Gas Flow Observation During VPPA Welding Using a Shadowgraph Technique

摘要

The importance of protecting liquid metal from atmosphere during fusion welding is well known. The mechanical properties of a weld can be dramatically diminished if the liquid metal is not well protected. One way of protecting the weld pool is to use a continuous stream of inert or reducing gas which surrounds the weld pool as it forms. The observation of this shielding gas flow is useful in understanding its performance during welding. In particular, turbulence in the shield gas flow may permit entrainment of atmosphere into the protected region of the weld. It is anticipated that a better design of the shield gas nozzle will result from such observations.