高碳铬轴承钢中初生碳化物尺寸的预测研究  

Prediction of primary carbide size in high carbon chromium bearing steel

作　　者：冯乾 曾亚南 李俊国 王一同 王亚军 唐国章 Feng Qian;Zeng Yanan;Li Junguo;Wang Yitong;Wang Yajun;Tang Guozhang(School of Metallurgy and Energy,North China University of Technology,Tangshan 063210,Hebei,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《钢铁钒钛》2023年第6期198-204,共7页Iron Steel Vanadium Titanium

基　　金：国家自然科学基金面上项目(52274333);国家自然科学基金联合基金项目(U21A20112);高等学校科学技术研究重点项目(ZD2019001);唐山市重点研发计划项目(19140255F);河北省研究生创新项目(CXZZBS2021097)。

摘　　要：采用Thermo-Calc热力学计算软件对轴承钢凝固过程相转变规律、初生碳化物物相类型、初生碳化物析出温度进行热力学分析。基于Scheil偏析模型和Goto模型对轴承钢凝固过程中初生碳化物粒子尺寸进行预测,并通过热模拟试验和碳化物显微形貌定量分析对预测结果进行试验验证。计算结果表明,轴承钢凝固过程初生碳化物为(Fe,Cr)C型碳化物,析出温度为1158℃。其析出行为主要是凝固末端残留液相中C和Cr元素偏析所引起的,当固相率为0.92时,残留液相中C元素的质量分数达到4.12%;残留液相中的Cr元素质量分数达到2.59%,初生碳化物尺寸为8.2μm。此外,钢液中C元素的增加可以使初生碳化物析出温度提高,初生碳化物尺寸增大。但是,凝固过程中初生碳化物的尺寸主要是由冷却速率决定的,当冷却速率由0.2℃/s增加到3℃/s时,初生碳化物最大尺寸由19.25μm减小至5.02μm,其影响机制是冷却速率增大会使初生碳化物晶体各界面附近原子扩散速率降低,使得碳化物晶体各界面各向异性生长受阻,最终导致初生碳化物尺寸减小。A Thermo-Calc thermodynamic calculation software was used to conduct thermodynamic analysis on the phase transformation,primary carbide phase type,and primary carbide precipitation temperature during solidification process of bearing steel.Based on both Scheil segregation model and Goto model,the size of primary carbide particles during solidification process of bearing steel was predicted,and the predicted results were experimentally verified through thermal simulation tests and quantitative analysis of carbide microscopic morphology.The results show that primary carbides during solidification process of bearing steel are(Fe,Cr)C carbides and its precipitation temperature is 1158℃.The precipitation behavior is mainly caused by the segregation of C and Cr in the residual liquid phase at the end of solidification.When the solid phase ratio is 0.92,the mass fraction of C in the residual liquid phase reaches 4.12%;The mass fraction of Cr element in the residual liquid phase reached 2.59%,and the size of primary carbides reached 8.2μm.In addition,the precipitation temperature of primary carbides and the size of primary carbides can be increased with the increase of solute C in molten steel.However,the size of primary carbides during solidification is mainly determined by the cooling rate.When the cooling rate is increased from 0.2℃/s to 3℃/s,the maximum size of primary carbides increases from 19.25μm reduced to 5.02μm.The influence mechanism is that increasing cooling rate will reduce the diffusion rate of atoms near the interfaces of primary carbide crystal,which will hinder the anisotropic growth of carbide crystal interfaces,and ultimately lead to decreasing primary carbide size.

关 键 词：轴承钢 初生碳化物 Goto模型 生长行为 冷却速率 溶质元素 动力学 

分 类 号：TF76[冶金工程—钢铁冶金]