FEM prediction of retained austenite evolution in cold work die steel during deep cryogenic treatment

2013 ◽  
Vol 100 ◽  
pp. 274-277 ◽  
Author(s):  
Junwan Li ◽  
Yuan Feng ◽  
Leilei Tang ◽  
Xiaochun Wu
Keyword(s):  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Deep Cryogenic Treatment ◽  
Die Steel

scholarly journals Multiscale Analysis of the Microstructure and Stress Evolution in Cold Work Die Steel during Deep Cryogenic Treatment

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2122 ◽  
Author(s):  
Junwan Li ◽  
Xin Cai ◽  
Yiwen Wang ◽  
Xiaochun Wu
Keyword(s):  
Phase Transformation ◽  
Driving Force ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Multiscale Model ◽  
Stress Evolution ◽  
Deep Cryogenic Treatment ◽  
Mechanical Coupling ◽  
Transformation Stress

Through a combination of 3D representative volume element (RVE) and the metallo-thermo-mechanical coupling finite element (FE) analysis, a multiscale model was established to explore the localized characteristics of microstructure and stress evolution during deep cryogenic treatment (DCT). The results suggest that after cooling to near −160 °C, the largest intensity of martensite is formed, but the retained austenite cannot be eliminated completely until the end of DCT. The driving force for the precipitation of fine and uniform carbides during DCT is provided by the competition between the thermal and phase transformation stresses. Compared with the thermal stress, the phase transformation stress during DCT plays a more significant role. At the interface between retained austenite and martensite, a reduction of around 15.5% retained austenite even induces an obvious increase in the phase transformation stress about 1100 MPa. During DCT, the maximum effective stress in RVE even exceeds 1000 MPa, which may provide a required driving force for the precipitation of fine and homogeneously distributed carbide particles during DCT.

Effect of deep cryogenic treatment on internal friction behaviors of cold work die steel and their experimental explanation by coupling model

2010 ◽  
Vol 527 (29-30) ◽  
pp. 7950-7954 ◽  
Author(s):  
Shaohong Li ◽  
Lihui Deng ◽  
Xiaochun Wu ◽  
Hongbin Wang ◽  
Yong’an Min ◽  
...  
Keyword(s):  
Internal Friction ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Coupling Model ◽  
Deep Cryogenic Treatment ◽  
Die Steel

The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel

2019 ◽  
Vol 4 (1) ◽  
pp. 286-294
Author(s):  
László Tóth ◽  
Réka Fábián
Keyword(s):  
Heat Treatment ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Chromium Steel ◽  
Primary Carbide ◽  
Tempering Temperature ◽  
Tempering Treatment ◽  
Primary Carbides

The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.

Structure and Property of Sub-Zero Processed Cold Work Die Steel

2013 ◽  
Author(s):  
Debdulal Das ◽  
Kalyan K. Ray ◽  
Apurba K. Dutta
Keyword(s):  
Mechanical Properties ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Cold Treatment ◽  
Homogeneous Distribution ◽  
Tool Steels ◽  
Deep Cryogenic Treatment ◽  
Structure And Property ◽  
Conventional Heat Treatment ◽  
Processing Cycle

This study examines the influence of different sub-zero processing routes on microstructure and mechanical properties of a cold work tool steel. Incorporation of controlled sub-zero processing cycle in between hardening and tempering treatment of tool steels increases the amount of ultrafine carbide particles with improved homogeneous distribution in addition to reduction in retained austenite content; these modifications are found to be enhanced with decreasing lowest temperature of the sub-zero processing cycle. It has been demonstrated that with reference to conventional heat treatment, sub-zero processing moderately improves hardness and marginally reduces fracture toughness but substantially enhances wear resistance of the selected steel; the extent of variations, in general, increase in the order of cold treatment, shallow cryogenic treatment and deep cryogenic treatment. The relationships of microstructural modifications with the variations of mechanical properties of tool steels due to different sub-zero processing have been established.

scholarly journals Influence of Cryogenic Treatment on Wear Resistance and Microstructure of AISI A8 Tool Steel

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1038 ◽  
Author(s):  
Pello Jimbert ◽  
Maider Iturrondobeitia ◽  
Julen Ibarretxe ◽  
Roberto Fernandez-Martinez
Keyword(s):  
Wear Resistance ◽  
Tool Steel ◽  
Scientific Literature ◽  
Wear Behavior ◽  
Cryogenic Treatment ◽  
Cold Work ◽  
Secondary Carbide ◽  
Tool Steels ◽  
Deep Cryogenic Treatment ◽  
Cold Work Tool Steel

The effects of deep cryogenic treatment (DCT) on the wear behavior of different tool steels have been widely reported in the scientific literature with uneven results. Some tool steels show a significant improvement in their wear resistance when they have been cryogenically treated while others exhibit no relevant amelioration or even a reduction in their wear resistance. In this study, the influence of DCT was investigated for a grade that has been barely studied in the scientific literature, the AISI A8 air-hardening medium-alloy cold work tool steel. Several aspects were analyzed in the present work: the wear resistance of the alloy, the internal residual stress, and finally the secondary carbide precipitation in terms of lengths and occupied area and its distribution into the microstructure. The results revealed a reduction in the wear rate of about 14% when the AISI A8 was cryogenically treated before tempering. The number of carbides that precipitated into the microstructure was 6% higher for the cryogenically treated samples, increasing from 0.68% to 0.73% of the total area they covered. Furthermore, the distribution of the carbides into the microstructure was more homogenous for the cryogenically treated samples.

Effect of Cryogenic Treatment on Properties of Cr8-Type Cold Work Die Steel

2010 ◽  
Vol 17 (6) ◽  
pp. 43-46 ◽  
Author(s):  
Hong-xiao Chi ◽  
Dang-shen Ma ◽  
Qi-long Yong ◽  
Li-zhi Wu ◽  
Zhan-pu Zhang ◽  
...  
Keyword(s):  
Cryogenic Treatment ◽  
Cold Work ◽  
Die Steel

scholarly journals Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 564 ◽  
Author(s):  
Maider Muro ◽  
Garikoitz Artola ◽  
Josu Leunda ◽  
Carlos Soriano ◽  
Carlos Angulo
Keyword(s):  
Laser Cladding ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Surface Oxidation ◽  
Aging Treatment ◽  
High Hardness ◽  
Austenite Formation ◽  
Tool Steels ◽  
Deep Cryogenic Treatment ◽  
Finish Machining

Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in the die, but exhibit poor wear performance owing to the lack of carbides in their structure. This drawback can be overcome by combining laser cladding technology, austenite retention, and cryogenic treatments. Hence, an alternative die manufacturing route based on laser cladding was explored. The forming surface of a modified chemistry tool steel die was subjected to cladding. The martensite finish (Mf) temperature of the steel was tuned to enhance austenite retention at room temperature. The cladded surface was then machined in a reduced-hardness condition resulting from retained austenite formation. Subsequent deep cryogenic treatment of the die favoured the retained-austenite-to-martensite transformation, thereby increasing the die hardness without major distortion or oxidation. This process combined the advantages of high-carbide-bearing tool steels and PH steels, allowing for a die with hardness exceeding 58 HRC to be finish machined at <52 HRC. Controlling the occurrence of retained austenite represents an effective strategy for achieving new manufacturing scenarios.

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