摘要
采用热膨胀仪、光学显微镜以及CM12型透射电子显微镜研究了添加0.04%N(质量分数)对00Cr13Ni4Mo马氏体不锈钢相变以及正火和回火后不锈钢组织变化的影响;通过拉伸、冲击实验和阳极极化曲线测定研究了N对正火和回火后马氏体不锈钢力学性能以及点蚀点位的影响。结果表明:1050℃正火后,N全部固溶于马氏体基体中,有效提高了实验钢的强度,同时降低了韧性;550℃以上回火后,在马氏体板条内部以及板条之间形成逆变奥氏体,有效提高了马氏体不锈钢的塑性和韧性;N抑制逆变奥氏体的形成,从而抑制了不锈钢在回火过程中的软化;同时,回火过程中,Cr2N在马氏体板条界面及内部大量析出,造成不锈钢韧性和点蚀点位下降。采用传统的正火+Ac1温度以上回火热处理工艺不利于含N马氏体不锈钢获得良好综合性能。
Effect of adding 0.04%N to 00Cr13Ni4Mo martensitic stainless steel on its solid phase transformation behavior and microstructure was investigated by means of dilatometry,optical microscopy and transmission electron microscopy（TEM）.Mechanical properties and pitting corrosion resistance of the steel were evaluated by tensile,impact and electrochemical tests.The results show that solid-solutioned nitrogen effectively enhances the strength of the steel,however,decreases its elongation and toughness after normalizing from 1050 ℃.Tempering the steel at temperatures above 550 ℃ promotes formation of retained austenite,which is reversed austenite distributed along martensitic lath boundaries and within laths,restoring the ductility and toughness of the steel.N is found to retard the kinetics of the formation of reversed austenite,thereby retarding the softening of the steel during tempering.Precipitation of Cr2N at martensite lath boundaries and within laths occurs simultaneously when the nitrogen-alloyed martensitic stainless steel is tempered at temperatures above 550 ℃,which causes the decrease in toughness and pitting corrosion potential.Traditional heat treatment of normalizing and tempering at temperature above Acl is not suitable for high nitrogen martensitic stainless steel to achieve good combined properties.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第4期77-84,共8页
Transactions of Materials and Heat Treatment
基金
辽宁省科技攻关计划项目(2007221007)
长江学者和创新团队发展计划资助项目(IRT0713)
关键词
马氏体不锈钢
氮
逆变奥氏体
析出
性能
martensitic stainless steel
nitrogen
reversed austenite
precipitation
property
