carbide inserts in an end milling operation. The inserts were coated using the magnetron sputtering process. The sputtering power and gas flow rate were considered as the variables during the coating process. The performance of the coated binary carbide insert was checked during the end milling of Stellite 6 (~45 HRC) through an experiment with a Taguchi design. Experimental runs based on an orthogonal array were executed for each insert type to check the feasibility of machining this cobalt-based alloy. Adequate precision and the optimum parametric conditions were determined and are reported in this study. Analysis of variance (ANOVA) with a two-factor interaction model was also undertaken to forecast the key elements influencing surface roughness. Based on the ANOVA model, the depth of the cut, combined with the insert type, was the factor that had the greatest influence on surface roughness, followed by the cutting feed, whereas the cutting velocity had the least significance based on the tests. Moreover, the regression analysis demonstrated that the created model can be used to accurately forecast surface roughness in end milling of Stellite 6 with confidence intervals of 95%.
... The notch formation and wear mechanisms of ceramic cutting tools were investigated by various researchers. Narutaki [10] reported that SiC whisker-reinforced alumina showed good performance with respect to notch wear in the cutting speed range of 100-300 m/min. The notch wear was considered to be caused by adhesion of workpiece material to the tool, while the flank wear was generated by the diffusion between workpiece material and ceramic tool elements. ...
Nickel-based alloys, referred to as the most difficult-to-cut materials, pose a great challenge to cutting tool materials due to their excellent high-temperature properties. Ceramic tools have the potential to improve the machinability of these alloys with the advance of toughening mechanisms. In this work, the wear mechanisms of SiC whisker-reinforced alumina and Sialon when high-speed turning Inconel 718 alloy under dry cutting condition were investigated. The results showed that the wear process of Al2O3-SiCw WG300 was dominated by the notch wear, while the flank wear characterized by ridges and grooves perpendicular to the cutting edge was the main wear mode for Sialon SX9. A Ti−enriched belt was found at the boundary of the wear band for both ceramic tools. The SEM inspection and EDS analysis for this belt suggested the trace of diffusion between the workpiece material and tool matrix. As for the notch formation, the periodically adhesive action of the workpiece material at the depth-of-cut line combined with the thermal shock resistance of ceramic tools were considered to account for its formation. In addition, the oxidation of the workpiece material at the depth-of-cut line played a positive role in reducing the adhesive affinity and consequent notch wear.
... There was observed some differences of temperatures in the cutting zone measured by different researchers. They were caused by different cutting conditions [18]. In turning experiments, with a high cutting speed (up to 510 m/min), when a process liquid was applied, and when the ceramic cutting tool was used, the measured temperature was in the range between 900 • C and 1300 • C on the rake face of the cutting tool. ...
The paper deals with the issue of cutting zone and chip compression. The aim was to analyse the microstructure transverse section of the cutting zone on a metallographic cut, due to determined values of chip compression and plastic deformation, which affect the cutting process efficiency. The tested cutting tool material was coated with cemented carbide. The selected workpiece materials were C45 medium carbon steel of ISO grade and 62SiMnCr4 tool steel of ISO (W.Nr. 1.2101) grade. In the experiments, a DMG CTX alpha 500 turning centre was used. The cutting speed and feed were varied, and the depth of the cut was kept constant during the turning. The plastic deformation and chip compression determine the efficiency of the cutting process. The higher compression requires more work to perform the process and, therefore, it requires more energy for doing so. With the increase of the cutting speed, the deformation for C45 steel is decreased. The rapid deformation reduction was observed when the cutting speed was increased from 145 m/min to 180 m/min. Generally, deformation is decreasing with the increase of the feed. Only at a cutting speed of 145 m/min was the deformation elevation observed, when the feed was increased from 0.4 mm to 0.6 mm. During the turning of the 62SiMnCr4 tool steel we observed an error value at a cutting speed of 145 m/min and a feed of 0.4 mm was the middle cutting parameter. However, feed dependence was clear: With an increase of the feed, the plastic deformation was decreasing. This decreasing was more rapid with the increasing of the cutting speed. Besides plastic deformation, there was analysed chip compression as well. With the increasing of the cutting speed, there was a decrease of the chip compression. Due to a lack of information in the area of the chip compression and the plastic deformation in the cutting process, we decided to investigate the cutting zone for the turning of tool steels 62SiMnCr4, which was compared with the reference steel C45. The results could be applied to increase the efficiency of the process and improvement of the surface integrity.
... As a result, thermocouples have been used extensively for non-dry machining conditions. In this case, thermocouples are embedded inside the cutting tool with the bulb close to the cutting edge and fastened with highly conductive thermopastes, as explained by Narutaki et al. (1993). Jafarian et al. (2014) also demonstrated that the machining temperature on the cutting edge can then be estimated with reverse numerical models. ...
Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.
This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.
... Previously, the applicability of IN-718 has somewhat been limited by its high hardness, low thermal conductivity, work hardening properties, and high cutting forces causing difficulties in its machinability. This results in high cutting tool temperatures 10 and even leads to metallurgical changes which ultimately damage the workpiece 11 . ...
Ni-based super alloy Inconel-718 is ubiquitous in metal 3D printing where a high cooling rate and thermal gradient are present. These manufacturing conditions are conducive to high initial dislocation density and porosity or void in the material. This work proposes a molecular dynamics (MD) analysis method that can examine the role of dislocations, cooling rates, void, and their interactions governing the material properties and failure mechanisms in Inconel-718 using Embedded Atom Method (EAM) potential. Throughout this work, three different structures-nanowire (NW), nanopillar (NP), and thin-plate are used. Strain rate is varied from 10 8 s⁻¹ to 10 10 s⁻¹ and temperature is varied from 100 K to 800 K. Different cooling rates ranging from 0.5 × 10 10 K/s to 1 × 10 14 K/s are applied. Our results suggest that the high cooling rates create regular crystalline structures which result in high strength and ductility. In contrast, the lower cooling rates form a non-crystalline structure that exhibits low strength and brittle nature. This brittle to ductile transition is observed solely due to cooling rate at nanoscale. Elimination of voids as a result of heat treatment is reported as well. Shockley dislocation is observed as the key factor during tensile plastic deformation. Increasing strain rates result in strain hardening and higher dislocation density in tension. Our computational method is successful in capturing extensive sliding on the {111} shear plane due to dislocation, which leads to necking before fracture. Furthermore, notable mechanical properties are revealed by varying temperature, size and strain rate. Our results detail a pathway to design machine parts with Inconel-718 alloy efficiently in bottom-up approach.
