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通过分段冷却实验,研究了冷却速度和等温温度对GCr15SiMn轴承钢中碳化物析出规律及C、Cr、Mn元素扩散规律的影响。结果表明:当冷却速度大于5℃/s,能够有效抑制网状碳化物出现;当珠光体相变温度在590~620℃时,既能抑制C、Cr、Mn元素向奥氏体晶界扩散,防止二次碳化物在珠光体相变过程中出现,又能形成良好的索氏体组织。当相变温度达到650℃时,二次碳化物可以在低于Ar1的温度区间随着珠光体相变析出。通过对实验数据进行线性拟合,得出珠光体片层厚度和过冷度的经验公式为SP-1=-3.81×10-3+1.166×10-4ΔT。
Through segmented cooling experiments, the effects of cooling rate and isothermal temperature on the precipitation of carbides and the diffusion rules of C, Cr and Mn in GCr15SiMn bearing steel were studied. The results show that when the cooling rate is more than 5 ℃ / s, the occurrence of network carbides can be effectively inhibited. When the pearlite transformation temperature is 590-620 ℃, the diffusion of C, Cr and Mn into the austenite grain boundaries can be suppressed , To prevent the occurrence of secondary carbides in the pearlite transformation process, but also to form a good sorbite. When the phase transition temperature reaches 650 ℃, the secondary carbides can precipitate with pearlite transformation in the temperature range lower than Ar1. By fitting the experimental data linearly, the empirical formula of pearlite sheet thickness and supercooling degree is obtained as SP-1 = -3.81 × 10-3 + 1.166 × 10-4ΔT.