热作模具钢SDH3热疲劳机理  

Thermal fatigue mechanism of SDH3 hot work steel

作　　者：佟倩[1] 吴晓春[1] 周青春[1] 闵娜[1] 

机构地区：[1]上海大学材料科学与工程学院,上海200072

出　　处：《材料热处理学报》2010年第5期81-86,共6页Transactions of Materials and Heat Treatment

基　　金：国家科技支撑计划课题(2007BAE51B04);宝山钢铁股份有限公司项目

摘　　要：采用自约束热疲劳试验方法,对比研究了SDH3与H13钢的热疲劳性能,应用扫描电镜研究了SDH3热疲劳过程中裂纹的萌生和扩展,应用透射电镜分析了SDH3钢热疲劳前后显微组织和结构的变化。结果表明:经常规热处理后,SDH3钢热疲劳性能优于H13钢;对SDH3钢来讲,热疲劳裂纹由三叉晶界处萌生,并沿晶界扩展;SDH3钢的马氏体板条间存在薄膜状残留奥氏体,可有效释放裂纹尖端的应力并阻碍裂纹扩展;热疲劳过程中,基体组织发生回复再结晶,碳化物粒子发生粗化。With the self-restricting test method,the thermal fatigue behavior of SDH3 steel and H13 steel was investigated. The formation and propagation of thermal fatigue crack in SDH3 steel was studied by scanning electron microscopy （SEM）. The microstructure of SDH3 steel before and after the fatigue test with thermal cycle from room temperature to 700 ~C was investigated by transmission electron microscopy （TEM）. The results show that SDH3 steel exhibits better thermal fatigue property than that of H13 steel after conventional heat treatments. The initiation of thermal crack in SDH3 steel appears to he associated with triple boundaries and then propagates along grain boundaries. Besides,film-type retained austenite located between lath martensite in SDH3 steel is favorable to relieve the stress at crack tips and retard the crack propagation. After thermal fatigue,recrystallization is observed in the matrix,and carbide coarsening occurs.

关 键 词：热作模具钢 热疲劳机理 微观结构 

分 类 号：TG142.45[一般工业技术—材料科学与工程]