轧后超快速冷却终冷温度对780 MPa级建筑用钢屈强比的影响  

Effect of Final Temperature of Ultra Fast Cooling after Rolling on Yield Ratio of 780 MPa Constructional Steel

作　　者：康健[1] 王昭东[1] 袁国[1] 王国栋[1] 

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110004

出　　处：《机械工程材料》2011年第11期1-4,共4页Materials For Mechanical Engineering

基　　金：中央高校基本科研业务费资助项目(N090607001);国家科技支撑计划项目(2006BAE03A08)

摘　　要：利用实验室φ450 mm二辊可逆式热轧机及超快速冷却设备研究了轧后超快速冷却终冷温度对780 MPa级高强度低屈强比建筑用钢显微组织及屈强比的影响。结果表明:随着轧后终冷温度由630℃降低至360℃,试验钢的强度和屈强比均呈上升趋势,显微组织则由以贝氏体铁素体为软相基体、M/A岛为硬质弥散第二相的复相组织向板条贝氏体占主体的单一组织转变,其屈强比由0.69升至0.94;当终冷温度为550℃左右时,其屈服强度和抗拉强度分别为650 MPa和955 MPa,屈强比为0.68,伸长率达到19.2%。The effect of final temperature of ultra fast cooling after rolling on microstructure and yield ratio was studied in laboratory by a Ф 450 mm hot-rolling mill and an ultra fast cooling system. The results show that the strength and yield ratio of the tested steel increased when final cooling temperature varies from 630 ℃ to 360℃, and microstructure passed through the transformation of composite phases microstructure including bainite ferrite matrix and M/A island phase to the single lath bainite microstructure, and the yield ratio increased to 0. 94 from 0. 69. When final cooling temperature was about 550 ℃, the yield strength was 650 MPa, the tensile strength was 955 MPa, the yield ratio was 0. 68, and the elongation was about 19. 2%.

关 键 词：建筑用钢 屈强比 超快速冷却 终冷温度 M/A岛 

分 类 号：TG146.1[一般工业技术—材料科学与工程]