带极堆焊中的电弧磁控技术研究进展

带极堆焊包括埋弧焊和电渣焊两种焊接形式,已为广泛应用于改善设备的的耐腐蚀、耐磨蚀性能。为了提高生产效率,往往需要采用较大的焊接电流或较宽的带极。然而,这极易导致电弧偏吹、熔深加大及焊道成形不良等缺陷。国内外对带极堆焊中磁控技术的研究发现,利用外加磁场可以有效地减小熔深、改善焊道成形。分别对带极埋弧堆焊和电渣堆焊两种情况下外磁场对焊接质量的不同影响进行了讨论。并指出,带极埋弧堆焊时施加振荡磁场,通过电磁搅拌作用可以有效地减小焊缝金属的稀释率及腐蚀速率,并且这种磁控电弧在保证一定稀释率的前提下允许采用更大的焊接电流,以提高生产效率,且不影响焊接质量。在带极电渣堆焊时,则可利用外加磁场来改变熔池上的磁场分布和熔渣、熔池金属的流向,从而有效地抑制了堆焊中的咬边及焊道成形缺陷。

Research on Magnetic Steering of Arc in Strip Cladding

Strip cladding, including two kinds of processes such as submerged arc welding(SAW) and electro slag welding(ESW), was often used to improve the corrosion and attrition resistance of some equipments. The productivity of this process has been increased usually by the use of higher welding currents and wider strips. But the associated problems are arc-blow, increasing the penetration and poor bead characteristics. The researches abroad and home on magnetic steering in strip cladding indicated that magnetic steering can reduce the penetration and improves the bead shape. The different effects of added magnetic field on the welding quality in SAW and ESW were analyzed in this paper. When adopting submerged arc strip cladding, oscillating magnetic field used to steering the arc can reduce the dilution and corrosion rate. Meanwhile it permits to use higher current for a given dilution level, thus increasing productivity without affecting the bead shape. While electro slag strip welding, the auxiliary magnetic field can change the force acting on a weld pool and the flowing direction of the molten metal and molten slag so as to retard the undercut and defective shape of bead.