摘要
针对9%Cr铁素体耐热钢试板-20℃冲击性能不合格问题,通过显微组织分析,发现主要原因是晶粒粗大或混晶。采用正火、退火及等温退火等热处理工艺进行晶粒细化研究。结果表明:两次正火可将晶粒度细化至9.5级,但均匀性较差;两次退火后仍存在马氏体/珠光体混晶;而通过730℃等温退火12 h可获得均匀细小的铁素体/碳化物组织,晶粒尺寸约20~30μm,是改善混晶组织的最优工艺。
Aiming at the problem of inadequate impact performance of the 9%Cr heat-resistant ferrite steel test plate at-20℃,this paper carries out analysis based on micro-structure of the steel and finds out that the main causes including coarse grain size and mixed grain structure.This paper carries out study on grain refinement by investigating the heat treatment processes including normalizing,annealing,and isothermal annealing.The results show that two rounds of normalizing can have the grain size refined to 9.5,but with poor uniformity;two rounds of annealing still have remaining mixed martensite/pearlite grains;with isothermal annealing under 730℃for 12 hours,uniform and fine ferrite/carbonitride structure with grain sizes approximately 20~30μm can be obtained and is proved to be the optimal process for mixed grain micro-structure improvement.
作者
何承渝
冯唯伟
He Chengyu;Feng Weiwei
出处
《一重技术》
2025年第4期19-21,53,共4页
CFHI Technology
关键词
9%Cr铁素体耐热钢
冲击性能
晶粒细化
9%Cr heat-resistant ferrite steel
impact performance
grain refinement
