Abstract: A three-dimentional analytical model for heat conduction in a plate of finite size with a Gaussian distributed moving heat source, is obtained using the cumulation principle and the mirror method in are welding, and a estimated method of back face penetration is introduced making use of the model and the measured top face information of temperature field. To prove the validity of the model, a series of GTA bead-on-plate welding are performed on a medium carbon steel under various welding conditions, the experimental results show that this control model can provide acceptable accuracy, so the next penetration control will be based on the model.

Key words: Analytical model, Penetration control, Temperature field