热输入对BWELDY960Q钢焊接接头组织性能的影响

采用MAG焊方法焊接低合金高强度钢BWELDY960Q,在不同焊接工艺参数下获得焊接接头,研究焊接热输入对焊接接头组织性能的影响. 结果表明,随着焊接热输入的提高,焊缝中针状铁素体的体积分数呈现先增加后减少的趋势,当焊接热输入为12.32 kJ/cm时,焊缝中获得的针状铁素体所占的比例达到最大值. 针状铁素体数量的增加,提高了焊缝和熔合区的冲击吸收功、焊接接头的抗拉强度、断后伸长率和断面收缩率. 焊缝冲击断口呈韧窝花样,等轴韧窝与抛物线韧窝交替分布. 熔合区冲击断口呈解理特征,解理台阶层次明显,并存在较多的撕裂棱.

Effect of heat input on microstructure and properties of welded joint of BWELDY960Q steel

In this paper, high strength low alloy BWELDY960Q steel was welded by using MAG, microstructure and properties of welded joint at different welding specification parameters were studied. The results show that the volume percentage of acicular ferrite in weld metal obviously appears declined tendency after going up with the heat input increase, which reaches maximum at the heat input of 12.32 kJ/cm. The impact toughness of weld metal and fusion zone, tensile strength, elongation rate and shrinkage of welded join are improved due to the quantity change of acicular ferrite in weld metal. Impact fracture of weld metal is character of dimple, equiaxed and parabolic dimples alternatively distribute on section. However, there are many obvious tearing ride and cleavage steps in impact fracture of fusion zone.