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Cryogenic Treatment of Metals to Improve Wear Resistance
Abstract
Nineteen metals, including 12 tool steels, 3 stainless steels, and 4 other steels, were subjected to cryogenic treatments to determine the difference between a 189 K soak and a −77 K soak in improving the abrasive wear resistance. The tool steels exhibited a significant increase in wear resistance after the soak at 77 K and a less dramatic increase after the 189 K soak. There was an increase in the wear resistance after the cryogenic treatment for the stainless steels, but the difference between the two treatment was less than 10%. The plain carbon steel and the cast iron showed no improvement after either cryogenic treatment.
... Deep cryogenic treatment (DCT), commonly referred to as cryotreatment, is an add-on process to the conventional heat treatment (CHT) of tool/die steel [15,[21][22][23][24][25]. It consists of controlled cooling of conventionally hardened steel specimens to some selected cryogenic temperature (113-77K) and holding there for sufficiently long duration h) and then warmed back to the ambient temperature at a predetermined rate for subsequent tempering treatment [19,22,[26][27][28] Some investigators have used liquid nitrogen as the quenching medium, the most effective treatment process utilizes cold gaseous nitrogen, because problems with thermal stresses are avoided during the slower cool-down in the gas [29]. Thermal control is attained by continuous monitoring of inputs and regulating the discharge of Liquid Nitrogen into the chamber and alternating the heat. ...
... From literature [19,29,[41][42][43][44][45] it is clear that cryogenic treatment reduces the amount of retained austenite. This Transformation of retained austenite to martensite depends on the cryogenic temperature and soaking period. ...
... The wear rate reaches a minimum for a longer holding time of 36h and increases again with further holding. Barron [29] ...
Deep cryogenic treatment is an add-on process to conventional heat treatment in which material is treated at cryogenic temperature. The mechanical properties of the materials are significantly improved by Deep Cryogenic treatment. Surface integrity and dimensional stability is having greater impact on the functional performance of the tool and mechanical part during service conditions. The objective of this work is to investigate the effect of deep cryogenic treatment on the surface integrity and dimensional stability of the D2 tool steel and AA 7075 Aluminium alloy. Navy C-ring test was performed to study the distortion analysis of D2 Tool Steel and AA7075 Aluminium alloy. Results showed improvement in surface roughness in D2 Tool steel and AA 7075 Aluminium alloy. DCT have higher distortion than CHT. The distortions in DCT can be attributed to the section sensitivity of D2 Tool steel and AA 7075 Aluminium alloy.
Keywords:-Surface integrity, distortion, section sensitivity, residual stresses
... He first began to employ dry steam LiN. This made it possible for them to control the temperature of DCT [29]. Previously, the material was subzero treated by being submerged directly in a liquid nitrogen media. ...
... The results of Molinari [35] and Pellizzari [53] also confirm that there is no significant improvement in hardness of the material being treated by cryogenic treatment. Barron et al. [29] found that the hardness of materials was not affected using DCT. ...
Deep cryogenic treatment (DCT), a technique of deep subzero processing, is utilized after quenching and well preceding tempering. In DCT, the materials are subjected to a soaking period of typically 24 h at a temperature of −196 °C. The optimal soaking period varies depending on the material to be cryotreated. The microstructural characteristics and mechanical properties of ferrous and nonferrous materials are significantly enhanced using DCT resulting in improved durability and functional performance of the mechanical components. The DCT is generally performed on tool steel, stainless steel, aluminum alloys, and magnesium alloys to improve its mechanical properties. The complete transition of residual austenite to martensite and finer secondary carbide precipitation correlates with an increase in the mechanical properties of tool steel. The nonferrous materials such as aluminum and magnesium alloys showed improved mechanical properties owing to the precipitation of finer second phases in the matrix. The main objective of this review paper is to provide an overview on the history and theories of DCT, important processing parameters, and the effect of DCT on microstructure and mechanical properties of tool steel, aluminum alloys, and magnesium alloys.
... The metal is then allowed to gradually warm to room temperature. [49,50] Compared to traditional cold treatment, CT offers more favorable effects. [51] The advantages include increased cutting efficiency and strength of the alloy. ...
... The first mechanism follows CT and entails a more thorough martensite transition from the austenite phase. [50] The next mechanism is the precipitation of smaller carbide particles inside the crystalline structure. [49] However, there is some debate about which mechanism plays the primary role in these changes. ...
Nickel-titanium (NiTi) instruments have become the backbone of endodontics due to their exceptional properties, superelasticity, and shape memory. However, challenges such as unexpected breakage, poor cutting efficiency, and corrosion have prompted researchers to explore innovative surface modifications to enhance their performance. This comprehensive review discusses the latest advancements in NiTi metallurgy and their impact on rotary NiTi file systems. Various surface treatment techniques, including ion implantation, cryogenic treatment (CT), thermal nitridation, electropolishing, and physical or chemical vapor deposition, have been investigated to minimize defects, boost surface hardness, and improve cyclic fatigue resistance. Ion implantation has shown promise by increasing wear resistance and cutting efficiency through nitrogen ion incorporation. Thermal nitridation has successfully formed titanium nitride (TiN) coatings, resulting in improved corrosion resistance and cutting efficiency. CT has demonstrated increased cutting efficiency and overall strength by creating a martensite transformation and finer carbide particles. Electropolishing has yielded mixed results, providing smoother surfaces but varying impacts on fatigue resistance. Physical or chemical vapor deposition has proven effective in forming TiN coatings, enhancing hardness and wear resistance. Furthermore, the concept of surface functionalization with silver ions for antibacterial properties has been explored. These advancements present an exciting future for endodontic procedures, offering the potential for enhanced NiTi instruments with improved performance, durability, and patient outcomes.
... Cryogenic treatment for metals has been established for almost 300 years primarily for enhancing the resistance to wear and localized indentation in steels [1][2][3][4][5]. In most of the studies, liquid nitrogen is used as a cryogenic medium corresponding to a temperature of −196 • C. Another commonly used medium is dry ice (−84 • C/189 K) [5]. ...
... Cryogenic treatment for metals has been established for almost 300 years primarily for enhancing the resistance to wear and localized indentation in steels [1][2][3][4][5]. In most of the studies, liquid nitrogen is used as a cryogenic medium corresponding to a temperature of −196 • C. Another commonly used medium is dry ice (−84 • C/189 K) [5]. There has been no systematic research attempt made, and there is no such attempt available in the open literature that uses comparatively higher temperatures in the cryogenic domain to investigate the properties of materials. ...
Magnesium and its composites have been used in various applications owing to their high specific strength properties and low density. However, the application is limited to room-temperature conditions owing to the lack of research available on the ability of magnesium alloys to perform in sub-zero conditions. The present study attempted, for the first time, the effects of two cryogenic temperatures (−20 °C/253 K and −196 °C/77 K) on the physical, thermal, and mechanical properties of a Mg/2wt.%CeO2 nanocomposite. The materials were synthesized using the disintegrated melt deposition method followed by hot extrusion. The results revealed that the shallow cryogenically treated (refrigerated at −20 °C) samples display a reduction in porosity, lower ignition resistance, similar microhardness, compressive yield, and ultimate strength and failure strain when compared to deep cryogenically treated samples in liquid nitrogen at −196 °C. Although deep cryogenically treated samples showed an overall edge, the extent of the increase in properties may not be justified, as samples exposed at −20 °C display very similar mechanical properties, thus reducing the overall cost of the cryogenic process. The results were compared with the data available in the open literature, and the mechanisms behind the improvement of the properties were evaluated.