... The temperature measured [16] at the tool-chip interface increases with Vc, at 30 and 90 m/min, respectively, and was 910 and 1130 • C and [17] observed the same trend and range. The chip temperature measured by the infrared camera [6,7] in turning the IN718 alloy with MQL and Vc = 60 m/min was 575 • C, and under dry cut the chip temperature increased to 846 • C. A fiber-optic two-color pyrometer [15] was used for the localized workpiece temperature measurement in turning the IN718 alloy in the range Vc = 60 to 180 m/min and the workpiece surface temperature increased slightly from 420 to 450 • C with f = 0.05 mm/rev at higher Vc, but decreased slightly from 295 to 255 • C at higher Vc with f = 0.1 mm/rev. ...
Products produced by additive manufacturing (AM) seek to exploit net shape manufacturing by eliminating or minimizing post-process stages such as machining. However, many applications which include turbo machinery components with tight dimensional tolerances and a smooth surface finish will require at least a light machine finishing stage. This paper investigates the machinability of the additively fabricated INCONEL718 (IN718) alloy produced by laser melting powder bed fusion (LM-PBF) with different levels of spherical porosity in the microstructure. The literature suggests that the band width for laser energy density, which combines the various scan process parameters to obtain a low spherical type porosity in the LM-PBF IN718 alloy (~1%), has wide breadth. With the increasing laser energy density and above a threshold, there is a rapid increase in the spherical pore size. In this paper, three tube samples each with different levels of spherical porosity were fabricated by varying the laser energy density for LM-PBF of the IN718 alloy within the stable and higher energy density range and the porosity measured. A low laser energy density was avoided due to balling up, which promotes highly irregular lack of fusion defects and poor consolidation within the alloy microstructure. An orthogonal turning test instrumented, with a three-component dynamometer to measure the cutting forces, was performed on AM produced IN718 tube samples under light cut conditions to simulate a finish machining process. The orthogonal turning tests were also performed on a tube sample obtained from the wrought extruded stock. The machining process parameters, which were studied include varying the cutting speed at three levels, at a fixed feed and under dry cut conditions for a short duration to avoid the tool wear. The results obtained were discussed and a notable finding was the higher rate of built-up-edge formation on the tool tip from the AM samples with a higher porosity and especially at a higher cutting speed. The paper also discusses the mechanisms that underpin the findings.
... The presence of Ni and Cr in the bright phase (appearing in Fig. 16a and b) indicates that these metallic elements are more prone to diffuse into the SiC-whiskers/ceramic-matrix boundary rather than into the ceramic matrix itself. Narutaki et al. [29] performed diffusion tests and reported the formation of a Cr-O rich zone near the interface of Al2O3-SiCw and Inconel 718. On the other and, Al2O3-TiC ceramic composite showed much more chemical stability towards Inconel 718 than Al2O3-SiCw. ...
Alumina-based ceramic tools have been successfully applied in high-speed turning of superalloys. In this study, the tribological characteristics of a novel Al2O3-SiCw-TiCn ceramic composite were investigated in unlubricated sliding contact against laser-heated (600 °C) and unheated Inconel 718 between 2.5 m/s and 10 m/s. The tribological behavior of the Al2O3-SiCw-TiCn ceramic was compared to a commercial Al2O3-SiCw ceramic. The results indicated similar coefficients of friction (COF) in laser-heated and unheated tests. Below 7.5 m/s, the wear mechanisms in laser-heated tests were brittle fracture, plastic flow and adhesive wear and predominantly brittle fracture in unheated tests. A tribochemical layer mainly containing chromium and oxygen has formed on the contact surface at 10 m/s resulting in lowering the COF and reducing wear.
... studied the notch wear, chip and burr configuration during machining of Inconel 718 and they found that wear was mostly affected by abrasive process. Similar study was carried out by Narutaki et al. [10]. They concluded that at speed of 300 m/min, the notch wear became large at the depth of cut line, while the average flank wear became very small. ...
Machining is one of the major manufacturing processes that converts a raw work piece of arbitrary size into a finished product of definite shape of predetermined size by suitably controlling the relative motion between the tool and the work. Lately, machining process is shifting towards high speed machining (HSM) from conventional machining to improve and efficiently increase production, and towards dry machining from excessive coolant used wet machining to improve economy of production. And the tools used are mostly hardened alloys to facilitate HSM. The work piece materials are continually improving their properties by emergence and development of newer and high resistive super alloys (HRSA). In this paper an attempt has been made to validate an experimental result of cutting force obtained by performing HSM on an HRSA Inconel 718, by comparing it with the numerical result obtained by simulating the same setting using DEFORM 3D software. Based on the comparison it is found that the simulated results exhibit close proximity with the experimental results validating the experimental results and the effectiveness of the software.
... At the feed rate of 0.32 mm rev_1, notch wear and the average flank wear were large for both of the ceramics. [10] By using ceramic inserts, the cutting speed could be increased from 183 to 381 m/min. Theother machining parameters such as feed rate of 0.20mm/rev and depth of cut of 0.38 mm remained the same. ...
... However, the adhesive wear is a drawback while turning of Inconel 718 alloy [18][19][20]. For lower notch wear, SiC-Al 2 O 3 is better compared with Al 2 O 3 -TiC inserts, but higher flank wear in the cutting speed range of 100-300 m/min [21]. Altin et al. [22] experimented SiC-Al 2 O 3 and sialon tools in the cutting speed range of 150-300 m/min. ...
