回火温度对500 MPa级海工钢组织性能的影响  

Effect of tempering temperature on microstructure and properties of 500 MPa grade offshore engineering steel

作　　者：麻亚鑫 贾潇 杨宇龙 王丙兴[1] MA Yaxin;JIA Xiao;YANG Yulong;WANG Bingxing(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,Liaoning,China;Key Laboratory of Electromagnetic Processing of Materials,Ministry of Education,NortheasternUniversity,Shenyang 110819,Liaoning,China)

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,辽宁沈阳110819 [2]东北大学材料电磁过程研究教育部重点实验室,辽宁沈阳110819

出　　处：《钢铁研究学报》2022年第12期1465-1475,共11页Journal of Iron and Steel Research

基　　金：中央高校基本科研专项资金资助项目(N2007009)。

摘　　要：为了研究500 MPa级海洋工程用钢板组织性能的调控工艺,采用离线淬火+回火(RQ-T)工艺研究了回火温度对实验钢的组织及力学性能的影响。结果表明:实验钢经920℃淬火+450℃回火处理,显微组织主要为回火马氏体,随着回火温度升高至650℃,碳化物逐渐聚集并球化。强度指标随着回火温度升高逐渐下降,而伸长率、低温冲击功逐渐升高。在920℃淬火+650℃回火时,平均屈服强度为550 MPa,-20℃低温冲击功平均值为261 J。随着回火温度的升高,位错密度逐渐下降,大角度晶界所占比例升高,有效阻碍裂纹扩展。M-A岛含量有所减少并伴有大量粒状碳化物析出并球化,呈弥散分布基体上。In order to study the controlling technology of the microstructure and property of 500 MPa grade ocean engineering steel plate, off-line quenching + tempering(RQ-T) process was used to study the effect of tempering temperature on the microstructure and mechanical properties. The results show that after quenching at 920 ℃ and tempering at 450 ℃, the microstructure is mainly tempered martensite, and with the increase of tempering temperature to 650 ℃, carbides gradually aggregate and spheroidize. The tensile and yield strengths decrease gradually with the increase of tempering temperature, while the elongation and low-temperature impact toughness increase gradually. When quenched at 920 ℃ + tempered at 650 ℃, the yield strength reaches 551 MPa and the low-temperature impact energy at-20 ℃ reaches 261 J, which show excellent comprehensive mechanical properties. With the increase of tempering temperature, the dislocation density gradually decreases. The proportion of high-angle grain boundaries gradually increases, which effectively hinder the crack propagation. The content of M-A islands in the microstructure decreases and disappears gradually, and a large number of granular carbides precipitate and spheroidize, dispersing in the matrix.

关 键 词：海洋工程用钢 回火温度 M-A岛 低温冲击韧性 

分 类 号：TG156.5[金属学及工艺—热处理]