... Low-temperature treatment is generally called as either "Shoal Cryogenic treatment" at temperatures of about −85° C or "Deep Cryogenic treatment" at liquid nitrogen temperature of −196° C [5]. Cryogenic treatment is not a substitute for heat treatment, but it is a subsidiary process to conventional heat treatment before tempering [2,5]. ...
... Low-temperature treatment is generally called as either "Shoal Cryogenic treatment" at temperatures of about −85° C or "Deep Cryogenic treatment" at liquid nitrogen temperature of −196° C [5]. Cryogenic treatment is not a substitute for heat treatment, but it is a subsidiary process to conventional heat treatment before tempering [2,5]. Cryogenic treatment is an optimal method to convert retained austenite into martensite. ...
Subject to a continuing debate, cryogenic treatments of alloy steels have been arrogated to increase wear resistance and toughness of the material through the interplay of three effects: completing martensitic transformation, promoting uniform precipitation of fine carbides and imparting residual stresses within material. This study reexamines effects of various heat-treatment processes including cyclic heat treatment at (690° C) and cyclic cryogenic(Shallow) treatment at (-85° C) on microstructure and mechanical properties of Stainless steel 316L.Examination methods include Scanning electron microscopy, Micro-hardness, impact testing, wear resistance measured using the standard pin-on-disk technique. Present study confirms the cryo-treatment enhanced precipitation in the subsequent tempering of alloy-depleted carbides, and moderate improvements in wear resistance and hardness, both scaling with the cryogenic treatment time and at the cost of reduced impact resistance and corrosion resistance. Reported results and correlations provide a basis for optimizing cyclic cryo-heat-treatment of austenitic stainless steels.
... However, over time, some controversial arguments have evolved regarding the application of cryogenic treatment to tool steels. Firstly, while a majority of researchers have reported that the process improves wear resistance [126,135,136], some have reported otherwise [91]. Secondly, a group of researchers have opined that wear improvement during the process is due to the transformation of retained austenite to martensite [136,137], while others claim that the improvement is attributed to the precipitation of fine secondary carbides [127,138]. ...
... Firstly, while a majority of researchers have reported that the process improves wear resistance [126,135,136], some have reported otherwise [91]. Secondly, a group of researchers have opined that wear improvement during the process is due to the transformation of retained austenite to martensite [136,137], while others claim that the improvement is attributed to the precipitation of fine secondary carbides [127,138]. The precipitation of secondary carbides during cryogenic treatment has been attributed to the contraction of the martensite matrix leading to the segregation of the released carbon atoms near defects, which eventually transform into carbides [126]. ...
The stochastic nature of tool wear during wood machining, owing to the dynamic properties of the biological material and its dependence on various factors, has raised significant industrial and research concerns in recent years. Explicitly, the tool wear is a product of the interaction between wood properties (such as hardness, density, and contamination level) and machining parameters (such as cutting speed, feed rate, and rake angle) alongside ambient conditions (such as temperature and humidity). The objective of this review paper is to provide an overview of recent advancements in the field of wood machining. To begin with, it highlights the important role of wood properties and ambient conditions influencing tool wear. Furthermore, the paper examines the various mechanisms involved in the wood-machining process and discusses their cost implications from an industrial perspective. It also covers technological advancements in the characterization of tool wear and explores the relationship between this parameter and other machining variables. It provides critical and analytical discussions on various methods for enhancing tool wear, including heat treatment, cryogenic treatment, thermochemical treatment, coating deposition, and hybrid treatments. Additionally, the paper incorporates statistical analysis to achieve two objectives. Firstly, it aims to identify the most significant wood property that affects tool wear and establish the correlation between this parameter and wood properties. Secondly, it investigates the effect of heat treatment parameters and carbide characteristics on tool wear as well as their correlation. Lastly, the review provides recommendations based on relevant literature for prospective researchers and industrial counterparts in the field. These recommendations aim to guide further exploration and practical applications in the subject matter.
... 3. Complete transformation into a martensitic phase from the austenite phase of the NiTi alloy [35] . 4. Finer carbide particles deposition throughout the crystal lattice phase [32] . ...
... The above-mentioned mechanisms have been proposed to explain the cryogenic transformation in steel alloys [35] . The absence of carbon in NiTi alloys rules out the fourth mechanism [38] . ...
... This higher amount of required cooling decreases the M f temperature below the room temperature in the high carbon or alloyed steels. In other words, cooling the samples down to room temperature during quenching did not annihilate the retained austenite [2,3]. ...
... This increase is a result of the new carbide formation during tempering. The carbon atoms movement inside the structure is due to a highly distorted martensite structure that forces the carbon atoms to jump to the nearby defects [2][3][4][5][6]. Should the samples be austenized for longer durations, more carbides will be dissolved in the structure. ...
... As propriedades com maior relevância retratadas pela literatura relacionada à inserção da etapa de criogenia são: aumento da resistência ao desgaste [1,2,3,4,5,6], aumento da tenacidade [7], e aumento na dureza [6,8,9], este podendo ser maior para temperaturas subzero que para temperaturas criogênicas [2,3]. O tratamento criogênico é usualmente classifi cado por duas categorias: superfi cial (SCT -193 K) ou profundo (DCT -77 K) [10]. ...
... As propriedades com maior relevância retratadas pela literatura relacionada à inserção da etapa de criogenia são: aumento da resistência ao desgaste [1,2,3,4,5,6], aumento da tenacidade [7], e aumento na dureza [6,8,9], este podendo ser maior para temperaturas subzero que para temperaturas criogênicas [2,3]. O tratamento criogênico é usualmente classifi cado por duas categorias: superfi cial (SCT -193 K) ou profundo (DCT -77 K) [10]. ...
Este trabalho tem por objetivo avaliar o percentual de austenita que se retêm na matriz do aço DIN 1.4110, seguinte aos processos de têmpera e criogenia em função da alternância do intervalo de tempo entre os dois tratamentos térmicos. Para isso, amostras do aço foram tratadas termicamente em um forno de 7 estágios com atmosfera controlada e resfriamento acelerado para realização da têmpera. Definiu-se 4 intervalos diferentes entre os tratamentos térmicos: imediatamente, 6, 12 e 24 horas após a têmpera. Realizou-se o tratamento criogênico com os mesmos parâmetros em todas as amostras. Foram utilizados ensaios de dureza e metalografia a fim de caracterizar a liga e o ensaio de difração de raios X para avaliar a quantidade de austenita retida nas amostras. Os resultados obtidos apontam que o tempo de espera entre tratamentos reflete diretamente nos percentuais de austenita retida no aço. Como extremos do ensaio, obteve-se o percentual de 23,6% para criogenia feita 24 horas após o tratamento de têmpera; já para o tratamento criogênico feito imediatamente após a tempera, atingiu-se o percentual de 11,9 por cento.
... This technique uses super cooled bathing at -196°C (deep CT) or storage in proximity to such super cooled materials (dry or shallow CT) [1, 2, 5-7, 11, 13-15]. Unlike surface treatments which exclusively modify alloy surface, this method alters the entire material mass by improving the transformation extent of the martensitic phase, the precipitation of the eta particles, and the release of internal stresses of alloy as a result of CT-induced plastic transformation [2,7,11,[14][15][16]. Therefore, it might be useful for strengthening rotary endodontic files [7]. ...
