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Cutting tool materials are high quality steels made to close compositional and physical tolerances. In service, most cutting tools are subjected to extremely high and fluctuating loads. That is, the tool materials must withstand loads for long times without breaking and without undergoing excessive wear or deformation. For a tool steel at a given h...
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In the present study, electroless nickel–boron coating was deposited on AISI 4140 steel and post-treated under two different conditions. One of the treatments was carried out under a vacuum condition at 400 °C for 4 h, and the other post-treatment was plasma nitriding in an atmosphere comprising 25% N2–75% H2, at 400 °C, for 4 h. The coated samples...
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... Ancak yüksek tokluk ve darbe dayanımına ihtiyaç duyulduğunda, konvansiyonel ısıl işlemin yanı sıra alternatif bir yöntem olan Derin Kriyojenik İşlem (DKİ) de uygulanabilmektedir. DKİ'de; metaller yüksek sıcaklıklardan (800-900°C) yaklaşık 24 saat boyunca sıvı azot uygulanarak -180°C'ye kadar düşürüldükten sonra yaklaşık 250°C'de temperleme işlemine tabi tutulabilmektedir [5,6]. ...
Bu çalışmada kırıcı sanayiinde kullanılan bimetallerin mekanik özelliklerine derin sıfır altı-kriyojenik işlemin (DKİ) etkisi incelenmiştir. Son yıllarda yüksek sertliğin yanısıra yüksek tokluk ihtiyacının da olduğu darbeli kırıcılarda bimetal kompozitler yüksek manganlı östenitik çeliklerin yerine yaygın olarak kullanılmaya başlanmıştır. Konvensiyonel ısıl işlem bimetallerde uygulanmakla beraber, çalışmamızda sıfıraltı işlemin malzemenin belirli mekanik özelliklerine etkisi ve içyapı analizi de incelenmiştir. İnceleme 800°C de tavlama, -180°C de derin sıfır altı işlem 250°C de temperleme, charpy darbe testi, optik mikroskop analizi, tarayıcı elektron mikroskop analizi, X-Ray analizini ve sertlik ölçümlerini içermektedir. Her sette 5 adet deney numunesi olmak üzere 2’şer set bimetal malzeme önce 5 saat süre ile tavlama işlemine tabii tutulmuş, ardından 24 saat sıfır altı işleme ve 3-4 saat süre ile de temperleme işlemine tabii tutulmuştur. Darbe tokluk deneyleri ve sertlik ölçümleri yapılarak karşılaştırılmıştır. Sonuç olarak derin sıfır altı işlem sonrası tokluk ve sertlik değerlerinde önemli değişimlerin ortaya çıktığı görülmekte olup, aynı zamanda temiz bir içyapı ve homojen bir bileşimin ortaya çıktığı gözlemlenmiştir. Derin Sıfıraltı İşlem+Temperleme sonrası numunelerin darbe tokluğunun sadece Derin Sıfıraltı İşlemi sonrasına kıyasla ortalama %20 arttığı ve sertlik oranlarının ise %10 azaldığı gözlemlenmiştir.
... Moreover, heat treatments are known to modify the entire bulk of material when compared to coatings which protect only the surface [3]. In particular, cryogenic heat treatment of tool steels is one of the well-known effective methods in improving dimensional stability fatigue behavior, grindability, hardness, toughness and wear resistance [4][5][6][7]. ...
... More number of size-refined secondary carbides ranging from 0.5-2.6 μm formed due to breaking of bigger precipitates can be seen predominantly along the grain boundary in the deep cryogenic treated specimens. The additional increase in wear resistance due to cryo-treatment is because of the formation of new carbide precipitates and the better distribution of these carbides in the matrix [4,9,34]. The area fraction of the precipitates is shown in figure 11(a). ...
