Effect of Heat Treatment Processing Parameters on the Microstructure and Properties of Low-Carbon Cr-Ni-Mo Carburizing Bearing Steels

2015 ◽  
Vol 817 ◽  
pp. 231-237 ◽  
Author(s):  
Nan Zhang ◽  
Mao Sheng Yang ◽  
Shi Qing Sun

The low-carbon Cr-Ni-Mo carburizing bearing steel was tested with different heat treatment processes. Quenching-tempering temperature and cryogenic treatment (-73°C) wasstudied respectively onthe mechanical properties and microstructure.Results show thatthe increase of quenching temperature causes the micron-sized Cr-rich carbide re-dissolution and smaller quantity of retained austenite, makingthe strength and hardness of the tested steel increase and the impact toughness decrease. The tempering temperaturerising causesthe reduction of micro-residual stresses and smallerdegree of lattice distortion andlower dislocation density, resulting in the decrease of strength and the increase of impact toughness. Cryogenic treatment contributes to the refinement of martensite lath and precipitation of nanosized carbide and lowest quantity of retained austenite, improving the strength and impact toughness of the steel.The good comprehensive mechanical propertieswith the hardness of HRC41.3, tensile strength of 1413MPa,yield strength of 1168MPa, and impact toughness of 162J/cm2 can be obtainedby optimizing the heat treatment process parameters.

2020 ◽  
Vol 993 ◽  
pp. 520-525
Author(s):  
Xiang Tao Deng ◽  
Xiao Lin Li ◽  
Long Huang ◽  
Zhao Dong Wang

The control of the retained austenite in Fe-3.0%Mn Low carbon steel by a three-step intercritical heat treatment and the low-temperature impact toughness evolution during the process were analyzed in the present study. The results indicated that the microstructure consisted intercritical ferrite, martensite/bainite and retained austenite. The distribution of carbon and manganese could improve the stability of the austenite located at the grain boundaries of prior austenite and lath boundaries of martensite. For the TRIP effect of the austenite, the excellent plasticity and low temperature toughness was obtained. The impact toughness could reach 200 J (impact energy) at -80 °C during the three-step heat treatment, and the uniform elongation could exceed at 16%.


Author(s):  
Pengjun Cao ◽  
Yilong Zhang ◽  
Kejian Li ◽  
Jiling Dong ◽  
Wei Wu

Abstract The 25Cr2MoVA steel was subjected to various heat treatments. We found that the hardness increased when the quenching temperature was in the range of 870 – 910 °C, and then it decreased for the temperature of 910 – 990 °C. The maximum hardness was 553 HV after quenching from 910 °C. Following quenching from 910°C, the 25Cr2Mo-VA steel was tempered in the temperature range of 560 to 750 °C. With an increase in the tempering temperature, the hardness and tensile strength of the material decreased, while the impact toughness increased; the corrosion resistance increased initially and then decreased. The best heat treatment process for the 25Cr2MoVA steel involved quenching form 910 °C and tempering at 650°C for 1 h, the hardness was 362 HV, the tensile strength reached 1 310 MPa, the impact energy reached 149 J, and the material exhibited the best corrosion resistance.


2015 ◽  
Vol 817 ◽  
pp. 472-478
Author(s):  
Jun Ru Li ◽  
Chen Gong ◽  
Le Yu Zhou ◽  
Lie Chen ◽  
Hui Zuo ◽  
...  

In this work, the effects of final heat treatment including quenching and tempering process on mechanical properties of 10Cr12Ni3Mo2VN steel were investigated by orthogonal experimental. It is shown that, the quenching process had a small effect on the strength properties. But the impact property obviously decreased with the increase of quenching temperature, that is due to the grain coarsening. It can be found that tempering temperature is the major factor which affects the mechanical properties. Tempering process had a large effect on the precipitation of carbides and that affected the strength, toughness and plastic greatly. The impact toughness had a minimum after tempered at 650°C between 600°C~700°C. The experimental results show that the M23C6 type carbides precipitated at the grain and martensite lath boundary were the main reason which decreased the impact toughness when tempering temperature increased from 600°C to 650°C.


2019 ◽  
Vol 4 (1) ◽  
pp. 286-294
Author(s):  
László Tóth ◽  
Réka Fábián

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.


2019 ◽  
Vol 9 (20) ◽  
pp. 4231
Author(s):  
Oskari Haiko ◽  
Antti Kaijalainen ◽  
Sakari Pallaspuro ◽  
Jaakko Hannula ◽  
David Porter ◽  
...  