... This alloy might have a greater portion of complete martensite phase compared to conventional NiTi alloys [1,11,17]. A more complete martensite transformation and an increase in the martensite-to-austenite ratio in the alloy might be one of the main mechanisms believed to be responsible for the effect of cryogenic treatment [2,11,[14][15][16]. Therefore, perhaps the production protocol of these new martensitic rotary files has made them prone to more cryogenic alterations. ...
... During this type of treatment, the material is exposed to sub-zero temperatures, which cause changes in the microstructure of the metal; in the case of stainless steels, the most obvious change is the reduction in RA, caused by its transformation to martensite [3]. The improvement in the mechanical, fatigue, and wear properties of steels obtained through DCT has traditionally been attributed to the transformation of RA into martensite [4] and the refinement of secondary carbides [5]. Recent studies, however, have also shown the importance of the deformation of martensite during martensitic transformation at low temperatures [6]. ...
A low carbon/ high chromium martensitic stainless steel, X17CrNi16-2, was heat treated using two different hardening and tempering regimes (1050 °C/480 °C or 980 °C/600 °C) — promoting either a high strength or high toughness state, respectively − and further combined with deep cryogenic treatment (DCT) at −196 °C for 24 h. Over recent years DCT has been recognized as a promising technique to improve the properties of steel, predominantly with respect to its tensile strength, toughness and wear resistance. The influence of DCT on the hydrogen embrittlement resistance of martensitic stainless steel has not yet, however, been reported.
A slow strain rate tensile test (SSRT) with simultaneous cathodic hydrogen charging was selected as the method to assess potential susceptibility to hydrogen embrittlement (HE). Relatively low-intensity hydrogen charging, utilizing a constant current density of 0.1 mA/cm2, in a non-corrosive, slightly alkaline buffer solution, led to a clear reduction in the ultimate tensile stress. This reduction, and therefore the HE susceptibility, was more pronounced in the steel with a higher strength (i.e. that subject to the 1050 °C/ 480 °C heat treatment condition). Furthermore, DCT did not appear to have any impact on the steel’s mechanical properties in the presence of hydrogen. Fractographic analysis showed clear evidence of HE in the hydrogen-charged specimens.
This paper presents results of the SSRT tests and further fractography results, and discusses the impact of conventional and deep cryogenic treatment on HE susceptibility.
... Thus, cryogenic treat-ment is effective in improving the wear resistance, and reduce the residual stresses in tool steel, as demonstrated by Firouzdor et al.(2008), and Ray and Das (2017). The initial study on cryogenic treatment was performed by Barron and Mulhern (1980), and Barron (1982). These studies were focussed on understanding the effects of cryogenic treatment on the abrasive wear resistance of wide range of ferrous alloys. ...
The present study investigates the effect of cryogenic treatment on AISI D2 and D3 tool steels. This analysis is carried out for several heat treatment cycles that follow various tempering and cryoprocessing sequences that are not analysed erstwhile. Moreover, the effect of these heat treatment cycles on wear characteristics, hardness, and microstructural features of AISI D2 and D3 tool steel is also analysed. It is demonstrated that the cryogenic treatment significantly improves the wear resistance, hardness, and retained austenitic transformation of both types of material specimens under consideration. Furthermore, it is established that single tempering after cryogenic treatment is more effective than double tempering processes carried out in different sequences. It is also revealed that the double tempering sequencing involving cryoprocessing stalls the transformation of retained austenite, leading to higher wear and low hardness in the material
... ➢ Enhance resistance to fatigue 13 ➢ Improves the machinability of aluminium and copper. ...
The effect of Deep cryogenic treatment (DCT) on the metallurgical and mechanical properties of Aluminium 6061-T6 is investigated in the present work
The test castings were solutionized at 525°C for 08 hrs and water quenched to room temperature. One set of samples were subjected to cryogenic treatment at -196°C in Cryo- treatment unit, while the other set is subjected to age hardening at 160°C for durations of 3 hrs, 5hrs and 7hrs. Again cryogenic treated specimens were subjected to age hardening at 165°C for durations of 3hrs, 5 hrs and 7hrs. All the samples were taken for Mechanical properties evaluation.
The total duration of the Cryogenic treatment cycle was 36 hrs, which includes 3hrs of cooling from room temperature to -196°C, 24hrs of holding and 09 hrs of warming to room temperature. The Cryogenic treatment was carried out in a specially designed Cryogenic unit decreased.
The alloys was subjected to deep cryogenic treatment at – 1960 C for 36hrs it was observed that the mechanical properties such as UTS, Proof stress, Hardness, Flexural strength, fatigue strength, Wear resistance increased by about 27.05%, 3.35%, 10.78%, 5.8%, 36% and % of elongation, Impact strength decreased by 23.61% and 10.56% respectively, for the Deep cryogenic treated sample.
The Deep cryogenic treated alloy was characterized by using the techniques such as optical microscopy, energy dispersive X-ray spectroscopy (EDS), XRD and Scanning Electron microscopy (SEM) to observe the changes in the micro structural features. SEM results show precipitation, better distribution of second - phase particles, and higher dislocation density in the treated alloy as compared to the untreated alloy.The treatment imparts improved hardness and strength to the alloys due to precipitation hardening and high dislocation density. Fracture morphologies of the deep cryogenic treated and the native samples were characterized by using scanning electron microscopy and it was observed that the striations were denser in the treated sample Justifying the higher fatigue strength.
... Na década de 1970, alguns processos foram realizados em ferramentas acabadas através da imersão direta em nitrogênio líquido a -196ºC, com excelentes resultados quanto ao aumento da vida útil das ferramentas. (1) Os estudos iniciados na década de 70, que estenderam a tecnologia dos tratamentos criogênicos a temperaturas até -196ºC mostraram que após processos criogênicos, as propriedades mecânicas de aços rápidos e aços para matrizes são na sua totalidade melhoradas. (2) Os processos criogênicos funcionam na verdade como uma têmpera estendida, portanto muito diferente dos conceitos de um processo extra após os revenimentos. ...
... Barron (12) experimentou o tratamento criogênico profundo em açosferramentas e observou uma redução de até 718% na taxa de desgaste. Singh, Guha e Achar (13) e Singh et. ...
... No entanto, os micromecanismos propostos para explicar os fenômenos que ocorrem com a microestrutura durante a permanência a temperatura criogênica e no aquecimento subseqüente (podendo ou não ser o revenimento) não estão claramente estabelecidos. Os principais mecanismos propostos são os seguintes: i) transformação da austenita retida em martensita; (1)(2)(3) ii) decomposição e condicionamento da martensita; (3)(4)(5) iii) precipitação (3,5) ou aumento da fração volumétrica (4,6) de carbonetos η (eta). ...
... Cryogenic treatment has been known to reduce crystal defects, resulting in crystal homogeneity due to the reduction of vacancies in the crystal lattice. [26][27][28][59][60][61] Furthermore, it has been found that the cryogenic temperature and hold time contribute to the wear resistance of materials during cryogenic treatment. 29 Therefore, this study aims to investigate the effect of cryogenic treatment on the wear resistance and microstructural changes of Hadfield steel. ...
