摘要
索氏体不锈钢是一种新型不锈钢。以Cr-Ni成分体系为基础,添加Nb、Ti、Mo、Cu等元素研发出屈服强度600 MPa级的高强索氏体不锈结构钢。利用扫描电镜(SEM)、电子探针(EPMA)及透射电镜(TEM)观察了实验钢组织特征,探究了热处理工艺对其组织及力学性能的影响规律,同时对实验钢的耐腐蚀性能及强化机制进行了研究。结果表明:随着淬火温度的升高,实验钢组织不均匀性消除,原奥氏体组织及回火索氏体组织逐渐粗化;随回火温度的增加,回火索氏体组织板条宽度增大,大角度晶界比例下降;钢中主要析出相为(Fe, Cr)_(23)C相和Nb、Ti元素的碳氮化物。经950℃保温0.5 h淬火和710℃回火2 h热处理后,实验钢板综合力学性能最优,抗拉强度为856 MPa,屈服强度为668 MPa,断后伸长率20.6%,-40℃冲击功63.4 J;主要强化机制为固溶强化、细晶强化和析出强化。经360 h的模拟海水环境加速腐蚀后,平均腐蚀速率仅0.0197 mm/a,耐蚀性能优异。
Sorbite stailess steel is a new kind of stailess steel.A high strength stainless sorbite structural steel was developed with a yield strength of 600 MPa base on Cr-Ni compostion and adding Nb、Ti、Mo、Cu elements.The microstructure of the sorbite stainless structural steel and the effect of heat treatment process on its microstructure and mechanical properties were investigated by scanning electron microscopy, electron probe and transmission electron microscopy.Meanwhile, the corrosion resistance and strengthening mechanism of the experimental steel were studied. The results show that the microstructure inhomogeneity of the experimental steel was eliminated, the austenite structure and tempered sorbite structure gradually coarsened with the increase of quenching temperature. As the tempering temperature increased, the lath width of tempered sorbite structure increased and the proportion of high-angle grain boundaries decreased.(Fe, Cr)_(23)C phase and carbonitrides of Nb and Ti elements were the main precipitates in the experimental steel. The most excellent mechanical properties of the experimened steel can be obtained after quenching at 950 ℃ for 0.5 h and tempering at 710 ℃ for 2 h, where the tensile strength is 856 MPa, the yield strength is 668 MPa, the elongation after fracture is 0.6%, and the impact energy is 63.4 J at-40 ℃.Solid solution strengthening, grain refinement strengthening and precipitation strengthening were the main strengthening mechanisms.The the average corrosion rate is only 0.0197 mm/a after accelerated corrosion in a simulated seawater environment for 360 h, and the corrosion resistance is excellent.
作者
朱成林
高秀华
王明明
宋丽英
李金波
杜林秀
ZHU Chenglin;GAO Xiuhua;WANG Mingming;SONG Liying;LI Jinbo;DU Linxiu(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)
出处
《轧钢》
2022年第6期175-182,共8页
Steel Rolling
基金
辽宁省自然科学基金项目(2019-KF-25-04)。
关键词
索氏体不锈钢
显微组织
力学性能
耐腐蚀性能
强化机制
sorbite stainless steel
microstructure
mechanical properties
corrosion resistance
strengthening mechanism
