【摘要】 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。更多还原

【Abstract】 Effects of cooling rates and isothermal temperature on precipitation of carbide and diffusion of C,Cr,Mn in a GCr15 SiMn bearing steel were studied.The results show that network carbide is suppressed while cooling rate is greater than 5 ℃ /s.When transformation temperature is in the range of 590 to 620 ℃,it is hard for C,Cr and Mn to diffuse from austenite interior to boundary.As a result,the network carbide can be prevented.Furthermore,sorbite microstructure is obtained in this isothermal range.When transformation temperature gets to 650 ℃,proeutectoid carbide is precipitated at the austenite boundaries although the temperature is below Ar1.On the basis of experimental results,the relationship of pearlite lamella thickness and degree of undercooling can be expressed as SP-1=-3.81 × 10-3+ 1.166 × 10-4ΔT.更多还原