Y12Cr18Ni9Cu易切削钢的平衡凝固相变与MnS析出行为  

Transformations of Y12Cr18Ni9Cu free-cutting steel and precipitation behavior of MnS during equilibrium solidification

作　　者：王英虎 郑淮北 刘庭耀 宋令玺 白青青 Wang Yinghu;Zheng Huaibei;Liu Tingyao;Song Lingxi;Bai Qingqing(Chengdu Advanced Metal Material Industry Technology Research Institute Co.,Ltd.,Chengdu Sichuan 610000,China;State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan Liaoning 114009,China;National Center for Materials Service Safety,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]成都先进金属材料产业技术研究院股份有限公司,四川成都610000 [2]海洋装备用金属材料及其应用国家重点实验室,辽宁鞍山114009 [3]北京科技大学国家材料服役安全科学中心,北京100083

出　　处：《金属热处理》2023年第2期62-66,共5页Heat Treatment of Metals

摘　　要：采用Thermo-Calc热力学软件对Y12Cr18Ni9Cu易切削钢在500~1800℃的析出相进行了热力学计算并得到了平衡凝固相变路径图。结果表明,Y12Cr18Ni9Cu易切削钢的平衡相主要有MnS、液相、δ-铁素体、奥氏体、M_(23)C_(6)、M_(2)(C,N)、σ相。平衡凝固和冷却相变路径:液相→液相+MnS→液相+δ-铁素体+MnS→液相+δ-铁素体+MnS+奥氏体→δ-铁素体+MnS+奥氏体→MnS+奥氏体→MnS+M_(23)C_(6)+奥氏体→MnS+M_(23)C_(6)+奥氏体+M_(2)(C, N)→MnS+M_(23)C_(6)+σ相+奥氏体+M_(2)(C, N)。随着S含量增加,MnS的析出量逐渐增加,析出温度也逐渐升高,Mn含量变化对MnS相的析出量几乎没有影响,但Mn含量增加会使MnS析出温度升高。Y12Cr18Ni9Cu易切削钢中的硫化物呈球形、椭球形、纺锤形或短棒状并以簇状沿晶界分布,属于第Ⅱ类硫化物,长宽比≤3的硫化物占比达到了88.37%,硫化物的形态控制取得了较好的效果,有助于材料切削性能的提升。Thermo Calc thermodynamic software was used to calculate the precipitation phase of Y12Cr18Ni9Cu free-cutting steel in the temperature range from 500 ℃ to 1800 ℃, and the equilibrium solidification transformation path diagram was obtained. The results show that the main equilibrium phases in the Y12Cr18Ni9Cu free-cutting steel are MnS, Liquid, δ-Ferrite, Austenite, M_(23)C_(6), M_(2)(C, N) and Sigma. The equilibrium phase transition path is as follows: Liquid→Liquid+MnS→Liquid+δ-Ferrite+MnS→Liquid+δ-Ferrite+MnS+Austenite→δ-Ferrite+MnS+Austenite→MnS+Austenite→MnS+M_(23)C_(6)+Austenite→MnS+M_(23)C_(6)+Austenite+M_(2)(C, N)→MnS+M_(23)C_(6)+Sigma+Austenite+M_(2)(C, N). With the increase of S content, the precipitation amount and precipitation temperature of MnS gradually increase. The change of Mn content almost has no effect on the precipitation amount of MnS, but increasing Mn content will increase the precipitation temperature of MnS. The sulfides in the Y12Cr18Ni9Cu free-cutting steel are spherical, ellipsoidal, spindle shape or short-bar-like, and distribute in clusters along the grain boundary, belonging to a type II sulfide. The proportion of sulfides with length-width ratio ≤3 reaches 88.37%, and the sulfide morphology control has achieved good results, which is helpful to improve the cutting performance of the materials.

关 键 词：THERMO-CALC软件 硫化物 Y12Cr18Ni9Cu易切削钢 热力学计算 平衡凝固 

分 类 号：TG142.71[一般工业技术—材料科学与工程]