Liquid nitrogen (LN2) machining is considered as a safe, clean, and environmentally friendly machining process. This paper aims to investigate the vibration, tool wear and surface roughness mechanism of the ceramic insert during turning of Inconel 718 alloy under dry machining and LN2 machining. The experiments were performed at three cutting speeds (100, 150, 200 m/min), feed rates (0.04, 0.08, 0.12 mm/rev) and depths of cut (0.2, 0.4, 0.6 mm). The experiment results show better machinability and longer tool life in LN2 machining. The vibration acceleration is reduced by 14–32%. A 17–34% reduction of workpiece surface roughness is observed. Flank wear and notch are the predominant wear forms both in LN2 machining and dry machining, and 16–34% reduction of flank wear is noted in LN2 machining.
... Research studies [1][2][3][4][5][6] have clearly established that the machining of heat resistive alloys like Inconel has continuously faced the challenges in the present millennium. High material strength, creep and corrosion resistance have made nickel-based alloys attractive materials for aerospace, gas turbine and nuclear industries. ...
Inconel-800 is a superalloy having moderate strength, sufficient resistance to oxidation at high temperature and carburization. Work hardening nature of the material makes it very hard to machine using traditional methods. Wire-cut electrical discharge machining (WEDM) is most widely applied for difficult-to-machine materials because of its capability to produce jobs with minute accuracy and precision. Time taken to process job is the major drawback of the WEDM technique. Therefore, the need arose for formulating a stable predictive model which reduces human effort and maximizes production. The comprehensive intention of this study is to develop robust and stable multi-objective decision-making and soft computing models for selecting the best machining parameters and forecasting the machining performance of Inconel-800 superalloy. Taguchi’s method is applied for designing the experimental phase of the study. The computational part is a three-stage process. The first stage is selecting the best machining parameters of WEDM by multi-criteria decision-making (MCDM) technique. A novel MCDM technique is proposed that is based on the concept of risk minimization. The second stage involves the formulation of predictive model using soft computing technique like response surface methodology (RSM). The performance of the technique was scrutinized on a statistical platform to check the gullibility of the model. The final stage is the trade-off analysis by multi-objective RSM (MORSM) which strategically draws balance among the multiple outputs of the problem. Finally, the proposed MCDM and MORSM models are applied for selecting the best and optimal combination of machining Inconel-800 by WEDM technique.
... In high-speed machining of Inconel 718, the wear of ceramic tools can be accelerated due to diffusional wear (due to the diffusion of silicon) caused by high cutting temperature [13]. Bhattacharyya et al. found that a diffusion zone formed between the SiAlON ceramic tool and Inconel 901 above a speed of 185 m/min [14]. ...
Silicon nitride based ceramic tools have been successfully applied in high speed machining of nickel-based alloys. In this study, three silicon nitride material systems with different intergranular glassy phase contents were used to study the tribological behavior of silicon nitride in dry sliding against Inconel 718 in order to evaluate their potential suitability as cutting tool materials. The tribological properties at sliding velocities ranging from 1 m/s to 20 m/s were investigated. The mechanical and microstructural properties of ceramics were considered, and the wear mechanisms were analyzed. The results showed that the wear of the ceramics has a positive correlation with hardness for sliding velocities below 5 m/s. With increasing sliding velocity, a tribochemical layer consisting of an oxide layer and a diffusion layer forms at the interface, resulting in increasingly higher wear of the ceramic. The formation of a tribochemical layer showed a correlation with the amount of the intergranular glassy phase in the material; the higher its amount the more prone the silicon nitride ceramic was found to form a tribochemical layer.
... The most significant properties exhibited by Inconel 718 are the capability of maintaining high stiffness and strength at high temperature, high dynamic shear strength and extremely low reactivity in highly corrosive environment. Although the Inconel 718 has these beneficial properties in hostile working conditions, it shows poor workability due to its high work hardening, low thermal diffusivity and high reactivity with tool materials [2]. ...
Inconel 718 nickel-based super alloy is widely used in aerospace, nuclear and marine industries due to its important thermo-mechanical properties and excellent corrosion resistance. However, the possibility to produce parts with a superior surface quality (e.g. enhanced surface integrity) still represents a challenge for manufacturing industry since the standard processing parameters are not suitable when difficult-to-cut materials are involved. Thus, predictive models represent a useful tool to simulate the material behavior during machining. Physics based computational analysis is an excellent technique to analyze the micro-scale phenomena (e.g. dynamic recrystallization, density of dislocation changes) taking place during the plastic deformation processes. Thus, it represents an important tool to optimize the cutting process achieving the desired characteristics of the machined surface. This work presents a physics based model developed to assess the micro-mechanical behavior of Inconel 718 super alloy subject to severe machining operations. Results show the good capability of the model to properly deal with the main physical phenomena taking place during the process and to correctly predict the main surface modifications which affect the final product performance.
... Narutaki et al. [6] were observing tool wear of three different ceramic tools when turning Inconel 718. They realized, if they use lower cutting speeds (100-300 m/min), best durability offers ceramic Al 2 O 3 with added silicon carbide. ...
Machining of nickel based alloys is in most of the times affected via high mechanical and thermal loads, causing high wear tendency of carbide tools, even at relatively low cutting speeds. On the other hand, ceramic as a cutting material, is more chemically stable and retains its hardness even at higher temperatures (> 800 °C) when machining difficult‐to‐cut materials. Therefore, to increase productivity, as an alternative to carbide tools, full body ceramic milling tools are proposed. In this paper, high speed milling process, using full body ceramic end milling tools, was analysed in parallel to carbide tools. Tool life of ceramic tools was compared with tool life of more widely used carbide tools when milling two different difficult‐to‐cut materials, i. e. nickel based alloy Inconel 718 and austenitic stainless steel 316L, under different cooling lubrication conditions. In addition, surface integrity and cost analysis were taken into account. Results are showing that ceramic milling tools are increasing material removal rate and productivity. However, the overall efficiency of ceramic tools can still be economically questionable.
