X70钢板冷填丝气体保护焊工艺研究

为了改善高钢级管线钢焊缝及热影响区的低温冲击韧性，采用焊接工艺参数完全相同的常规MAG焊和冷填丝MAG焊接方法，对X70钢级管线钢进行了焊接对比试验，并对焊接接头进行了低温夏比冲击试验、拉伸试验和金相试验。试验结果显示，在焊接电流相同条件下，冷填丝MAG焊可提高焊丝熔化量30%~55%；在0 ℃、-10 ℃、-20 ℃、-30 ℃时，冷填丝MAG焊接工艺相对于常规MAG焊接工艺，焊缝冲击值有升有降，但热影响区冲击值均有不同程度的提高。研究表明，冷填丝MAG焊接工艺对焊缝及热影响区具有加速冷却作用，尤其有利于改善热影响区的低温冲击韧性，适用于耐磨及耐腐蚀金属表面堆焊，以及对熔深要求较低的中厚板的低线能量、高效多层多道焊接。

Experimental Study on Gas Shielded Welding of X70 Steel Plate with Cold Filler Wire

In order to improve the low-temperature impact toughness of the high-grade pipeline steel weld and the heat affected zone, the conventional MAG welding and the cold filled wire MAG welding methods with the identical welding process parameters were used to carry out the welding contrast test of X70 steel pipeline steel, and the low-temperature Charpy impact test, tensile test and metallographic test of the welded joint were carried out. The results show that under the same welding current, the melting rate of the welding wire can be increased by 30%~55%. At 0 ℃, - 10 ℃, - 20 ℃ and - 30 ℃, compared with the conventional MAG welding process, the impact value of the cold filled wire MAG weld increased and decreased , but the impact value of the heat affected zone increased in different degrees. The results show that the cold filled wire MAG process can accelerate the cooling of the weld and HAZ, especially improve the low temperature impact toughness of HAZ. It is suitable for surfacing of the wear-resistant and corrosion-resistant metal surface, and low line energy, high efficiency, multi-layer and multi pass welding of the medium and thick plates requiring low penetration.