NARROW GAP MIG ARC WELDING METHOD

摘要

PURPOSE:To obtain a good welding metal by performing a narrow gap MIG arc welding in the gas shielding atmosphere containing the specific quantity of CO2, O2 in the inert gas with He as the essential component. CONSTITUTION:The composition of the shielding gas is Ar+He+CO2 or Ar+He+O2 containing 2-10% CO2 and 0.7-3.3% O2. It is necessary to contain at least 25-2.5X[CO2%] He gas in the shielding gas as well. This is because of preventing the creeping up of arc at the narrow gap MIG welding time of 10.0mm gap width due to DC reversed polarity and when He is added exceeding the upper limit a spatter is caused. In case of mixing O2 as the activated gas the H2 gas of 25-7.5X[O2%] is added. By performing the narrow gap MIG are welding like this the creeping-up of the arc in the conventional welding wire is prevented and also the weld metal having excellent tenacity is obtd. with controlling the oxygen in the welded metal.