... Exceptionally high tensile strength, fracture toughness, and wear resistance at relatively high temperature make this alloy an attractive material for application in high heat, wear, and corrosive environments such as turbine, nuclear reactors, jet engines, and combustion chambers. At the same time, these properties make it extremely difficult to machine [35][36][37]. Therefore, L-PBF is an attractive method to manufacture high-density Inconel 718 components. ...
The melt pool characteristics in terms of size and shape and the porosity development in laser powder bed fusion–processed Inconel 718 were investigated to determine how laser power and scan speed influence the porosity in the microstructure. The melt pool characteristics developed with both single-track and multilayer bulk laser deposition were evaluated. It was found that the melt pool characteristic is critical for the porosity development. It is shown that the porosity fraction and pore shape change depending on the melt pool size and shape. This result is explained based on the local energy density of a laser during the process. High-density (> 99%) Inconel 718 samples were achieved over a wide range of laser energy densities (J/mm2). A careful assessment shows that the laser power and scan speed affect differently in developing the pores in the samples. The porosity decreased rapidly with the increase in laser power while it varied linearly with the scan speed. A proper combination, however, led to fully dense samples. The study reveals an optimum condition in terms of laser power and scan speed that can be adopted to fabricate high-density Inconel 718 parts using laser powder bed fusion–based additive manufacturing process.
... Alumina (Al 2 O 3 ) ceramic tools retain adequate hardness at high cutting temperatures, and they are chemically stable with respect to Ni. 7 The fracture toughness of Al 2 O 3 ceramics can be improved by adding ZrO 2 and its thermal shock resistance with the addition of TiC and TiN. 32,33 Fibers or whiskers of silicon carbide (SiC) are added to improve the toughness of Al 2 O 3 ceramic tools and increase the thermal conductivity, since SiC has a very high tensile strength. This tool is mainly used to machine nickel-based superalloys with reasonable tool life. ...
Direct aged Inconel 718 superalloy is used in manufacturing critical cross-sections of aero-engine components. It is a hard-to-machine material, especially in dry conditions. To perform successful machining operations for this alloy, cutting tools with high hot hardness and chemical stability are required. The present study investigates the tool wear and chip formation during dry finish turning of direct aged Inconel 718 superalloy (51–53 HRC) using different ceramic tools. Pure alumina with added ZrO2 and alumina matrix reinforced with silicon carbide whiskers tools were used at cutting speeds of 150 and 250 m/min. A scanning electron microscope and energy dispersing spectroscopy were utilized to study the tool wear mechanisms. Structural and phase transformations during cutting on the tool–chip interface at the higher cutting speed were analyzed with X-ray photoelectron spectroscopy. Chip-undersides and cross-sections were studied with scanning electron microscope to investigate the chip formation mechanism. Results reveal that pure alumina with added ZrO2 can be an adequate choice for machining direct aged Inconel 718 because of its higher abrasive wear resistance and the formation of a sapphire protective tribo-layer at the tool–chip interface under severe cutting conditions. Chipping and notching of the cutting edge was found to decrease with the rise of the cutting speed for this tool material. As confirmed by X-ray photoelectron spectroscopy, alumina reinforced with silicon carbide whiskers tool was found to have a lower performance due the chemical degradation of the whiskers, especially at the higher cutting speed (250 m/min).
... Concentrated temperature together with rapid strain hardening of NiTi are mainly responsible for this kind of wear. Notch wear may be minimized by using a tougher tool material, chamfering tool edge [107], altering cutting parameters [42], or using varying depth of cut strategy [108] if multiple passes are made. In the turning of NiTi with carbide tools, increasing cutting speed to V c = 100 m/min resulted in reduced notch wear owing to reduced cutting forces [42,82]. ...
Nickel–titanium (NiTi) shape memory alloys have gained more prominence due to their functional and mechanical properties. This material undergoes solid-state phase transformation during machining. Together with this, inherent properties of this material result in challenging machinability behaviors such as excessive tool wear, high cutting forces, and degraded surface integrity. Furthermore, unique stress–strain curve of this material complicates predicting machining behaviors. This paper reviews research in the machining of NiTi shape memory alloys carried out over the last 20 years with the objective of assessing overall machinability characteristics. It is concluded that functional properties and machinability responses of NiTi are very sensitive to machining parameters and environment. Machinability rate of NiTi should be assessed not only by usual machinability measures (i.e., tool wear, cutting forces, surface integrity) but also by considering post machining functional behaviors.
... Several attempts, including different tool geometries and materials [6], coatings [7][8][9][10] and machining strategies [11][12][13] have been employed for improving the chipping resistance and overall tool life of the tools during machining of Inconel. However, the challenge has not been resolved yet resulting in low cycle times, high tooling costs and the production of excessive scrap. ...
Chipping and high tool wear are considered the most challenging issues associated with machining of superalloys, including Inconel 718. Despite numerous attempts in this area, it is still considered a critical drawback of this class of materials for application in different industries. A new tool treatment technique is proposed for improving the tool wear and reducing the chipping during machining of Inconel 718. The treatment involves less than two seconds of machining on an aluminum-silicon (Al-Si) workpiece prior to the actual machining of Inconel. In this way, the “pre-machining process” deposited a very thin layer of Al-Si on the tool face. During the subsequent machining of the Inconel bar, the Al-Si was melted due to the high temperatures of Inconel machining. The molten material channeled itself through the microcracks on the tool surface and seized their propagation. The sliding of the tool on the low friction Al-Si layer resulted in much lower forces, less sticking, seizure and built-up edge formation and, thereby, in less tool wear and chipping. Several beneficial lubricious and thermal barrier tribo-films were also formed on the tool face, which further protected the tool from chipping and severe tool wear. Reducing the contact pressure, friction and temperature during machining resulted in considerable reduction in the machining induced work-hardening of the workpiece material, which is considered as one of the most important factors affecting chipping during machining of this class of materials. Moreover, the ductility of Al helped to dampen the vibrations during machining and helped in tool chipping prevention. Finally, the preconditioning of the tool itself through this process resulted in tool performance improvement by lowering the tool wear at the running-in stage. The new method resulted in a significant reduction in tool chipping and an overall improvement in tool life. Considerable improvements in the surface integrity of the machined part were also obtained. The contributing mechanisms are discussed using detailed material characterization techniques.
