Numerical analysis of keyhole establishment time in keyhole plasma arc welding

Numerical analysis of keyhole shape and keyhole establishment time is of great significance for selection and optimization of the process parameters in keyhole plasma arc welding.In this paper,a three-dimensional transient model is developed to analyze the evolutions of keyhole shape and keyhole establishment time in continuous current plasma arc welding process.Firstly,a combined volumetric heat source model is used to simulate the transient variation of temperature field.And then the surface deformation equation is adopted to calculate dynamic features of the keyhole shape and keyhole establishment time inside weld pool,in which the force action on weld pool surface is considered.Experiment is conducted to validate the numerical simulation results.The predicted keyhole size and keyhole establishment time are in agreement with the experimental measurement.And the calculated fusion zone geometry is consistent with the measured one.