焊接材料及热输入对Q460钢厚板焊接接头拉伸性能的影响

Effect of Welding Material and Heat Input on Tensile Property of Welded Joint of Q460 Steel Thick Plate

在不同热输入(12.6,16.4,19.5kJ·cm^(-1))下分别对Q460低合金高强钢厚板进行实心焊丝和药芯焊丝CO2气体保护焊,研究了焊丝和热输入对接头显微组织及拉伸性能的影响。结果表明:随热输入增加,2种接头焊缝中柱状晶区的针状铁素体比例降低,大尺寸晶界铁素体增多;实心焊丝焊接接头焊缝区的硬度随热输入增加变化不大,药芯焊丝焊接接头的显著降低;实心焊丝焊接接头的屈服强度和抗拉强度与母材的相当,断后伸长率明显小于母材的,且断后伸长率随热输入的增加而降低;药芯焊丝焊接接头在低热输入下的强度与母材的相当,热输入的增加使抗拉强度损失显著,但对屈服强度和断后伸长率影响很小。

Low-alloy high-strength steel Q460thick plates were welded by CO2gas shielded arc welding with solid wire and flux-cored wire at different heat inputs(12.6,16.4,19.5kJ·cm-1).The effects of welding wire and heat input on the microstructure and tensile properties of the joint were investigated.The results show that the proportion of acicular ferrite in columnar grain zone in weld zone of the two joints decreased and the grain boundary ferrite of large size increased with the increase of heat input.The hardness of weld zone of the joint welded with solid wire changed little with the increase of heat input,but that of the joint welded with flux-cored wire decreased significantly.The yield strength and ultimate tensile strength of the joint welded with solid wire were similar to those of base metal whereas the elongation was lower than that of base metal;the elongation decreased with the increase of heat input.The strenth of the joint welded with flux-cored wire was equivalent to that of the base metal at lower heat input.The increase of heat input obviously reduced the tensile strength,but affected the yield strength and elongation slightly.