Effect of Prior Cold Deformation on the Stability of Retained Austenite in GCr15 Bearing Steel

In this paper, the precipitation thermodynamics and growth kinetics of TiN inclusions in GCr15 bearing steel during solidification were calculated in more detail. A more reasonable formula for calculating the segregation of the solute elements was adopted and the stability diagram of TiN precipitation considering solidification segregation was given. By solving equations, the change of the solute element content before and after TiN inclusion precipitation was calculated, and the results were substituted into the kinetic formula of the inclusion growth, which made the kinetic calculation more accurate. Results showed that the most effective way to reduce the precipitation of TiN is to increase the cooling rate and decrease the contents of Ti and N in steel. The effect of Ti content on the size of TiN inclusions is greater than that of N content.

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Effect of Cold Ring Rolling on the Wear Resistance of GCr15 Bearing Steel after Quenching and Tempering

Metals ◽

10.3390/met9060647 ◽

2019 ◽

Vol 9 (6) ◽

pp. 647

Author(s):

Bohan Lu ◽

Wenting Wei ◽

Huajie Mao ◽

Xiaohui Lu

Keyword(s):

Retained Austenite ◽

Wear Behavior ◽

Bearing Steel ◽

Ring Rolling ◽

Wear Loss ◽

Austenite Content ◽

Gcr15 Bearing Steel ◽

Cold Ring Rolling ◽

Quenching And Tempering ◽

Carbide Content

In this work, the effects on dry wear behavior of cold ring rolling (CRR) of GCr15 bearing steel, after quenching and tempering (QT) heat treatment are investigated. The effects on steel microstructures and wear mechanisms of CRR with different austenitizing times are also discussed. The results show that, with a short austenitizing time of 10 min, CRR can increase the retained austenite content, decrease the undissolved carbide content and improve the hardness of the specimen, thus reducing ploughing and fatigue flaking, and decreasing the wear loss of the CRR specimen. With the longer austenitizing time of 20 min, the retained austenite content increases, the undissolved carbide content decreases, and the hardness increases significantly, both in specimens with and without CRR, so that ploughing, fatigue flaking, and wear loss can all be decreased. However, with an austenitizing time of less than 20 min, the effects of CRR on retained austenite content, undissolved carbide content, and hardness are not significant. Thus, CRR of less than 20 min cannot further improve wear morphology or decrease wear loss.

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Laser Surface Hardening of GCr15 Bearing Steel Ring

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.442.130 ◽

2010 ◽

Vol 442 ◽

pp. 130-136 ◽

Cited By ~ 5

Author(s):

R. Akhter ◽

A. Hussain ◽

W.A. Farooq ◽

M. Aslam

Keyword(s):

Surface Hardening ◽

Laser Power ◽

Retained Austenite ◽

Fold Increase ◽

Spot Size ◽

Bearing Steel ◽

Laser Surface ◽

Beam Shape ◽

Gcr15 Bearing Steel ◽

Cw Co2 Laser

Surface hardening of GCr15 bearing steel ring was carried out using CW CO2 laser. The laser power used was in the range of 300 to 500 Watts. A rectangular beam shape was used to cover the area to be hardened. A three fold increase in the hardness of the transformed zone was achieved. The depth of hardness attained was around 1mm. The depth and width of the laser treated zone were studied as function of laser power and working speed for specific spot size. The microstructure of the transformed zone is also discussed. Subzero cooling technique was applied to convert the retained austenite to martensite.

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