Effect of Niobium Additions on Austenite Grain Coarsening Behavior of GCr15 Bearing Steel

Abstract:

The effect of 0.018% niobium additions on austenite grain coarsening behavior of GCr15 bearing steel was studied. Results indicate that the coarsening temperatures of No.1 and the No.2 experimental steel were 950°C and 1100°C. The austenite grain coarsening temperature was increased by 150°C by the addition of 0.018% Nb in bearing steel. The grain growth equations of two experimental steels at different soaking temperatures from 850°C to 1250°C with the soaking time of 30 min are as follows: the equation of No.1 steel is D₁=1.85×10⁵·exp (-6.57×10⁴/RT); the equations of No.2 steel below and above 1100°C is D₂=5.08×10²·exp (-2.49×10⁴/RT) and D₂=1.06×10⁸·exp (-1.31×10⁵/RT), respectively. The grain growth equations of two experimental steels at different soaking time from 15 to 120 min with the soaking temperature of 840°C are as follows: the equation of No.1 steel is D₁=4.83×10^-2·t^0.72 while that of No.2 steel is D₂=1.25·t^0.18.

• Periodical: Materials Science Forum (Volume 817)
• Pages: 121-126
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.817.121
• Online since: April 2015
• Authors: Xiang Liu, Fan Zhao, Zheng Qiang Dong, Chao Lei Zhang, Yu Shan Kou, Ya Zheng Liu*
• Keywords: Bearing Steel, Grain Growth, Mathematical Model, Niobium Micro-Alloying

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