A Study of the Microstructure and Properties of Dual-Phase Steels Processed Using A Continuous Galva

• 作 者: Yu Gong Anthony J. DeArdo
• 机 构: Basic Metals Processing Research Institute Mechanical Engineering and Materials Science University o
• 出 处: 第十届中国钢铁年会暨第六届宝钢学术年会
• 发表日期: 2015年11期
• 关键词: galvanizing high strength dual phase steels vanadium addition hole expansion hig

　　This paper reports recent research into methods of improving the strength and formability of high strength Dual-Phase steels after processing using continuous galvanizing line(CGL)simulations.In this study changes in both composition and processing were explored.The base composition was a low carbon C-Mn-Si steel which would exhibit good spot weldability.To this steel were added two levels of Cr and Mo for strengthening the ferrite and increasing the hardenability of the intercritically formed austenite.Also,these steels were produced with and without the addition of vanadium in an effort to further increase the strength.Since earlier studies revealed a relationship between the nature of the starting cold rolled microstructure and the response to CGL processing,the variables of hot band coiling temperature and level of cold reduction prior to annealing were also studied.Finally,in an effort to increase strength and ductility of both the final sheet(general formability)and the sheared edges of cold punched holes(local formability),a new thermal path was developed that replaced the conventional GI ferrite-martensite microstructure with a new ferrite-martensite-tempered martensite and retained austenite microstructure.The new microstructure exhibited a somewhat lower strength but much high general and local formabilities.In this paper,both the physical and mechanical metallurgy of these steels and processes will be discussed.This research has shown that simple compositions and processes can result in DP steels with so-called Generation III properties.