The aim of this study was to investigate the effect of shallow cryogenic treatment on the mechanical properties and microstructural evolution of a Hadfield steel with a chemical composition of (Fe-12Mn-1.2C). An ingot was produced using casting technique and heat treated by austenitizing at 1050 °C for 1 h followed by rapid quenching to room temperature. Samples were cut from the heat treated ingot and divided into three sets: H (no further treatment), HD (5% deformation), and HDC (cryogenic treatment at −80 °C for 2 h after deformation). Microstructural characterizations were performed using optical microscopy, scanning electron microscopy, and transmission electron microscopy. X-ray diffraction was used to identify formed phases and carbides, as well as determine dislocation density, crystallite size, lattice strain value, and texture coefficient. The relationships between stacking faults and dislocation density were investigated, and the wear rate and friction coefficients of the samples were calculated. The results showed that cryogenic treatment and deformation caused mechanical twinning, transformed austenite into α′(BCT) martensite, changed the form of MC type carbides, and increased the dislocation density by approximately 50%. The stacking faults were more pronounced in the cryogenic treatment samples, and the strain value of planes calculated by XRD analysis was high in cryogenically treated samples. The wear rate of the HDC sample improved by about 20% compared to the H sample. These findings provide important insights into the structural changes of high manganese steels and can contribute to the development of new materials with improved properties.
... Cryogenic treatment, in the context of conventional materials science, involves subjecting metallic materials to sub-zero temperatures [1][2][3]. Cryogenic treatment has been used for almost 300 years and has been primarily explored to increase the hardness and wear resistance of steels [4,5]. Previous studies indicate that cryogenic treatment has the potential to increase the reliability and life of steel components by as much as four times [1,3,6]. ...
Deep cryogenic treatment has shown promise as a facile method of increasing the characteristics of many materials including alloys of iron, aluminum, and magnesium. However, there have not been any prior studies on its effect on the microstructure and thermal and mechanical properties of magnesium-based nanocomposites. In this study, a Mg/2wt.%CeO2 nanocomposite was processed using disintegrated melt deposition processing coupled with hot extrusion, followed by cryogenic treatment in liquid nitrogen for 24 h. The characterization results show increases in density (reduction in porosity), ignition temperature, compressive yield strength, compressive ductility, and microhardness. This study, for the first time, shows the significant relevance of deep cryogenic treatment in enhancing an array of properties of a magnesium-based nanocomposite that may be catalytic in improving its application spectrum.
... DCT is special by exposing the material to very low sub-zero temperatures (below -160 • C) for certain time (usually 1 day) in order to alter mate-rials´microstructure and to improve different materials´properties (corrosion and wear resistance, mechanical properties and fatigue resistance) [18,[25][26][27]. Moreover, detailed literature survey showed that there is a scarcity of studies conducted on stainless steels in combination with DCT [28][29][30][31][32][33]. Furthermore, the only study, which has tested DCT treated stainless steels for corrosion resistance was conducted by Baldissera and Delprete [30], reporting observed no difference on corrosion resistance of the selected AISI 302 stainless steel. ...
This systematic study deals with the influence of deep cryogenic treatment (DCT) on microstructure and surface properties of austenitic stainless steel AISI 304 L on different length scales and in the surface region. The study incorporates different analysis techniques, such as light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ions mass spectrometry (ToF-SIMS). DCT modifies the microstructure of treated samples through promoted precipitation of Cr7C3 carbides, induced twinning and α-martensite formation. Additionally, XPS/AR-XPS and ToF-SIMS results also provide evidence of modified oxidation dynamics of DCT samples compared to conventionally heat-treated samples with increase of the Fe-oxide fraction and lower Cr-oxide fraction in the surface oxide layer. An evaluation of oxidation states and ions distribution within the surface layer of deep cryogenically heat-treated stainless steel AISI 304 L is conducted with XPS/ToF-SIMS. These results are correlated with the microstructural changes and nitrogen diffusivity induced by DCT, which are associated with modified oxidation behaviour of AISI 304 L. These results provide further understanding of DCT dynamic on the overall microstructure and the corresponding surface behaviour.
... In addition, the retained austenite is heated or transformed under strain during use, causing dimensional changes and redistribution of stress, which may also cause cracks during grinding and finishing. At present, the main ways to reduce the amount of retained austenite are high-temperature tempering and cryogenic treatment [1][2][3][4]. Cryogenic treatment has been widely used for tools, bearings, gears, and other workpieces made of high speed-steel, hard alloys and other materials. As an example, the effect of cryogenic treatment on the wear resistance of 20CrNi2Mo steel was studied by Preciado and co-workers [5]. ...
Cryogenic treatment as a process that can effectively improve the performance of steel materials is widely used because of its simplicity and speed. This paper investigates the effects of different low temperature treatments on the microstructure and properties of 17Cr2Ni2MoVNb steel. The low temperature treatment range is divided into cryogenic treatment (CT-80), shallow cryogenic treatment (SCT-150) and deep cryogenic treatment (DCT-196), all with a duration of 1 h. The retained austenite content and the change in carbide volume fraction at 0.2 mm in the carburised layer are studied. The microhardness gradient of the carburised layer, as well as the friction coefficient and wear scar morphology at 0.2 mm, was investigated. The results show that the low temperature treatment is effective in reducing the retained austenite content and increasing the volume fraction of carbide. The lowest retained austenite content and highest carbide volume fraction were obtained for DCT-196 specimens at the same holding time. Due to the further transformation of martensite and the diffuse distribution of carbides, the microhardness and frictional wear properties of DCT-196 are optimal. Therefore, low temperature treatment can change the microstructure of the case layer of 17Cr2Ni2MoVNb steel and effectively improve the mechanical properties of materials.
... Çalışmada, kriyojenik işleme tabi tutulan En 31 rulman çeliği, klasik ısıl işlem uygulanmış çeliklerden daha fazla sertlik göstermiştir. Baron (Barron, 1982), kriyojenik işlemin, malzemelerin abrasiv aşınma direncini artırmadaki etkisini belirlemek için 12 takım çeliği, 3 paslanmaz çelik ve 4 diğer çelik olmak üzere toplam 19 farklı malzemeyi -84 °C ve -196 °C olmak üzere iki farklı sıcaklıkta kriyojenik işleme tabi tutmuştur. Çalışma sonucunda, takım çelikleri, -196 °C sıcaklıkta bekletildikten sonra aşınma direncinde önemli bir artış sergilemiştir. ...
AISI H11 steel is hot work tool steel with very high thermal shock and thermal cracking resistance. It shows superior mechanical properties and toughness under hot working conditions. The alloy composition, production technique and applied heat treatment cycles have significant effects on the ability of hot work tool steels to exhibit higher mechanical properties under service conditions. In this study, the effects of cryogenic treatment on AISI H11 hot work tool steel were investigated. For this purpose, AISI H11 steel was subjected to quenching by 1020 ° C 30 min austenization process and then tempered at 450 ° C for 2 hours. Shallow cryogenic processing (-80 ° C) and deep cryogenic treatment (- 196 ° C) were applied to these samples for 6 hours and then tempered at 450 ° C for 2 hours. The hardness measurements of the samples were performed and the wear amounts were determined. In addition, the samples were examined microstructurally and the amount of residual austenite phase in the samples was also determined.
... Hence, for productivity enhancement, cryogenic treatment is a good alternative. Barron [7] concluded that wear resistance of tool steel that exhibits retained austenite at room temperature can be increased by longer soaking of the material (more than 20 h) at a temperature of 77 K. Lal et al. [8] found that it is desirable for CT of tool steel samples without advance tempering as the life of untempered samples when cryogenically treated is more compared to the tempered and CT sample. When the sample is cryogenically treated at 93K, twenty percent extra life is achieved. ...
