摘要
采用三种热输入进行1000MPa级控轧控冷(Thermo mechanical control process,TMCP)高强钢的熔化极气体保护焊,利用金相显微镜、扫描电子显微镜和透射电子显微镜研究热输入对焊接接头组织和力学性能的影响。研究结果表明,三种热输入焊缝金属组织主要由板条马氏体和板条贝氏体为主、并含有少量残余奥氏体和粒状贝氏体;焊接热影响区粗晶区组织以板条马氏体和贝氏体为主,并含有少量粒状贝氏体。随着热输入的增加,焊缝组织中贝氏体板条粗化,马氏体板条减少,而粒状贝氏体逐渐增多,部分膜状残余奥氏体向块状转变;焊缝金属冲击韧度和硬度、接头强度逐渐降低,而接头热影响区冲击韧度先增后降;当热输入为15k J/cm时焊接接头强韧性匹配最佳。
1000MPa high-strengthsteelplate（thermo mechanical control process（TMCP） steel） for construction machinery is welded by metal active gas（MAG） welding method with GHS90 welding wire as filler material under three heat inputs, and effects of heat input on microstructure and properties of the weld joint are investigated by means of optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that the microstructure of weld metal consist prodominantly of lath martensite and lath bainite, a small amount of granular bainite and a few retained austenite for three kinds of heat input. The microstructure of the coarse grained heat affected zone（CGHAZ） consists of lath martensite, lath bainite, a small amount of granular bainite. When the heat input is increased, the lath of martensite and bainite is coarsened, the amount of martensite decreases graduslly, while the munber of granular bainite increases, and topographies of retained austenite is changed from thin film to block. With the increased of heat input, the low temperature impact toughness and the hardness of weld metal is reduced gradually, but the impact toughness of heat affect zone initially increases and then decreases. Whenthe heatinput is15 k J/cm, the welded joints with the combination of high strength and good toughness could be achieved.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第22期42-49,共8页
Journal of Mechanical Engineering
基金
国家重点基础研究发展计划资助项目(973计划
2010CB630805)
