回火温度对大厚度低碳高强度Q690D钢板组织和力学性能的影响  

Effect of Tempering Temperatures on Microstructure and Mechanical Property of Low-carbon High-strength Heavy Q690D Steel Plate

作　　者：郑建平 ZHENG Jianping(Nanjing Iron and Steel Co.,Ltd.,Nanjing 210035,Jiangsu China)

机构地区：[1]南京钢铁股份有限公司,江苏南京210035

出　　处：《热处理》2020年第3期1-4,共4页Heat Treatment

摘　　要：低碳高强度Q690D钢适用于大型工程的结构件。对含碳量为0.14%~0.16%(质量分数)、厚度为100 mm的Q690D钢板进行了920℃水淬和分别于560℃、580℃及620℃回火处理。分别检测了钢板淬火态及淬火和不同温度回火后的显微组织和力学性能,以研究回火温度对钢板组织和性能的影响。结果表明:①淬火并经3种温度回火的钢板的力学性能均满足标准要求,随着回火温度的提高,强度略有下降,620℃回火的钢板屈服强度为810 MPa,抗拉强度为880 MPa,断后伸长率达16.5%,-20℃纵向冲击吸收能量达137 J;②淬火后钢板从表面到心部的组织均为板条马氏体和少量板条贝氏体,经560℃、580℃、620℃回火后,其组织为回火索氏体加板条贝氏体。综合起来看,大厚度Q690D钢板淬火后的回火温度以620℃最佳。Low-carbon high-strength Q690 D steel is adaptable to components of large-scale engineering.The Q690 D steel plate 100 mm thick,containing 0.14% ~ 0.16% C by mass,was quenched from 920℃ in water and then tempered respectively at 560℃,580℃ and 620℃.Microstructure and mechanical properties of the steel plate after quenching as well as after quenching and tempering at different temperatures were tested.The results showed that ① mechanical properties of the steel plate quenched then tempered at three temperatures all came up to the standard,and the strengths lowered slightly with the increase in tempering temperature,yield strength being810 MPa,tensile strength being 880 MPa,elongation being as large as 16.5%,and longitudinal impact absorption energy at-20℃ being 137 J for the steel plate tempered at 620℃;and ② the microstructures from surface to core of the steel plate consisted of lath martensite and a small amount of lath baitine after quenching,and tempered sorbite and lath bainite after tempering at 560℃,580℃ and 620℃.Taken together,the heavy Q690 D steel plate is best tempered at 620℃ after quenching.

关 键 词：回火温度 大厚度Q690D钢板 显微组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.5[金属学及工艺—金属材料]