This work aims to present a method to establish arc welding procedures on steels for molds and dies. The welding of AISI P20 steel was studied. Simple and multi-pass welding were undertaken using the Tungsten inert gas process, evaluating the bead geometry, hardness distribution, microstructure and quality features after grinding, polishing and texturing. By the bead implant test and analytical heat transfer solutions, multi-pass welding techniques were optimized to cause the tempering effect to the weld metal and heat affected zone by a second thermal cycle of welding. In the welding of P20 steel it is necessary to apply the double layer and temper bead techniques. The temper bead demands refined techniques to control the welding variables.