Third generation high strength low alloy steels with improved toughness  

作　　者：SUN XinJun LI ZhaoDong YONG QiLong YANG ZhiGang DONG Han WENG YuQing 

机构地区：[1]Institute for Structural Materials,Central Iron and Steel Research Institute,Beijing 100081,China [2]Department of Materials Science and Engineering,Tsinghua University,Beijing 100084,China [3]Chinese Society for Metals,Beijing 100711,China

出　　处：《Science China(Technological Sciences)》2012年第7期1797-1805,共9页中国科学（技术科学英文版）

基　　金：supported by the National Basic Research Program of China ("973" Program) (Grant No. 2010CB630805);the National Natural Science Foundation of China (Grant No. 51071089)

摘　　要：On-line thermo mechanical controlled processing(TMCP) was conducted to develop the third generation high strength low alloy(HSLA) steel with high toughness economically.The ultra-low carbon content ensured a high level of upper shelf energy while ultrafine lath martensitic structure transformed from super-thin pancaked austenite during controlled rolling and cooling.The reduction of martensite block size decreased ductile-to-brittle transition temperature(DBTT) and compensated the strength loss due to carbon reduction.Consequently,the excellent balance of strength and toughness values was obtained as 950-1060 MPa for yield strength,180 J for Charpy V-notch impact absorbed energy at 30℃,which is much superior to that of traditional martensitic steel.Two mechanisms for the refinement of lath martensite block were proposed:One is the austenite grain refinement in the direction of thickness,and the other is the reduction in the fraction of sub-block boundaries with small misorientation and the increase in the fraction of block boundaries with large misorientation,possibly due to austenite hardening.

关 键 词：pancaked austenite lath martensite PRECIPITATE TMCP HSLA steel 

分 类 号：TG142.33[一般工业技术—材料科学与工程] TQ325.14[金属学及工艺—金属材料]