A computational fluid dynamic analysis of the effect of weld nozzle geometry changes on shielding gas coverage during gas metal arc welding

摘要

Three geometry changes to the inner bore of a welding nozzle and their effects on weld quality during gas metal arc welding (GMAW) were investigated through the use of computational fluid dynamic (CFD) models and experimental trials. It was shown that an increased shielding gas exit velocity increased the gas column’s stability and therefore its resistance to side draughts. Double helix geometry within the nozzle reduced the gas column’s stability by generating a fast moving wall of gas around a slow moving centre. A pierced internal plate initially increased the gas velocity, however, the nozzle was unable to maintain the velocity and the change produced gas columns of similar stability to a standard nozzle. A pierced end plate produced the best results, increasing the shielding gases exit velocity sufficiently to marginally outperform the standard 16 mm welding nozzle.