... These materials are difficult for machining and show low machinability. These materials are widely researched by researchers concentrating mainly on cutting force, surface roughness, tool wear mechanism and tool life in different common machining processes (i.e., turning, milling and drilling) [2,3]. Li et al. [4] conducted machining experiments on Inconel 718 using coated carbide and ceramic inserts and optimized process parameters for obtaining maximum tool life. ...
Sustainability is a vital issue for present and future generation, and it aims to obtain overall efficiency in terms of economic, environmental and social aspects. Inconel 825 belongs to the family of nickel-based super alloy and is widely used in the chemical and marine industries. This work attempts to investigate machining performance of Inconel 825 using physical vapor deposition-titanium nitrate inserts, with a focus on sustainable machining. The effect of cutting parameters, viz. cutting speed (v), feed (f) and depth of cut (d) on three aspects of sustainability has been explored in two different machining environments, viz. dry and minimum quantity lubrication (MQL). The experimental results show a significant improvement in MQL machining and tool wear, and cutting power is reduced by 16.57 and 8.47%, respectively, and surface roughness is improved by 10.41%. The interacting effects of parameters on responses are studied using 3-D surface plots; it shows cutting speed and feed are found as dominating parameters on all the three responses. The novelty of this work is to optimize the process for the sustainable production of components by optimizing the process parameters with multiple and conflicting objectives. The sustainable optimization using genetic algorithm provides surface roughness (Ra) as 0.49 µm, tool flank wear (VB) as 110.68 µm and cutting power (P) as 5.44 kW with better convergent capability having 4% deviation. For the application of manufacturing industry, an optimization table is generated for selection of optimum process parameters for achieving desired surface roughness with minimum VB or minimum P. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.
... The performance of pure oxide ceramic tools is improved by adding titanium carbide (TiC) [6]. Silicon carbide (SiC) whiskerreinforced alumina tools gave lower notch wear than Al 2 O 3 -TiC tools, but higher flank wear, in the cutting speed range of 100-300 m/min [7]. Altin et al. [8], on the other hand, conducted comparison experiments between SiC whiskerreinforced alumina tools and sialon tools in the cutting speed range of 150-300 m/min and found that the dependences of flank wear on the cutting speed were similar between the two ceramic tools, and the optimum cutting speed was around 250 m/min for both the ceramic tools. ...
High-speed turning of Inconel 718 was challenged by using TiAlN-coated tungsten carbide tools of positive and negative types, and aluminum-rich (Al, Ti) N-coated ones of negative type. It is found that the (Al, Ti) N negative inserts have much longer tool life than the TiAlN inserts of both the positive and negative types at all the cutting speeds tested. The skirt flank wear was almost the same in mechanism, which was dominated by adhesive wear and abrasive wear for the three types of inserts at the all cutting speeds tested. The cutting edge flank wear changed greatly both in magnitude and in mechanism depending on the type of the insert and the cutting speed. The rake wear was almost limited within the cutting area and at tool life the coatings in the cutting area were all worn off except of the (Al, Ti) N negative inserts tested at the cutting speed of 200 m/min. The hardness of the turned surfaces was always higher than that as received, and the increase in the hardness was greatest for the (Al, Ti) N negative inserts among the three types of the inserts.
Nickel-based superalloys have gained widespread use in various industries like aerospace, power generation, chemical processing, and marine engineering due to their exceptional mechanical properties. However, machining these superalloys poses significant challenges due to their hardness. To address these issues and improve machining performance, selecting suitable cutting tool materials and coatings is crucial. This state-of-the-art review aims to provide an in-depth understanding of the latest research on cutting tool materials and coatings in enhancing the tool performance in machining the superior nickel-based superalloys. It begins by examining the applications and current challenges associated with machining these alloys. Different types of cutting tool materials, including cemented carbides, ceramic-based tools, and super-hard materials like polycrystalline cubic boron nitride, are analyzed, with a particular focus on tool geometry and failure. The advantages, limitations, and specific applications of each tool material are highlighted. Additionally, the role of coatings in enhancing cutting tool performance is explored. Various coating types, including titanium nitride (TiN), titanium carbonitride (TiCN), and aluminum oxide (Al2O3), are evaluated based on their effectiveness in machining nickel-based superalloys. The review also covers aspects such as tool wear, cutting forces, the surface roughness of machined parts, heat generation, and temperature measurement techniques employed by researchers to assess cutting tool performance. It underscores the importance of tailoring the selection of cutting tool materials and coatings to specific machining conditions for optimal results. The review concludes by summarizing key findings and suggesting potential areas for future research.
Cutting tool materials often undergo severe mechanical stresses and thermal changes when machining nickel-based superalloys. The stresses and temperatures that arise when machining nickel-based superalloys greatly increase the blunting and wear rate of the cutting tool. As a result, tool life is adversely affected. It is seen from important studies that adhesion and abrasion wear mechanisms are more dominant in the processing of Inconel 718. The work material adheres to the cutting edge, forming a BUE. Depending on the cutting conditions, stable BUE is not always formed and this layer is sometimes repeatedly removed with the chips. Notching in the depth of cut, wear on the tool nose and coating layer is caused by the presence of hard particles in Inconel 718 and causes severe flank wear. Flank wear and notch are the main factors limiting tool life, and oxidation and diffusion occur as a result of high temperatures.