AISI P20 is special-purpose tool steel used to produce injection molds and casting dies which should have desired properties like higher wear resistance, toughness, and hardness. The heat-treatment is established to be a vital process for the manufacturing of any product using tool steel. As the microstructure changes incurred during the process, tool steel have a greater impact on the overall characteristics. This paper investigates the changes in microstructure and phases of tool steel by following six different heat-treatment procedures. After austenitizing temperature, tool steel are cooled at − 50 °C, − 100 °C, and − 150 °C temperature. Surface morphology and phases analysis has been carried out using SEM and XRD, respectively. The micro-hardness, impact strength, wear test, compression test are measured using the micro-hardness tester machine, charpy test machine, pin-on-disc wear test rig, and universal testing machine, respectively. It is found that hard martensitic phase is developed for direct quenched material (both in water and in LN2) giving maximum hardness and its percentage increases with an increase in the cooling rate. Sub-cooled metal with − 150 °C has higher surface hardness as compared to lower temperature processes.
... It also stated that tool fracture mainly because of insufficient cooling rate, so the optimum value for cooling rate should be near to 30 °C/h. Barron [73] had observed the effect of soaking temperature (189.15 K and 77.15 K) on the wear resistance property of M2 Steel. ...
Machining operations are very common for the production of auto parts, i.e., connecting rods, crankshafts, etc. In machining, the use of cutting oil is very necessary, but it leads to higher machining costs and environmental problems. About 17% of the cost of any product is associated with cutting fluid, and about 80% of skin diseases are due to mist and fumes generated by cutting oils. Environmental legislation and operators' safety demand the minimal use of cutting fluid and proper disposal of used cutting oil. The disposal cost is huge, about two times higher than the machining cost. To improve occupational health and safety and the reduction of product costs, companies are moving towards sustainable manufacturing. Therefore, this review article emphasizes the sustainable machining aspects of steel by employing techniques that require the minimal use of cutting oils, i.e., minimum quantity lubrication, and other efficient techniques like cryogenic cooling , dry cutting, solid lubricants, air/vapor/gas cooling, and cryogenic treatment. Cryogenic treatment on tools and the use of vegetable oils or biodegradable oils instead of mineral oils are used as primary techniques to enhance the overall part quality, which leads to longer tool life with no negative impacts on the environment. To further help the manufacturing community in progressing towards industry 4.0 and obtaining net-zero emissions, in this paper, we present a comprehensive review of the recent, state of the art sustainable techniques used for machining steel materials/com-ponents by which the industry can massively improve their product quality and production.
... It enhances the overall resistance and hardness of metal, increases its transformation from the austenitic to martensitic phase, and releases the internal stresses of metal. Metals are more exible and can better tolerate fatiguein the martensitic phase [11,12]. Thus, this technique can effectively enhance the resistance of endodontic rotary les [13]. ...
Objective: This study sought to assess the effect of cryogenic treatment on cyclic fatigue of Neoniti and Reciproc nickel-titanium (NiTi) rotary files.
This in vitro, experimental study was performed on 48 Neoniti and Reciproc NiTi rotary files (#25, 6% taper) in two subgroups with and without cryogenic treatment. The files in cryogenic subgroups were stored in liquid nitrogen chamber at -196°C for 24 h. Next, they were placed at room temperature (25°C) to gradually warm up. Stainless steel (SS) blocks were used to standardize the degree of rotation of the files. The SS blocks simulated a root canal with the negative pattern of gutta-percha with 0.08 taper, #25 tip size, and 45° canal curvature. Each endodontic file was rotated in this canal until fracture. The time until fracture was recorded by a digital chronometer. Time to fracture was used to calculate the number of rotations before file fracture as the cyclic fatigue scale.
Results: The mean cyclic fatigue resistance of both Neoniti and Reciproc rotary files in cryogenic subgroups was significantly higher than that in non-cryogenic control subgroups (P<0.05). Cryogenic treatment can significantly increase the cyclic fatigue resistance of Neoniti and Reciproc NiTi rotary files.
... Low-temperature treatment is generally classified as either ''cold treatment'' at temperatures down to about −80 °C (dry ice temperature), or ''deep cryogenic treatment'' at liquid nitrogen temperature ( −196 °C). To the best of our knowledge, the first systematic comparison of the effect of cryogenic treatment on wear resistance of steels was done by Barron (1982) who studied 12 tool steels, 3 stainless steels, and 4 other steels subjected to treatments at both −80 °C and −196 °C. He showed that tool steels exhibited a significant increase in wear resistance after treatment at −196 °C and a less dramatic increase after treatment at −80 °C. ...
Deep cryogenic treatment (DCT) has been known since the 1930s to improve hardness, fatigue resistance, and wear resistance of steel. While the effect of DCT on wear properties has been well documented, there is no consensus regarding the causal mechanisms, nor a widely accepted quantitative description of them. DCT transforms retained austenite into martensite and triggers the precipitation of fine carbides, among other things. We observed that DCT had a negligible effect on Young's modulus and the yield limit of high carbon spring steel. The observed microstructural changes (presence of specific dendritic inhomogeneities typical for inclusions of austenitic phase in non-treated specimens and homogeneous microstructure of treated ones) can serve for qualitative purposes only. However, we found that DCT led to a decrease in steel electrical resistivity which can be explained by noticeable differences between the resistivities of the martensitic and austenitic phases. We propose a micromechanical model for electrical resistivity which allows monitoring of the content of retained austenite and postulate that it can be used for other materials as well. We also observed increased resistivity after mechanical loading of the specimens, correlating with increased dislocation density caused by loading. This quantity can be used to assess the average dislocation density.
По подсчетам специалистов, количество поломок и аварий, изнашивание деталей стандартной техники при эксплуатации в условиях низких температур в 3–5 раз, а иногда в 8–10 раз больше, чем в условиях умеренного климата. Поэтому повышение качества поверхностей деталей различных машин и механизмов, работающих в условиях Арктики, является актуальной задачей. В статье разработан метод комбинированной обработки, который позволяет повысить твердость, снизить шероховатость, получить оптимальные значения остаточных напряжений и создать на поверхности регулярный микрорельеф для удерживания смазки на поверхности. Но эти свойства необходимо сохранить при воздействии температур до –50°С. Проведены исследования влияния низкотемпературных воздействий на изменение в поверхностном слое деталей после комбинированной обработки. Статья будет полезна специалистам, которые занимаются проектированием машин для работы в условиях Арктики.
Martensitic stainless steels discover wide applications due to their ideal blend of quality, hardness and wear resistance in cryogenic condition. AISI 410 martensitic stainless steel, subjected to cryogenic hardening was considered using pin on disc tests took after by metallurgical examinations using scanning electron microscopy and energy dispersive spectroscopy. The microstructure includes martensite with randomly scattered carbides in the matrix. In this paper, it is used to enhance the wear conduct investigation of martensitic stainless steel 410 by cryogenic hardening process.
The need for a more sustainable and accessible source of energy is increasing as human society advances. The use of different metallic materials and their challenges in current and future energy sectors are the primary focus of the first part of this review. Cryogenic treatment (CT), one of the possible solutions for an environmentally friendly, sustainable, and cost-effective technology for tailoring the properties of these materials, is the focus of second part of the review. CT was found to have great potential for the improvement of the properties of metallic materials and the extension of their service life. The focus of the review is on selected surface properties and corrosion resistance, which are under-researched and have great potential for future research and application of CT in the energy sector. Most research reports that CT improves corrosion resistance by up to 90%. This is based on the unique oxide formation that can provide corrosion protection and extend the life of metallic materials by up to three times. However, more research should be conducted on the surface resistance and corrosion resistance of metallic materials in future studies to provide standards for the application of CT in the energy sector.