In this paper, the effects of different tempering temperatures on a recently developed ultrahigh-strength steel with 0.4 wt.% carbon content were studied. The steel is designed to be used in press-hardening for different wear applications, which require high surface hardness (650 HV/58 HRC). Hot-rolled steel sheet from a hot strip mill was austenitized, water quenched and subjected to 2-h tempering at different temperatures ranging from 150 °C to 400 °C. Mechanical properties, microstructure, dislocation densities, and fracture surfaces of the steels were characterized. Tensile strength greater than 2200 MPa and hardness above 650 HV/58 HRC were measured for the as-quenched variant. Tempering decreased the tensile strength and hardness, but yield strength increased with low-temperature tempering (150 °C and 200 °C). Charpy-V impact toughness improved with low-temperature tempering, but tempered martensite embrittlement at 300 °C and 400 °C decreased the impact toughness at −40 °C. Dislocation densities as estimated using X-ray diffraction showed a linear decrease with increasing tempering temperature. Retained austenite was present in the water quenched and low-temperature tempered samples, but no retained austenite was found in samples subjected to tempering at 300 °C or higher. The substantial changes in the microstructure of the steels caused by the tempering are discussed.


2013 ◽  
Vol 820 ◽  
pp. 15-19
Author(s):  
Xiao Dong Du ◽  
Zi Li Song ◽  
Yi Qing Chen ◽  
Jia Qing Wang ◽  
Guang Fu Liu ◽  
...  

This paper describes the influence of heat treatment process on the microstructure and properties of a new martensitic stainless steel, which contains 0.7% carbon, 17% chromium and 1% molybdenum and can be used as kitchen knives and scissors. The microstructure and properties of the tested alloys after quenching at 980 - 1100 °C and low tempering were investigated by means of optical microscope (OM), scanning electron microscope (SEM), Rockwell hardness tester and impact tester. The results show that the microstructure consists of acicular martensite, carbides and a litter retained austenite after quenching and tempering. The carbides are mainly (Fe,Cr)23C6. The content of retained austenite increases with the increase of the quenching temperature. The solubility of carbon in martensite changes similarly. The martensite gets coarser as the quenching temperature increasing. The maximum value of hardness is 59 HRC, when the quenching temperature is 1060 °C. The impact toughness increases when the quenching temperature increases from 980 °C to 1080 °C and then decreases. The suitable heat treatment process for this alloy is quenching at 1060 °C~1080 °C for 30 min and then tempering at 200°C.


2010 ◽  
Vol 146-147 ◽  
pp. 1009-1012 ◽  
Author(s):  
Ji Wen Li ◽  
Guo Shang Zhang ◽  
Shi Zhong Wei

A new wear resistance material named the hypoeutectic high carbon Fe-B cast steel with fine hard carbides dispersive distributed in the matrix have been investigated. The results show that the solidified structures of high carbon Fe-B steel consist of ferrite, pearlite and boride, and borides were distributed along grain boundary in interconnected network. After heat treatment, the metallic matrix changes into martensite and retained austenite. The eutectic borides are appeared to be less continuous network and isolated particles. The increasing of the quenching temperature leads to the improvement of hardness. Quenching at 980°C, impact toughness is increased with the increasing of the tempering temperature. The optimum heat treatment is quenching at 980°C(oil cooling) and tempering at 330°C(air cooling). The wear resistance of modified high carbon Fe-B cast steel is corresponding to Cr26 alloy. The impact wear mechanism is mainly plastic deformation and fatigue spalling.


2016 ◽  
Vol 843 ◽  
pp. 248-252
Author(s):  
D.A. Mirzaev ◽  
A.N. Makovetskii

The paper considers the effect of low-carbon pipeline steels initial condition on their mechanical properties and structure after quench hardening at different temperatures in the intercritical temperature range Ac1–Ac3 (ITR) followed by tempering at 600 °C. If the prior heat treatment is annealing or normalizing , which produces the ferrite-pearlite structure, then quenching from temperatures just above Ac1 causes very strong embrittlement due to the formation of a high-carbon austenite film at ferrite/pearlite boundaries. Increasing quenching temperature in the intercritical range increases impact toughness and ductile fracture fraction for both types of prior treatment, though normalizing provides higher impact toughness than annealing. On the contrary, if the prior heat treatment is quench hardening, then the highest impact toughness is observed when the second quenching temperature lies a little above Ac1. Impact toughness and ductile fraction for preliminarily quenched samples gradually decreases along with the increase in austenitization temperature in the intercritical range.


2013 ◽  
Vol 712-715 ◽  
pp. 98-101
Author(s):  
Hong Bo Li ◽  
Jing Wang ◽  
Han Chi Cheng ◽  
Chun Jie Li ◽  
Xing Jun Su

This paper mainly through the experimental study on the heat treatment process and mechanical properties of cast steel 35CrMnSiMo.According to the effect of alloy elements in design of a high-toughness abrasion-resistant cast steel, Cr, Mn, Si, as the main alloy elements, supplemented by a small amount of Mo, the casting molding, for hardness and impact toughness test of mechanical properties of experimental steel. The results show that, the as-cast 35CrMnSiMo by 880 °C, quenching for 20min then, the same quenching temperature, quenching hardness of materials is far greater than the oil quenching hardness. Water quenching hardness up to 25% higher than the oil quenching hardness, The impact toughness of specimen is inversely proportional to the contrast relationship Hardness.


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