Additive technologies make it possible to provide high quality products (accuracy and uniqueness of geometry, high complex of mechanical properties, high density (low porosity), uniformity of microstructure and chemical composition). A wide range of materials used allows it to find application in such industries as medical and dental, engineering, automotive and aerospace. At present, technological capabilities, the development of laser technologies and CAD modeling systems have made it possible to develop devices for building parts by loading the original CAD model and fusing metal powder using a laser in accordance with it – what is today called SLM technology. During this process, the metal powder is completely melted under the influence of high-power laser radiation with the formation of a metal layer that contains almost no pores and does not require further processing, which makes it possible to achieve a level of mechanical properties of the product equal to or even better than those of cast ones. To create advanced equipment and professional control of the process of manufacturing parts, a deep understanding of the processes occurring in the melt pool under the laser beam and after hardening is necessary. At the same time, the final quality of products manufactured using SLM technology depends on many factors that can be divided into main groups: equipment (calibration, laser power, energy distribution in the beam, powder application system, shielding gas supply, distribution and purification system, system ensuring the tightness of the chamber, etc.), material (sphericity, dispersion, bulk density, fluidity, properties, handling, etc. of metal powder), process parameters, geometry features of the part, finishing. Prospects for the development of technology in Ukraine are associated with the development of new structural materials, solving topology optimization problems, prototyping, studying the properties of materials and creating the latest production solutions in the field of additive technologies.
High speed machining is an inevitable challenge in milling of hard-to-machine materials. These materials have poor thermal conductivity which precludes efficient heat dissipation, resulting in extremely high temperatures in the cutting zone. These high temperatures cause reduction of tool life and deterioration of surface finish. As a result, machining Inconel is often associated with low productivity and high machining costs. In this paper, the impact of various cooling techniques on machinability of Inconel alloy in high speed milling is investigated. The investigations clearly revealed that machining Inconel 718 at high speeds with a novel combination cooling system consisting of chilled air cooling and minimum quantity lubrication offers significant advantages. The analysis indicated that tool life was extended by threefold using chilled MQL when compared to dry and chilled air whilst generating an average surface roughness Ra of 0.28 µm.
This book presents the selected peer-reviewed proceedings of the International Conference on Thermal Engineering and Management Advances (ICTEMA 2020). The contents discuss latest research in the areas of thermal engineering, manufacturing engineering, and production management. Some of the topics covered include multiphase fluid flow, turbulent flows, reactive flows, atmospheric flows, combustion and propulsion, computational methods for thermo-fluid arena, micro and nanofluidics, renewable energy and environment sustainability, non-conventional energy resources, energy principles and management, machine dynamics and manufacturing, casting and forming, green manufacturing, production planning and management, quality control and management, and traditional and non-traditional manufacturing. The contents of this book will be useful for students, researchers as well as professionals working in the area of mechanical engineering and allied fields.
In the last four decades, industries have gone through several gigantic changes; and a very significant progress is also witnessed in the field of alumina and associated cutting tool industry. This paper presents a review on the development of alumina-based ceramic cutting tools. Alumina based materials are used as cutting tools due to its favorable mechanical properties like high abrasive wear resistance, less tendency of weld to metal, high compressive strength, hot hardness, high refractoriness, high cutting speed and longer tool life. To obtain performance and efficiency wise better cutting tool; it must have good strength even at high temperatures, its coefficient of thermal expansion should be low, resistance to oxidation and thermal conductivity must be high. Alumina based cutting tool proved efficient in correspondence to the above-mentioned characteristics. This study will help the future researchers of this field to obtain a concise views and ideas in development of mixed alumina oriented cutting tools from its very beginning to the present day.
The characteristics of single-track melt pools, such as size, shape, and stability, formed by the heatresistant Inconel 718 nickel alloy powder subjected to selective laser melting (SLM) were studied. The objective was to determine the range of optimal SLM parameters to provide a stable track with a depth of two to three layers. Single tracks were built using various combinations of process parameters: laser power from 50 to 400 W with a step of 30 W and scanning speed from 450 to 1000 mm/sec with a step of 50 mm/sec (144 modes in total). An Axiovert 200M MAT light microscope (Carl Zeiss) was employed to examine the cross sections of single tracks and evaluate the geometrical parameters of the melt pools. Features pertaining to the effect of the scanning speed and laser power on single-track depth and width and their ratio were experimentally studied. An unstable track formed at low power (P = 50 W) and low scanning speed (V = 450–500 mm/sec), while no track appeared at all at higher speeds. A stable track formed at power P = 80–200 W at low speeds (V = 500–900 mm/sec) and became unstable and intermittent when speed increased to V = 1000 mm/sec. With higher laser power (P = 230–400 W) and low process speeds, a continuous track formed but had an increased variable width, being indicative of a deviation from the stable track formation conditions. It was first established that the intensity of the scanning speed effect (450–1000 mm/sec) on the single track depth varies by more than 2.5 times depending on the laser power (50–400 W). The process parameters that would ensure the formation of an optimal single track in terms of geometric parameters were determined.
Uncoated WC-Co tool insert was volumetrically heated through microwave irradiation to explore potential benefits of mechanical properties including higher hardness, lower residual stress, and better wear resistance, which in turn improves machinability of “difficult-to-cut” Inconel 718 superalloy. A household domestic microwave oven was used for microwave irradiation, in which activated charcoal powder was used as a microwave susceptor. Dry turning experiments were conducted on Inconel 718 work piece using microwave-treated tool at varied cutting speeds; corresponding tool-tip temperature and flank wear depth were measured. It was found that, compared with conventional (untreated) insert, better machining performance is attributed to a microwave-treated insert. Detailed analysis on tool wear morphology was also carried out.