The main objective of this investigation is to analyze the influence of DCT cycles on microstructural evolution, surface roughness, hardness and dimensional stability of AISI D2 tool steel for cutting tools and dies applications. The cryogenic quenching was done using gaseous nitrogen. The AISI D2 tool steel was subjected to two DCT cycle: DCT-I (Hardening + DCT + tempering) and DCT-II (Hardening + tempering + DCT). The dimensional stability of AISI D2 tool steel was evaluated using standard Navy C-ring test. The coordinate measuring machine (CMM) was employed for the precise measurement of Navy C-ring subjected to different DCT cycle. The surface roughness was evaluated with R a (arithmetic mean roughness) and R t (total height of roughness profile) values using surface roughness tester. The microstructural features were analyzed using optical (OM) and scanning electron microscopy (SEM). The electrical resistivity and hardness of treated samples were measured using micro-Ohm meter and Vickers microhardness tester. Results showed that AISI D2 tool steel treated with DCT-I cycle exhibited greater surface finish, hardness and dimensional stability compared to DCT-II cycle. It is mainly attributed to the greater precipitation of finer carbides and balancing of tensile-compressive residual stresses.
div class="section abstract"> This study examines the influence of cryogenic treatment on the microstructure and on the physical properties of the rapid prototype SLS material. The wear properties of the rapid prototype SLS material both before and after cryogenic treatment are studied in three phases. Phase I deals with the sample preparation through the SLS technique; Phase II involves the preliminary tests like roughness test, hardness test, SEM and wear test. Phase III is the cryogenic treatment of the sample in the setup designed. The cryogenic coolant used is Nitrogen, having a boiling point of 77 K, and the whole treatment process takes about 2 to 3 days. Phase IV deals with the testing of the cryogenically treated samples in which similar tests to that in Phase I are carried out. These results are tabulated and graphs are plotted. Furthermore, the percentage change in the hardness and wear properties of the samples are found. The cryogenic aging of the material and the effect of controlled ramp up/ramp down on the samples in the cryogenic treatment is also discussed in detail in this study. It was observed that the wear resistance of the SLS component has increased significantly after the cryogenic treatment. This was mainly due to the transformation of austenite into martensite which increases hardness of the component.
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div class="section abstract"> This research is an attempt to investigate the possibility of enhancing wear and corrosion behaviour of aluminium alloy and composites for high-temperature applications. The 319 alloys with minor additions of Ni, Ti and Fe elements using the liquid metallurgy technique, Al-Si-Cu-Mg matrix alloy (Al alloy) was obtained and it was used as a base alloy and it is reinforced with Silicon carbide (SiC), Magnesium oxide (MgO) under the following composites, namely Al alloy/3wt % MgO (AA-SRM), Al alloy/ 3wt % SiC (AA-SRS) and Al alloy/3wt %SiC-3wt % MgO (AAHRSM) using a stir casting route. The wear test was investigated under the following factors, namely constant sliding velocity 3.21 m/s, sliding distance up to 10000 m under different loadings (4.9, 9.8, 14.7, 19.62, and 24.5 N) using wear test by a pin on the disc test rig. The wear rate was calculated using the tested samples under different loadings, sliding distance, and weight concentration conditions. Morphology studies of the Aluminium alloy and composites samples and their worn surface structure were examined using SEM. Finally, the corrosion test was analyzed under various environmental conditions using the specimen immersion technique. The Al-Si-Cu-Mg alloy and metal matrix composites samples were immersed for 120 hours in the concentration 0.3M H2SO4, 3.5 weight concentration NaCl, and 0.1M NaOH solution at room temperature condition. The rate of corrosion was calculated using the weight loss method.
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This study analyzes the influence of cryogenic treatments, before the pre-tempering treatment on the microstructure, and the mechanical properties of the H13 tool steel. The H13 tool steel was subjected to the shallow cryogenic treatment SCT (at –80 °C for 24 h) and deep cryogenic treatment DCT (at –185 °C for 24 h) between hardening and pre-tempering processes (at 650 °C for 15 min). Alternatively, the tool steel was exposed only to the hardening and pre-tempering processes. The characterization of the microstructures and phase transformations of the specimens was established via scanning electron microscopy and X-ray diffraction, respectively. The mechanical behavior of the treated H13 tool steel was estimated using the Rockwell hardness and abrasive wear tests. Upon completion of the quenching treatment, the H13 tool steel presented the formation of fine, thin crystals of lath-shaped martensite, while the subsequent pre-tempering treatment formed a microstructure with wider martensite laths than the as-quenched state. The sub-zero treatments on the H13 tool steel promoted several phenomena, such as the martensitic transformation, the refinement of martensite laths, and the formation of large and fine carbides dispersed in the whole microstructure. The specimens exposed to SCT and DCT achieved an improvement in hardness values due to structural changes, which also contributed to a better wear resistance (17 and 25%, subsequently) in comparison with the tool steel exposed exclusively to the pre-tempering treatment. Meanwhile, the failure mechanisms on worn surfaces of the treated H13 tool steel were micro-cutting and pitting, which were developed during the interactions among the specimen surfaces-abrasive particles-rubber wheel.
Preclinical wear testing of joint implants has primarily focussed on the wear properties of Ultra-High Molecular Weight Polyethylene (UHMWPE) articulating on wrought/cast metals. Advancements in additive manufacturing (AM) technologies, such as laser-based powder bed fusion (LPBF), have led to the increasing use of this manufacturing method in metal articulating joint components. There is, however, still uncertainty regarding the wear properties of UHMWPE against AM metals. This study employed LPBF Co-Cr-Mo and Ti-6Al-4 V pins in articulation against UHMWPE to assess the wear of the latter. A multidirectional pin-on-plate wear testing machine was used to simulate in vivo knee joint conditions over 5 × 10⁶ cycles. Wear testing was in accordance with ASTM F732. The LPBF Ti-6Al-4 V pins underwent a thermal oxidation heat treatment to improve the material's wear properties. The state of the thermal oxide layer was investigated after wear testing by sectioning the pins and measuring the thickness of the oxide layer. Wear testing showed that UHMWPE against Co-Cr-Mo had better wear properties compared to UHMWPE on Ti-6Al-4 V. The wear properties of UHMWPE against Co-Cr-Mo and UHMWPE on Ti-6Al-4 V were within ASTM F732 requirements and comparable to those reported in the literature. The thermal oxide layer on the LPBF Ti-6Al-4 V pins showed signs of delamination after 5 × 10⁶ cycles. A small oxygen diffusion zone of 1–2 μm was argued to be the reason for the delamination.
