船用高强钢大线能量焊接接头组织性能研究

Study on Microstructure and Properties of Large Line Energy Input Welded Joints of High-Strength Marine Steel

采用FCB大线能量焊接方法对30 mm厚EH36船用高强钢板进行焊接试验,研究了焊接接头的显微组织和力学性能。结果表明,线能量为161 kJ/cm时获得的接头成形良好,无气孔、夹杂等缺陷。焊缝组织主要为先共析铁素体与密布的针状铁素体。熔合区存在显著的组织不均匀性,粗晶区主要为片状与块状先共析铁素体,并可见少量黑色珠光体。细晶区主要为细小的白色铁素体与黑色珠光体,呈混杂分布。焊缝硬度值最高,而在热影响区出现了软化区。接头力学性能良好,接头熔合线附近冲击吸收功低于焊缝与母材的,接头抗拉强度均值为545 MPa,断口位置位于热影响区,为典型的韧性断裂。

The welding of 30 mm thick EH36 high-strength marine steel plate was carried out by FCB large energy input welding method.The microstructure and mechanical properties of the welded joint were studied.The results show that the joint obtained when the energy input is 161 kJ/cm forms well,and there are no defects such as porosity and inclusion in the joint.The microstructure of the weld is mainly pro-eutectoid ferrite and dense acicular ferrite.The inhomogeneity of microstructure is significant in the fusion zone.The coarse grain zone is mainly flaky and massive pro-eutectoid ferrite,and a small amount of black pearlite is visible.The fine grain area is mainly composed of fine white ferrite and black pearlite in mixed distribution.The weld has the highest hardness value and a softened zone appears in the heat affected zone.The mechanical properties of the joint are good.The impact absorption energy near the fusion line is lower than that of the weld and the base metal.The tensile strength of the joint is 545 MPa.The fracture location is located in the heat affected zone and the fracture is a typical ductile fracture.