Machining of the nickel-based alloy is very demanding due to its extreme mechanical properties, for example, higher fatigue strength, better corrosion and creep resistance feature, substantial work hardening capability, and appreciable tensile and shear strength. Owing to these properties , the selection of machining parameters is a major challenge for modern machining industries. Therefore, the present experimental work is carried out to select the best parametric combination of the wire electrical discharge machining (WEDM) machine for reducing machining cost and human effort. The Trapezoidal Interval Type-2 fuzzy number (T2FS) integrated Analytical Hierarchy Process (AHP)-based Additive Ratio Assessment (ARAS) method is used for selecting the best WEDM process parameters of Inconel-800 superalloy. Finally, the results were compared with some existing multi-criteria decision-making methods to confirm the validity of the adopted method. The comparison shows that Type-2 Fuzzy AHP-ARAS synergy can help to formulate the problem and facilitate the assessment and ranking of WEDM process parameters when multiple criteria are jointly considered.
Appropriate selection of tool material is very important for effective machining of ‘difficult-to-cut’ aerospace superalloy Inconel 718, especially, under dry condition. Present work aims at investigating performance of physical vapor deposition (PVD) multi-layer (TiN/TiCN/TiN) coated cermet, and PVD TiAlN coated PCBN (Polycrystalline Cubic Boron Nitride) brazed tipped carbide inserts on machinability of Inconel 718. Machinability is assessed based on cutting force magnitude, maximum tool-tip temperature attained, tool wear morphology, chip macro/micro morphology, and end part surface integrity. Later includes detailed analysis on morphology of the machined surface, roughness, and depth of hardened layer. Results obtained thereof, are compared to that of conventional uncoated WC-Co tool. It is evidenced that coated cermet outperformed other two inserts in purview of lower cutting force, better surface finish, and tiny white layer. WC-Co causes extreme cutting temperature than other counterparts. Up to 86 m/min cutting velocity, PCBN tool exhibits minimal flank wear; afterwards, tool is severely affected by huge notch wear. On the contrary, cermet tool suffers from lower flank wear than WC-Co for all cutting speeds tested. Both cermet and PCBN inserts are found remarkably affected by notching, and coating dissipation. Attrition wear is evidenced only in case of WC-Co insert. Coated cermet, thus, appears as a better choice for dry turning of Inconel 718.
Cryogenic coolants as cutting fluids are gaining significance as they are eco-friendly, recyclable and moreover they do no longer produce any dangerous effect on the operators. Cryogenic liquid nitrogen at −196 °C has commonly used coolant in cryogenic machining industries. This experimental work was performed by milling action of AISI D2 tool steel tool wherein the lubrication effect caused due to cryogenic coolant (LN2) sprayed as a cutting fluid in comparison to the less moist (Dry) and moist (wet) metal removing operations based on tear and wear of tool and roughness of the surface on the machined component. Experiments have accomplished the usage of TiN coated tungsten carbide tool which has different speed combinations and feed rate combinations. The workpiece roughness of the surface was minimized up to 15–28% for dry metal removing as well as 26–38% over moist metal removing. This is because of LN2 machining offers higher lubrication and cooling effect was the minimization in the temperature behind cutting.
Cutting performance and failure mechanisms of graphene nano-platelets (GNPs) reinforced ceramic cutting tool ATG (short for Al2O3/Ti(C,N)/GNPs) in continuous dry turning of Inconel 718 up to a cutting speed of 500 m/min were investigated in comparison with those of commercial Sialon tool KY1540. The results show that ATG tool shows similar cutting performance with KY1540 tool at the speed range of 150–300 m/min, but greatly outperforms KY1540 when the cutting speed range of 400–500 m/min for higher hardness, wear resistance, chemical inertness and fracture toughness. Flank wear, notch wear, chipping and flaking are the reasons for tool failure of ATG. The wear modes are related to cutting speed, and adhesion wear is found to be the dominant failure mechanism of ATG. It is believed that GNPs play a significant role in improving mechanical properties and tribological properties which contributed to excellent resistance to abrasive wear and fracture. Turning Inconel 718 in dry and high speed via using ATG ceramic tool is an efficient and eco-friendly method.
In particle accelerator facilities, single-phase niobium is used in superconducting accelerator components. Machining induced surface quality of such components is strongly connected to the functionality of accelerators. In this study, tool wear development and its influence on the surface quality of Nb workpiece have been investigated in longitudinal turning. Uncoated cemented carbide cutting tools were used under finishing conditions (cutting speed vc = 300 m/min and feed f = 0.05 mm/rev) up to the wear criterion of VBmax = 300 μm. A detailed analysis of wear mechanisms of the cutting tool was conducted with help of high resolution electron microscopy (SEM and TEM). Further, the results obtained were correlated with controlled diffusion couples experiments under high pressure – high temperature conditions (2 GPa and 1000 °C). Diffusion of carbon from WC and formation of NbC was found to occur on the niobium – cemented carbide interface. Electron microscopy of the worn tools reports identical mechanisms of diffusion and chemical interaction which lead to rapid flank wear, yet formation of NbC on the rake completely inhibits tool degradation and thus acts as tool protection layer.
Advanced ceramics exhibit excellent mechanical properties at elevated temperatures suggesting them as plausible cutting tool materials for machining of heat-resistant superalloys. However, despite numerous efforts to date, relative brittleness of ceramic tools can result in chipping or catastrophic failure, especially during an intermittent process where excessive thermo-mechanical alteration occurs, like high-speed face milling. Previous studies by the authors revealed that in high-speed milling of inconel with SiAlON tools, after surpassing a certain cutting speed where extreme levels of strain rates and temperatures exist, the IN718 machinability transforms drastically, showing a significant reduction in cutting force, chipping and tool wear. Following this observation, in the current paper, an attempt has been made to further investigate the phenomena acting at the shear deformation zones through analysis of chip formation mechanisms and tool-workpiece tribosystem. Numerous characterization techniques have been used in this research, such as cutting force measurements, chip cross-section studies, SEM/EDS, TEM, and nanoindentation. Results suggest that a reduction in material flow strength occurs at the extreme conditions of the cut, showing similarities to fluid flow in TEM images of the tool face. Increasing the cutting speed generally facilitates chip formation; However, a rise in cutting force by further increasing the speed, and excessive generation of unstable built-up layers practically limits the cutting speed. Additional XPS studies show that variation in cutting speed also changes the frictional response of the tool-workpiece tribosystem by forming lubricious and thermal-barrier tribofilms.
