摘要
采用热膨胀仪测量了150μm和20μm大小两种晶粒尺寸的SDP1贝氏体钢的过冷奥氏体连续冷却转变(CCT)曲线,结合组织观察、硬度测试、热力学计算及动力学分析研究了晶粒尺寸对相变过程组织和硬度的影响。结果表明,小晶粒材料在低冷速相变过程中出现了片状珠光体,最低硬度为305HV,贝氏体转变对应冷速区间较小;大晶粒材料在各冷却条件下无珠光体产生,且贝氏体转变区较大,最低硬度为423HV。150μm和20μm晶粒材料的贝氏体相变激活能分别为124kJ·mol^(-1)和134kJ·mol^(-1)。
Continuous cooling transformation（CCT）curves of SDP1 with 150μm and 20μm grain size were tested by dilatometer.Based on the curves,the effect of grain size on phase transformation,microstructure and hardness of the SDP1 steel were studied by means of OM,SEM,hardness test,thermodynamic calculation and kinetic analysis.The experimental results showed that specimen with smaller grain could display lamellar pearlite in the low cooling rate conditions with hardness about 305 HV and had a smaller bainitic transformation zone.The specimen with bigger grain size had no pearlite formation and bainitic transformation zone was larger with hardness about 423 HV.The activation energy of bainitic transformation of specimens with grain size of 150μm and20μm were 124kJ·mol^-1 and 134kJ·mol-1,respectively.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2017年第6期86-92,共7页
Materials Reports
基金
国家科技支撑计划课题(2007BAE51B04)
关键词
预硬型塑料模具钢
晶粒尺寸
相变
贝氏体
CCT曲线
pre-hardening plastic mould steel
grain size
phase transformation
bainite
CCT diagrams
