Hot Ductility of 20Cr13 Steel at High Temperature

摘要

Hot ductility of 20Crl3 steel at high temperature was investigated through tensile test. The main phases of the steel in temperature range of 600-1400 ℃ were calculated with thermodynamic software. The fracture morphologies and microstructure were observed by scanning electron microscopy. The steel showed good hot ductility in temperature range of 1000-1200 ℃, and the area reduction was 82 % or more. In temperature range of 800-950 ℃, the M_(23)C_6 precipitated at the grain boundary of austenite, and it fractured in the tensile process. Thus the micro-crack or micro-hole formed at the grain boundary of austenite, and the area reduction was 52-68 %. The ferrite precipitated at 800 or 1250 ℃, and the micro-voids formed at interface of ferrite and austenite because of the discordant deformation of two phases, which was harmful to hot ductility. Moreover, quasi-cleavage fracture happened at 800 ℃ because of the ferrite cleavage, which further decreased hot ductility of the steel.