This work aims to reveal the cutting performance and wear mechanisms of Sialon ceramic tools for the high-speed face-milling of GH4099, with the goal of improving this process as well as designing more advanced ceramic cutting tools in the future. At the outset of this study, several single-factor experiments were designed with speed as a variable to gather various data on such tools. Failure patterns and tool life curves were first obtained through cutting tests. Afterwards, the tools were split at their place of wear (middle of notch and 1/2 depth of cut) to prepare for further analysis. Wear morphology and element composition distribution in the depth direction of the corresponding interface were then analyzed using a field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) to explore potential diffusion and/or chemical wear. Finally, studies were conducted into the tools’ chemical wear under specific cutting conditions, finishing with a theoretical verification based on the thermodynamic principle of chemical reactions. This research discovered that notch wear was the main failure pattern for the high-speed face-milling of GH4099 under the suitable cutting conditions. Overall, the optimal cutting speed was 1000 m/min, with a tool life of about 3 min. Compared with cemented carbide tools, the machining efficiency for Sialon ceramic tools increased by over a factor of 16. The wear mechanisms for such tools demonstrated a mixture effect of abrasive, adhesive, diffusive and chemical wear. Diffusive wear mainly occurred in their flank faces, but did not constitute the main mechanism of notch wear; chemical wear proved to be a key reason for notch wear at higher temperatures. Based on the aforementioned research, this paper concludes with a proposed comprehensive model for notch wear.
Horizontal-direction Inconel 718 alloy cylindrical rods were fabricated by selective laser melting (SLM) and subsequently subjected to solution or homogenization plus double aging (SA or HA) treatments. Lever arm creep tests were performed with the creep tensile axis perpendicular to the building direction of the samples with a constant stress of 650 MPa at 650 °C. Scanning and transmission microscopy and electron backscatter diffraction were used to clarify the microstructure of the SA and HA samples before and after creep. The experimental results revealed that the average grain sizes of the SA and HA samples were basically the same before creep, and larger γ′ and γ″ strengthening phases existed in the HA sample. The grains tended to grow, and the higher dislocation density within grains and lower local misorientation values close to the grain boundaries occurred in the HA sample during creep, which contributed to the longer creep rupture life in comparison with the SA sample. The fracture surfaces of the SA and HA samples displayed intergranular features, and the creep voids and micro-cracks were formed around the δ or Laves phases at the grain boundaries. The creep fracture mechanism was also discussed.
GH3625 superalloy is a key part material in the field of aviation, aerospace and chemical industry. The vacuum electron beam docking test was for GH3625 laser 3D printing plate with 4mm thickness. The microstructure and mechanical properties of welded joint under optimum welding process are analyzed. The causes of thermal crack in the heat affected zone of electron beam welding joint of nickel base superalloy were studied. The results show that the existence of low melting eutectic and composition segregation is the main cause of the hot crack. The grain size and grain boundary in the weld are measured by EDS spectrometer, and it is found that Nb elements migrate to the grain boundary during the welding process. The brittle refractory compound is formed with the residual carbon element in the substrate, which reduces the adhesion of the grain boundary and leads to cracking. The microhardness of the welded joint is a symmetrical distribution with the center line of the weld as a symmetry axis, and the whole is "M" shape. The average hardness of the welded joint is higher than the base metal.
The failure modes and the wear mechanisms operating at the tool faces, when machining Incoloy 901 with Syalon* ceramic tools, have been studied. It was observed that the tool life was controlled mainly by notching at the depth of cut and flank-face wear. A t very high speeds and feed rates fracture failure was also observed. Notching at the depth of cut was the dominant failure mode at slow speeds, and the use of various active and inert atmospheres suggests that it is caused by a chemical interaction between the chip and the tool. At high speeds, tool life was controlled by flank-face wear. The wear-mechanism analyses suggest that attrition, diffusion, and plastic deformation controlled the tool life. At slower speeds, attrition is the dominant wear mechanism, whereas at higher speeds diffusion followed by plastic deformation dominates. Where attrition occurs, either individual Syalon particles or aggregates of them are lifted off the tool faces, whereas with diffusion, transition elements (especially titanium and chromium) appear to react mainly with the primary phase (β' -crystals) causing the tools to wear.
Although a plane strain plastic analysis represents a good approximation for the central portion of a metal-cutting chip, plane stress better approximates conditions at the free edges of the chip. Therefore the metal-cutting problem is reexamined using both plane strain and plane stress simultaneously. The analysis indicates that the material at the edges of the chip will become plastic at a lower value of stress than will be required by the central constrained region and that the energy per unit volume at the edges of the chip will be greater than at the center. The consequence of these results is discussed in terms of the wear groove frequently observed on a tool under the free edges of the chip, which is particularly troublesome when machining high-temperature alloys.
In order to understand the performance of the new Al2O3 + SiC whiskers ceramic cutting tools, the basic concepts for mechanics of composite materials have to be considered: aspect ratio of whiskers, fiber volume, homogeneity, anisotropy etc… During nickel alloys machining the toughening effect of the whiskers reduces the wear resulting from micro-fracture and particles removal mechanism. The composite ceramic tools can be used from scale removal to finishing with at least the same tool life as bulk ceramic tools, furthermore a better reliability can be expected.
Machining of nickel base alloys can be made by ceramic tools with metal removal rate four times greater than carbide tools. However, among twenty ceramic grades tested, only two have a sufficient strength to be used in industrial conditions, the first is an alumina base containing 30 % titanium carbide, the second is a sialon material. Tool life has been increased four times with a special edge preparation depending on the wear mechanism, frequent breakages has been explained by different kinds of defects in ceramic structure. Then it has been shown that machining with ceramic tools at high speed has not any effect on the fatigue strength of the parts.
Einsatz von Keramischen Schneidstoffen beim Drehen von Inconel 718
- Winkler