Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (1): 107-115.DOI: 10.1007/s40195-018-0787-4

Special Issue: 2019年钢铁材料专辑

• Orginal Article • Previous Articles     Next Articles

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

Feng Wang1,2, Dong-Sheng Qian1,2(), Xiao-Hui Lu2,3()   

  1. 1.School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
    2.Hubei Key Laboratory of Advanced Technology for Automotive Components, Wuhan 430070, China
    3.School of Automotive Engineering, Wuhan University of Technology, Wuhan 430070, China
  • Received:2018-04-29 Revised:2018-06-05 Online:2019-01-10 Published:2019-01-18
  • Contact: Qian Dong-Sheng,Lu Xiao-Hui
  • About author:

    Author brief introduction:Dao-Kui Xu Professor of IMR, CAS, and “Young Merit Scholar” of Corrosion Center in the Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS). He achieved Ph.D. degree from IMR, CAS, in 2008, during which he obtained “Chinese Academy of Sciences-BHP Billiton” Scholarship award, “Shi Changxu” Scholarship award and “Zhu-LiYueHua” Excellent Doctorate Student Scholarship of Chinese Academy of Sciences. He worked as a Research Fellow in ARC Center of Excellence, Design of Light Metals, Department of Materials Engineering, Monash University, Australia (2008.10-2011.10). He published more than 60 peer-reviewed scientific papers, attended 20 invited lectures and holds seven patents. His papers were cited more than 1200 times. His research interests mainly include: (1) fatigue behavior and fracture toughness of light metals, such as Mg, Al and Ti alloys; (2) effects of alloying, heat treatment and thermomechanical processes on the microstructural evolution and mechanical improvement of light metals; (3) corrosion, stress corrosion cracking and corrosion fatigue behavior of lightweight alloys; and (4) design of new lightweight alloys with a good balance of properties in terms of mechanical property and corrosion resistance.

Abstract:

In this work, the effect of prior cold deformation on the stability of retained austenite in GCr15 bearing steel was investigated after quenching and tempering treatment. The thermal stability was evaluated by calculating thermal activation energy for decomposition of retained austenite using differential scanning calorimeter. The mechanical stability was investigated according to the strain-induced martensitic transformation behavior of retained austenite under the standard compression testing. It is found that the prior cold deformation not only accelerates the carbide dissolution during the austenitization process but also contributes to the carbon partitioning in the tempering stage due to the higher density of phase boundaries, which results in the improvement of the thermal stability of retained austenite. Due to the enhanced carbide dissolution, the higher carbon content in the prior austenite will intensify the isotropic strain of martensitic transformation. As a consequence, the film-like retained austenite is likely to form under a higher hydrostatic pressure and thus shows a higher mechanical stability. Additionally, it is noteworthy that the benefits of the prior cold deformation to the stability of retained austenite would be saturated when the cold deformation degree is larger than 40%.

Key words: GCr15 bearing steel, Prior cold deformation, Retained austenite stability