直流正接在双丝埋弧焊中的应用

在采用多丝埋弧焊工艺焊接小直径、薄壁厚的钢管时，由于钢管壁厚小，易造成内焊烧穿，为避免烧穿而减小焊接参数时又会带来焊缝内部气孔、夹渣等缺陷，通过改变焊接电源极性的方法，即两丝埋弧焊内焊的第一丝采用直流正接的方法来解决此问题。选择壁厚为10.3 mm规格钢管进行试验，内焊第一丝（前丝）电源极性采用直流正接，二丝（后丝）采用交流的焊接工艺，焊缝质量良好，且各项力学性能指标均满足标准要求。

Application of DCSP in Double Wires Submerged Arc Welding

During the welding small-diameter and thin-thickness pipe with multi-wires submerged arc welding technology, due to the thinner thickness of the pipes, it is easy to cause inner welding burn through. In order to avoid burn through, it can reduce welding parameters; however which can bring other defects such as the gas pocket in weld, slag inclusions and others. In view of this situation, it can solve such problems through changing the welding source polarity, that is adopting DCSP to the front wire during double wires submerged arc welding. Selecting the pipe with 10.3 mm thickness to conduct test, DCSP is adopted for source polarity of inner welding front wire, and AC for the back wire. The weld quality is perfect, and all the mechanical properties can meet the requirements of standard.