Cryogenic treatment has been acknowledged as an effective means of extending tool life of many cutting tool materials, thus improving productivity significantly. However, the real mechanisms which guarantee better tool performance have not been very clearly understood. This work aims to study the effect the effect of different holding time during cryogenic treatment on M2 high speed steel (HSS) drills. The performance of these cryo-treated tools were compared on the basis of thrust force, surface roughness, tool wear and chip formation by drilling on AISI 316 SS. The thrust force was least at 600 rpm and the rapid deep cryogenic treated (DCT) drills had much less thrust force (45%–55% lower) compared to untreated drills. From the various parameters involved it was observed that the cryo-treated tool bit at holding time of 24 h and at a cutting speed of 600 rpm and feed rate of 0.06 mm rev⁻¹ showed better performance. The relative wear resistance of the cryo-treated drill at 24 h was at least two times better than the untreated drill while the surface roughness of the holes drilled with this drill was half that of those drilled with untreated drills. This investigation was further extended by gradual shallow cryogenic treatment (GSCT) and gradual deep cryogenic treatment (GDCT) of drills at the optimum holding time of 24 h. Both GSCT and GDCT treated drills showed 35% and 15% less thrust force respectively when compared to DCT. The better performance can be attributed to the lack of internal residual stresses. Microstructure SEM images and Rockwell hardness testing was done to support the findings.
... As enhanced hardness was owed to increase in carbide density, Dhokey et al. in 2012 [21] reported that the tertiary carbide produced during CT at the 4 h soaking time is responsible for increased wear resistance. Reddy et al. in 2015 achieved a marginal change in hardness when CT resulted in the formation of n-phase carbides instead of removal of retained austenite [22]. In 2016, Sharma and Crew did a comparative study on DCT processed high steel for secondary hardness [16]. ...
The machining industries always eye on increasing hardness and reducing the friction at the cutting tool–workpiece interface to reduce flank wear, thereby enhancing the tool life. The present study investigates the effect of deep cryogenic treatment (DCT) on the behavior of M2 HSS tool in turning of C45 medium carbon steel. The tool is double tempered and is tested for hardness and flank wear. The power consumption is also analyzed in the process with a focus on green machining. While Taguchi's L 27 orthogonal array (OA) is used to study the main interaction effect of all machining parameters, analysis of variance (ANOVA) and signal to noise (S/N) ratio are used for analysis of experimental outcomes. The study reveals that DCT has enhanced the hardness of HSS tool by 14.9%, while speed and feed were the dominating factors on the flank wear. Microstructure morphology using SEM is also discussed.
... As enhanced hardness was owed to increase in carbide density, Dhokey et al. in 2012 [21] reported that the tertiary carbide produced during CT at the 4 h soaking time is responsible for increased wear resistance. Reddy et al. in 2015 achieved a marginal change in hardness when CT resulted in the formation of n-phase carbides instead of removal of retained austenite [22]. In 2016, Sharma and Crew did a comparative study on DCT processed high steel for secondary hardness [16]. ...
The machining industries always eye on increasing hardness and reducing the friction at the cutting tool–workpiece interface to reduce flank wear, thereby enhancing the tool life. The present study investigates the effect of deep cryogenic treatment (DCT) on the behavior of M2 HSS tool in turning of C45 medium carbon steel. The tool is double tempered and is tested for hardness and flank wear. The power consumption is also analyzed in the process with a focus on green machining. While Taguchi's L
27 orthogonal array (OA) is used to study the main interaction effect of all machining parameters, analysis of variance (ANOVA) and signal to noise (S/N) ratio are used for analysis of experimental outcomes. The study reveals that DCT has enhanced the hardness of HSS tool by 14.9%, while speed and feed were the dominating factors on the flank wear. Microstructure morphology using SEM is also discussed.
... Cryogenic treatment transmits nearly 110% development of tool life. Cryo-treated tools consume less power as compared to untreated tools [5]. Under certain conditions,deepcryotreatmentwillnoteffectoncarbidetools, at that time reprocessed carbides are used [6]. ...
