【摘要】 采用焊接热模拟技术制备了低合金高强钢双道次激光电弧复合焊热影响区的均匀化组织试样，研究了二次峰值温度对热模拟试样微观组织和韧性的影响.结果表明，未转变粗晶区为粗大的板条马氏体，晶粒尺寸在84～98μm之间.超临界再热粗晶区为细小的板条马氏体，晶粒尺寸为15.7～19.2μm.临界再热粗晶区为晶界和亚晶界分布有块状M-A组元的板条马氏体.亚临界再热粗晶区组织为板条马氏体，晶粒尺寸在79～88μm之间.示波冲击试验结果表明，临界再热粗晶区试样抵抗裂纹形成能力最低，临界再热粗晶区和未转变粗晶区试样抵抗裂纹扩展能力最差.更多还原

【Abstract】 Homogeneous specimens of the double-pass laserarc hybrid welding heat affected zone(HAZ) of low alloy high strength steels were prepared by welding simulation technology, the influence of second peak temperature on the microstructure and toughness of the simulated specimens was investigated. The results showed that the unaltered coarse grained HAZ(UACGHAZ) compose of coarse lath martensite(LM)with an average grain size between 84-98 μm. The supercritically reheated CGHAZ(SCRCGHAZ) is comprised of fine LM with an average grain size between 15.7-19.2 μm. The intercritically reheated CGHAZ(ICCGHAZ) compose of LM with blocky martensite-austenite constituents distributed along grain boundaries and subgrain boundaries. The subcritically reheated CGHAZ(SRCGHAZ) is comprised of LM with an average grain size between 79-88 μm. The instrumented impact test results showed that the ICCGHAZ specimens own the lowest resistance to crack initiation, and the ICCGHAZ and UACGHAZ had the poorest resistance to crack propagation.更多还原