The main objective of this investigation is to analyze the influence of deep cryogenic treatment (DCT) cycles on microstructural evolution, surface roughness, hardness and dimensional stability of AISI D2 tool steel for cutting tools and dies applications. The cryogenic quenching was done using gaseous nitrogen. The AISI D2 tool steel was subjected to two DCT cycle: DCT-I (Hardening + DCT+ tempering) and DCT-II (Hardening + tempering + DCT). The dimensional stability of AISI D2 tool steel was evaluated using standard Navy C-ring test. The coordinate measuring machine (CMM) was employed for the precise measurement of Navy C-ring subjected to different DCT cycle. The surface roughness was evaluated with Ra (arithmetic mean roughness) and Rt (total height of roughness profile) values using surface roughness tester. The microstructural features were analyzed using optical (OM) and scanning electron microscopy (SEM). The electrical resistivity and hardness of treated samples were measured using micro-Ohm meter and Vickers microhardness tester. Results showed that AISI D2 tool steel treated with DCT-I cycle exhibited greater surface finish, hardness and dimensional stability compared to DCT-II cycle. It is mainly attributed to the greater precipitation of finer spherical carbides and balancing of tensile-compressive residual stresses. 1.0 Introduction Application of stronger and tougher high-performance materials, such as high carbon high chromium tool steel, is required due to the constant push for increased service performance, working efficiency, and decreased cost of service repair and maintenance for cutting tools and dies. These materials must be able to be heat treated satisfactorily to provide good hardness and dimensional stability to meet the specifications for the design and production of cutting tools and dies. AISI D2 Tool steel has been chosen as the material for this study. It is primarily used for cold working metals and is a high carbon, high chromium tool steel [1]. It contains up to 2% of carbon and 12% of chromium respectively. It possesses high wear and abrasion resistant properties. The high wear resistant and toughness properties are due to the addition of 2 Vanadium up to 0.90% [2]. It is heat treatable and will offer a hardness in the range 55-62 HRC and is machinable in the annealed condition. AISI D2 tool steel is delivered in annealed condition to make machining easier. Its structure consists of primary carbides distributed across a soft ferritic matrix, together with secondary carbides of vanadium and chromium [3]. Due to its excellent alloying qualities, AISI D2 tool steel is superior to AISI D3 tool steel. For tools and dies with very high wear resistance along with moderate hardness, AISI D2 tool steel is advised (shock-resistance). It is used to develop gauges, punches, drawing dies, blanking dies, shear blades, and cutting tools [4]. The martensite starts and finish characteristic temperatures of tool and die steels are lowered by the presence of high carbon and high alloying elements; the latter is substantially below the ambient temperature for commercial tool and die steels [5]. Therefore, the typical hardening treatment of these steels frequently results in an undesirable degree of residual austenite (Rγ) in the as-quenched structure of these steels by failing to convert a sizable amount of austenite into martensite. Being soft, the Rγ has a negative impact on desirable qualities including hardness and wear resistance [6]. Additionally, under the service conditions of tool/die steels, R is unstable and turns into martensite. Being untempered, newly generated martensite is exceedingly brittle and unattractive [7]. By putting the hardened steel specimens through several tempering cycles at a substantially higher temperature and/or for a longer period, the amount of Rγ can be decreased during traditional heat treatment [8]. However, this technique has a built-in flaw since it causes excessive matrix softening and coarsening of carbides, which lowers their hardness and strength [9]. Therefore, reducing or eliminating Rγ during the heat treatment of tool/die steels is one of the main issues. To give AISI D2 tool steel desired mechanical properties, heat treatment is utilised. It entails a quenching stage that causes unwanted tensile residual stress in the heat-treated workpiece and causes significant distortion in cutting tools and dies [10]. AISI D2 tool steel's surface integrity is also affected. Surface qualities have a significant impact on a work material's functional performance, including fatigue strength, corrosion rate, fracture toughness, and tribological behaviour including friction, wear, lubrication, and dimension accuracy [11]. Additionally, the volume expands by around 4% as austenite transforms into martensite, which results in dimensional changes, component distortion, and in severe circumstances, component failure [12]. In the design, production, and use of tooling, the distortion that results from the heat treatment is crucial [13]. Size and shape distortions are the distortions experienced during the quenching [14]. Shape distortion involves changes in its geometrical shape, while Size distortion covers changes in linear or volumetric dimensions brought on by expansion or 3 contraction [15]. The functional performance of heat-treated items is influenced, which results in production and financial losses. Inadequate surface integrity and distortion of heat-treated work pieces can lead to an expensive rise in scrap rates. Hence, the problem statement is to control the tensile residual stresses induced after quenching and minimize the retained austenite content in AISI D2 tool steel. This is necessary to improve the dimensional stability and surface
The effects of different heat and cryogenic treatments on the mechanical and tribological properties of 316L stainless steel formed by selective laser melting were investigated. The mechanical properties of samples processed by heat treatment, cryogenic treatment, and a combination of heat and cryogenic treatment were compared. It was found that the samples treated by (600°C × 3 h) + (−196°C × 24 h) exhibited better mechanical properties and the best strength and plasticity, with a tensile strength of 585 MPa and elongation of 68.5%. The experimental results of friction and wear showed that the sample treated by (600°C × 3 h) + (−196°C × 24 h) exhibited a low friction coefficient of about 0.7 and a wear amount of 2.8 × 10−3 mm3, indicating that the material has strong wear resistance.
The influence of deep cryogenic treatment (DCT) on carbides precipitation and isothermal softening behaviour as a function of both temperature and time during tempering of H13 steel was investigated. The results show that the retained austenite transformed into martensite leading to an increase in hardness. The carbon content of martensite decreased after DCT and tempering according to the calculation of the X-ray diffraction spectrum. This indicates that more fine carbides precipitated from the martensitic matrix after DCT. The morphology of microstructure and distribution of carbides have verified the properties improvement mainly depending on the retained austenite transformation and more fine carbides precipitated after tempering. In addition, the carbides precipitating and coarsening are the main causes of thermal softening.
Makine konstrüksiyonunda kullanılacak parçaların aşınma, yorulma ve korozyon dirençlerinin yüksek olması önem taşımaktadır. Hastelloy C-22 süperalaşımı yüksek korozyon direnciyle dikkat çekmekte fakat aşınma dayanımının yetersizliği nedeniyle konstrüktif kullanımı sınırlı kalmaktadır. Bu çalışmada, Hastelloy C-22 süper alaşımına, aşınma direncini iyileştirebilmek amacıyla derin ve sığ kriyojenik işlem uygulanmıştır. Aşınma deneyi öncesi metalurjik karakterizasyon amacıyla XRD analizleri, sertlik ölçümü ve mikroyapı görüntülemesi yapılmıştır. Kriyojenik işlem uygulanmış numuneler, kriyojenik işlem uygulama sıcaklıklarında 24’er saat bekletildikten sonra oda sıcaklığına 6 saatlik bir sürede getirilmiştir. Oda sıcaklığına getirilen numunelere 200 ºC ‘de 2 saat süreyle temperleme işlemi uygulanmıştır. Isıl işlem sonrası yapılan sertlik ölçümlerinde, derin kriyojenik işlem uygulanmış numunenin sertlik değerinin %45 oranında, sığ kriyojenik işlem uygulanmış numunenin sertlik değerinin ise %14 oranında arttığı tespit edilmiştir. Aşınma deneyleri ASTM G133 standartına göre doğrusal olarak ileri geri hareket eden pim üzeri plaka (ball-on flat) tipi metoduyla, tüm numunelere 10 N, 20 N ve 40 N kuvvet uygulanarak 72 mm/s sabit kayma hızında toplamda 1000 m kayma mesafesinde gerçekleştirilmiştir. Aşınma deneyleri sonucunda, sığ kriyojenik işlemde %24, derin kriyojenik işlemde ise %44 oranında hacimsel kayıp gerçekleşmiştir.