In the machining industry, coolant has an important role due to their lubrication,
cooling and chip removal functions. Using coolant can improve machining process
efficiency, tool life, surface quality and it can reduce cutting forces and vibrations.
However, health and environmental problems are encountered with the use of
coolants. Hence, there has been a high demand for deep cryogenic treatment to
reduce these harmful effects. For this purpose, -196 0C LN2 gas is used to improve
machining performance. This study focuses on the prediction of surface roughness and
material removal rate with cryogenically treated M2 HSS tool using fuzzy logic and
regression model. The turning experiments are conducted according to Taguchi’s L9
orthogonal array. Surface roughness and material removal rate during machining of
C45 steel with HSS tool are measured. Cutting speed, feed rate, and depth of cut are
considered as machining parameters. A model depended on a regression model is
established and the results obtained from the regression model are compared with the
results based on fuzzy logic and experiment. The effectiveness of regression models
and fuzzy logic has been determined by analyzing the correlation coefficient and by
comparing experimental results. Regression model gives closer values to
experimentally measured values than fuzzy logic. It has been concluded that
regression-based modeling can be used to predict the surface roughness successfully.
... Cryogenic treatment transmits nearly 110% development of tool life. Cryo-treated tools consume less power as compared to untreated tools [5]. Under certain conditions,deepcryotreatmentwillnoteffectoncarbidetools, at that time reprocessed carbides are used [6]. ...
Cryogenic treatment deals with heating and cooling tool piece in extreme condition so that the complete stress is relieved as to achieve zero entropy at absolute zero temperature. Exploration of the benefit of cryo-treatment for achieving improvement in wear resistance of tool steel is a topic of current research interest. This work discusses the various cryogenic treatments used so far in a manufacturing process. The optimization technique such as Taguchi method is reviewed. The present work explores the effect of cryogenic treatment done on a single point cutting tool (HSS) which helps in machining different tool materials with a better surface finish and increased tool life. Further, we propose the use of regression model and fuzzy logic based approaches for efficient optimization of process parameters. This work will act as a primer for the researchers/Industrialists and students who enter into the world of cryogenic treatment.
... Such mechanical properties and wear resistance can be obtained from the carburization and quenching processes. This manufacturing process can be characterized by the key points such as: it is applied to low carbon work-pieces, work-pieces are in contact with high carbon gas, liquid or solid, it produces hard work-piece surface, work-piece cores retain soft [1]. Carburization consist of enrichment of surface layers of low carbon / mild steel (C less than equal to 0.30%) with carbon up to 0.8 % to 1% by this way the good wear and fatigue resistance is superimposed on a tough low carbon steel core. ...
Prediction and control of undesirable deterioration of cutting tools are the most essential challenges emanating in the design of tool which has to be checked. As a result of an increase in wear rate of HSS cutting tools, so has the need for wear resistant. The result has been a progression of carburizing the tools for better performance. Based on the theoretical analysis and study of tool wear and parameters that mitigates against wear resistance of cutting tools, this research work presents an experimental investigation and analysis of the wear properties of carburized HSS cutting tools. Twelve Samples under consideration were carburized HSS (ASTM A600) tools (0.65% C) treated at 800,850,900 and 950oC with holding time of 60, 90 and 120 minutes respectively. The wear properties of weight loss, wear volume, wear resistance and wear rate were carried out using Rotopol –V, impact tester, polisher, grinder and weight scale. It was found from the experiment carried out that cutting tool(sample 5) carburized at holding temperature and time of 800 oC and 90 minutes has the lowest cutting weight loss, volume and wear rate of 0.002 g, 0.00026 cm3 and 5.476 X10-10 cm2 with maximum wear resistance of 1.83X109. This showed that sample 5 has the best wear properties which undermined the general believe that the sample with highest holding temperature and time should have the highest wear properties. This experiment has further established carburization as one of the heat treatment methods that involved carbon penetration to the depth that improved wear rate and resistance of a material.
