690MPa级海洋平台用钢的组织和性能  

Microstructure and properties of 690MPa grade off-shore platform plate steel

作　　者：吴辉[1] 赵燕青[1] 李闯[1] 王学敏[1] 

机构地区：[1]北京科技大学材料物理与化学系,北京100083

出　　处：《金属热处理》2010年第9期20-25,共6页Heat Treatment of Metals

基　　金：国家"863"计划(2008AA03Z501)

摘　　要：根据测出的CCT曲线制定了690 MPa级海洋平台用钢的轧制工艺,研究了试验钢低碳贝氏体钢回火前后组织对性能的影响。研究了Cu在650℃的时效行为及其时效硬化规律。结果表明,650℃回火1 h后试验钢的屈服强度达到780 MPa以上,伸长率达到18.5%,-60℃冲击功达到81 J;由于ε-Cu的析出在45 min时效时出现硬度峰,大量Cu相在位错线、板条界及铁素体内析出,尺寸在40~50 nm,有强烈沉淀强化作用,随着时效时间的延长,沉淀强化作用减弱。The rolling parameter of 690 MPa grade off-shore platform plate steel was optimized through CCT curves,and the effect of microstructure on mechanical properties before and after tempering was studied in low carbon bainitic steel;Cu precipitation behavior in a Cu-bearing steel was investigated at 650 ℃ when aging.The experimental results indicated that the yield strength exceeded 780 MPa,elongation was up to 18.5% and the toughness value at-60 ℃ reached 81 J;hardness-peak was appeared when aged after 45 min,and fine Cu particles precipitated largely along dislocation line,lath boundaries and in ferrite with the size 40-50 nm,which contributed to strong precipitation strengthening,and finally the effect of strengthening was weakened.

关 键 词：低碳贝氏体钢 CCT曲线 时效处理 回火 ε-Cu析出 

分 类 号：TG151.2[金属学及工艺—热处理] TG113[金属学及工艺—金属学]