Cryogenic treatments represent an innovative technology developed with the aim of improving the performance of metallic alloys. The beneficial effects on steels are well documented in the literature, whereas their influence on other materials, such as aluminum alloys, is still not completely clarified. Even if the scientific literature reports conflicting data and conclusions, the industrial applications of such treatments are constantly growing. In the present experimental work, the mechanical and corrosion properties of a high-performance 7050 aluminum alloy were studied after cryogenic treatment at − 196°C in liquid nitrogen. Whereas no appreciable variation was observed in the mechanical resistance, the corrosion tests showed a positive effect of the cryogenic treatment. The microstructure was investigated by FEG-SEM analysis, revealing a different distribution of precipitates near the grain boundaries, which was able to reduce the electrochemical potential difference among these regions and the center-grain.
This chapter describes the behavior of NiTi at subcooled temperatures as well as at cryogenic temperatures. The requirements and the influencing parameters are discussed along with its advantages and limitations.
ASM Handbook, Volume 4A is the first in a series of five ASM Handbook volumes covering heat treating. This volume includes 50 articles that address the physical metallurgy of steel heat treatment and thoroughly cover the many steel heat treating processes. Fundamentals of hardness and the use of hardenability as a selection factor are discussed as are the fundamentals of quenching and quenching processes. The volume also discusses annealing, tempering, austempering, and martempering as well as cleaning, subcritical annealing, austenitizing, and quench partitioning. It also presents practical information on surface hardening by applied energy, carburizing, carbonitriding, nitriding, and diffusion coatings. For information on the print version of Volume 4A, ISBN 978-1-62708-011-8, follow this link.
Cryogenic-treated inserts (CTIs) are playing a vital role in the significant improvement of tool life and the enhancement of mechanical properties of the cutting tools during conventional machining process. This work addressed the upshot of cryogenic treatment of physical vapor deposition TiAlN/NbN-coated carbide insert on the machinability of a Ti-6Al-4V alloy workpiece. It is weighed in terms of surface roughness, chip morphology, and tool wear in the cutting tool insert. Surface roughness was measured by a noncontact type 3-D laser scan microscope system. The observed average surface roughness in CTI reduction is between 13 and 32 % over that of the untreated insert (UTI) machining condition. The multisurface chip characteristics of free surface and back surface were identified and broken down by scanning electron microscopy. The experimental results demonstrated that the favorable chips and the reduction in tool wear were better achieved under the CTI machining condition than under the UTI machining condition.
In this research work, two types of cryogenic treatment such as deep cryogenic treatment (-196oC) and shallow cryogenic treatment (-80oC) have been adopted for wear resistance to increase in AISI 440C bearing steel. This paper has been focused to increase Wear Resistance (WR) through deep micro structural analyses, and also attention has been made to correlate the microstructure with the wear character of Deep Cryogenic treated (DCT) specimens, Conventional Heat Treated (CHT) specimens and Shallow Cryogenic Treated (SCT) specimens. Micro structural examinations have been carried out in the specimens through Scanning Electron Microscopy (SEM), Energy Dispersive Analysis of X-ray (EDAX) and X-Ray Diffraction (XRD). Wear characteristics of AISI 440C bearing steel has been studied. The outcome of the research disclosed that the DCT specimens have higher wear resistance than SCT and CHT specimens. The effective wear mechanisms recognized were the constitution of white layers and delamination of white layers. The microstructures of the materials have been varied through heat treatment process. The modification of Secondary Carbides (SCs) precipitation characteristics and its reduction of retained austenite in the microstructure have been correlated with wear character and these are the liable mechanism to raise the wear resistance of bearing steels through DCT.
Two high-precision gauges (Ø162-Go and Ø162-Not Go) for assessing shaft components with a nominal diameter of 162 μm were machined from SKD11 steel and heat-treated using some technologies, such as quenching, cryogenic treatment, and aging, to improve hardness, wear resistance, and dimensional stability. The hardness, abrasion intensity, microstructure, phase analysis, and change in size of the gauge were observed using a Metrolog hardness tester, the pin on disc abrasion equipment, Axiovert microscopy, X-Ray Diffraction X pert PRO, and 3D measurement FUSION 9106 machine, respectively. Results showed that the hardness of gauges is approximately 62 HRC after quenching at 1030 °C for 90 min and reduces to around (59 ÷ 59,5) HRC after applying heat treatment technology in M0 mode (quenching and aging at 150 °C for 48 h). The hardness of gauges is nearly (62.5 ÷ 63) HRC, which is 2 HRC higher than the value in M1 mode (quenching + cryogenic treatment at − 80 °C/6 h + aging at 150 °C/48 h), after deep cryogenic treatment at − 160 °C in M2 mode (quenching + cryogenic treatment at − 160 °C/6 h + aging at 150 °C/48 h) due to carbides formation. The gauge after heat treatment in M2 mode demonstrated the smallest change in size (ΔL < 3 μm) in the temperature range of 20 °C–40 °C compared with M0 and M1 modes.
Previous investigations [1,2] have considered cryogenic metal treatment to improve the resistance of the material to wear and extend the useful life of machine parts. Service tests on several machine elements indicated that significant increases in part life could be achieved by soaking the part in liquid nitrogen temperatures (77 K) for several hours. Table I gives a summary of these results, showing that cryogenic treatment improved the wear resistance. There is little information in the literature, however, from which the wear improvement can be predicted quantitatively.
Measurements have been made of the abrasive wear rates of metals being slid together while their interface was provided with copious amounts of powdered abrasive (3-body abrasion). The quantitative relations between the wear rates and time of sliding, material hardness and abrasive grain size were determined, and found to be similar to those prevailing during 2-body abrasion,i.e., during the sliding of metals against abrasive-covered paper. The effects of moisture and of abrasive flow rate were investigated, and good reproducibility was found when these two variables were controlled.A simple quantitative expression for abrasive wear rate is developed, and the abrasive wear data of a number of earlier investigators is analysed in terms of this expression. Abrasive wear rates during 3-body abrasion are about 10 times less than during 2-body abrasion, probably because the average loose abrasive grain spends 90% of its time rolling and only 10% of its time abrading the sliding surfaces between which it is situated.
The four principal types of mechanical wear, namely, adhesive, abrasive, corrosive and surface fatigue, as well as several minor types are described. Quantitative equations are derived in three cases relating the amount of wear material removed from the surfaces or their useful life to operating conditions such as distance of travel, speed, applied load and mechanical properties of the surface. These equations are compared with experiment, where such exists, and agreement is found in general to be good over certain ranges although more carefully controlled experiments are needed. Hence the relations may be used by the designer and engineer in designing and constructing equipment having moving parts in which wear will be encountered.ZusammenfassungDie vier Haupttypen des mechanischen Verschleisses werden beschrieben, dies sind: Adhäsionsverschleiss (Verschweissung), Abrieb, Korrosionsverschleiss und Oberflächenermüdung, einige weniger häufige Verschleisstypen werden ebenfalls besprochen. Für jeden dieser Typen werden Gleichungen abgeleitet, die eine quantitative Beziehung legen zwischen einerseits der Menge des von der Oberfläche abgeschlissenen Materials oder der Lebensdauer und anderseits den Versuchsbedingungen so als der abgelegte Weg, Geschwindigkeit, Belastung und mechanische Eigenschaften der Oberfläche.Diese Formeln werden mit Experimenten, insofern solche zur Verfügung stehen, verglichen. Es zeigt sich, dass innerhalb gewisser Grenzen die Übereinstimmung im allgemeinen gut ist, genauere Versuche sind jedoch noch nötig. Diese Gleichungen sind daher brauchbar für Entwerfer und Ingenieure, die Maschinenteile mit bewegenden Elementen, an denen Verschleiss auftreten wird, konstruieren und bauen.