... Such mechanical properties and wear resistance can be obtained from the carburization and quenching processes. This manufacturing process can be characterized by the key points such as: it is applied to low carbon work-pieces, work-pieces are in contact with high carbon gas, liquid or solid, it produces hard work-piece surface, work-piece cores retain soft [1]. Carburization consist of enrichment of surface layers of low carbon / mild steel (C less than equal to 0.30%) with carbon up to 0.8 % to 1% by this way the good wear and fatigue resistance is superimposed on a tough low carbon steel core. ...
Prediction and control of undesirable deterioration of cutting tools are the most essential challenges emanating in the design of tool which has to be checked. As a result of an increase in wear rate of HSS cutting tools, so has the need for wear resistant. The result has been a progression of carburizing the tools for better performance. Based on the theoretical analysis and study of tool wear and parameters that mitigates against wear resistance of cutting tools, this research work presents an experimental investigation and analysis of the wear properties of carburized HSS cutting tools. Twelve Samples under consideration were carburized HSS (ASTM A600) tools (0.65% C) treated at 800,850,900 and 950 o C with holding time of 60, 90 and 120 minutes respectively. The wear properties of weight loss, wear volume, wear resistance and wear rate were carried out using Rotopol-V, impact tester, polisher, grinder and weight scale. It was found from the experiment carried out that cutting tool(sample 5) carburized at holding temperature and time of 800 o C and 90 minutes has the lowest cutting weight loss, volume and wear rate of 0.002 g, 0.00026 cm 3 and 5.476 X10-10 cm 2 with maximum wear resistance of 1.83X10 9. This showed that sample 5 has the best wear properties which undermined the general believe that the sample with highest holding temperature and time should have the highest wear properties. This experiment has further established carburization as one of the heat treatment methods that involved carbon penetration to the depth that improved wear rate and resistance of a material.
The shallow cryogenic (subzero) treatment (SCT) effect on the mechanical properties of the bimetallic casting used in the crushing industry has been investigated. Examination methods include sand casting, heat treatment and SCT, Charpy impact test, optical microscope, scanning electron microscope, microanalysis of the chemical composition (energy dispersive spectroscopy—EDS), x-ray diffraction, and hardness measurement. Two bimetallic castings (single casting containing two layers, one of low-carbon cast steel-LCCS-back up part and other high Cr cast iron-HCCI-working part) have been prepared by the sand casting method. They have been subjected to diffusion annealing at 1040 °C for 5 h. One of them was quenched in pressurized air till 100 °C and was tempered at 270 °C for 3 h and, and the other one has been subjected to SCT at − 84 °C for 24 h and then tempered at 270 °C for 3 h. The impact toughness values before and after SCT are determined five Charpy specimens per point. Hardness values and metallography of samples have been analyzed and compared. A remarkable change was observed in hardness and impact energy/toughness before and after SCT.
The present paper compares some of the vital cut qualities of C45 alloy steel while turning operation. The effect of cryogenic treatment and machining parameters on cutting force and temperature were investigated in the dry turning of C45 steel with treated and untreated M2 HSS tool with the radial nose of 0.4mm, are optimized by using the statistical method. The selected work material was machined with untreated and deep cryogenically treated M2 HSS tools and the results were compared in order to exhibit the feasibility of DCT tools. Series of experiments were performed by adopting Taguchi's L27 orthogonal array. Cutting speed, feed rate, and depth of cut were taken as three process variables whereas cutting force (Fc), machining temperature (Tm) were selected as the machining characteristics to be compared. The cutting tool materials were initially characterized to examine the effects of deep cryogenic treatment. The characterization was done with the help of a hardness test and scanning electron microscopy (SEM) test coupled with energy dispersive spectroscopy (EDS). The result shows that the depth of cut is the most significant factor for both treated and untreated tool on cutting force, temperature followed by cutting speed and feed rate has less significance, from statistical method to obtain considerably reduced the cutting force of HSS tool by 9.11%and temperature by 11.5%, while depth of cut was the dominating factor for both.
