High Temperature Plastic Deformation Behavior and Brittle Mechanism of S450EW Steel  

作　　者：CHEN Jiping HU Xuewen QIAN Jianqing 陈继平;HU Xuewen;QIAN Jianqing(School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243032,China;Technology Center of Masteel,Maanshan 243000,China)

机构地区：[1]School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243032,China [2]Technology Center of Masteel,Maanshan 243000,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2022年第4期722-729,共8页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the National Natural Science Foundation of China(No.51774006)。

摘　　要：High-temperature tensile tests were conducted for high corrosion resistant weathering steel S450EW.The morphologies of fracture microstructures,dislocations and precipitates were investigated by field emission scanning electron microscopy and transmission electron microscopy.The high-temperature plastic deformation behavior and brittle mechanism of S450EW steel were also studied.The experimental results show that the ductility troughs appear at 700-850℃ and 650-900℃ when the strain rates are 3×10^(-3)and 1.5×10^(-2)s^(-1),respectively.With the increase of strain rates,the ductility trough moves to the lower temperature side.The hot ductility is best when the cooling rate is 5℃/s before deformation at 750℃and the area reduction rate reaches 60.56%.Fine second phase particles and inclusions precipitated before and during deformation provide effective core positions for microcracks or microvoids formation during deformation process.It is also easy to cause stress concentration which results in microcracks or microvoids between grains during deformation and ultimately causes damage along the grain boundaries.The precipitated particles inhibit austenite dynamic recrystallization and therefore enhance intergranular fracture along austenite grain boundaries.The deformation induced proeutectoid ferrite films distribute along the austenite grain boundaries hinder the dynamic recrystallization.The deformation concentrated on network ferrite films produces damage of grain boundaries.

关 键 词：corrosion resistant steel hot ductility dynamic recrystallization DIFT brittle mechanism 

分 类 号：TG142.1[一般工业技术—材料科学与工程]