大热输入焊接EH36船板钢接头力学性能

以EH36高强度船板钢为研究对象,通过拉伸和冲击分析试验手段,对EH36船板钢不同热输入埋弧焊接头进行了力学性能测试,同时采用扫描电镜对冲击试样断口形貌进行分析.结果表明,所有断裂均发生在拉伸试样的母材区,EH36船板钢在大焊接热输入条件下,焊缝和焊接热影响区的强度好于母材,并没有出现热影响区软化现象;随着焊接热输入增加焊缝的冲击韧性降低,从焊缝和熔合区断口形貌来看,断裂类型为韧性断裂和准解理断裂的混合断裂.随着远离熔合线距离的增加,冲击吸收功有增加的趋势,在距离熔合线4 mm处的冲击吸收功跟母材接近,说明该位置处韧性基本不受焊接热循环的影响.

Effects on mechanical properties of high welding heat-input for EH36 shipbuilding steel joint

Based on the EH36 high-strength ship plate steel,the effects of welding heat input on mechanical properties by tensile and impact test in submerged arc welding process were investigated in the paper.The microscopy-shaped of fracture was also analyzed by scanning electron microscope(SEM).The results showed that all the fracture occurred in base metal.In the large heat input welding condintions,the strength of joints and heat affected zone(HAZ) was better than that of the base metal and no softening phenomenon in HAZ.The impact toughness of joint decreased as the welding input increased.The fracture morphology of weld and fusion zone was the mixed fracture for toughness and quasi-cleavage fracture.With the distance from the fusion line increased,the impact value tended to increase.The impact value was close to the value of base material at distance of 4 mm away from the fusion line which indicated the toughness of this position was not affacted by welding heat cycle.