BUILD-UP WELDING METHOD THAT OMITS POST-WELDING HEAT TREATMENT

PURPOSE:To simplify operating stages and to eliminate the need for post heat treatments at high temps. by preheating high strength low and middle alloy steel to the temp. just above its Ms point, and build-up welding mild steel thereon then applying temper beads without using any filler metal. CONSTITUTION:High strength steel base materials which are materials to be welded are preheated to the temp. just above the Ms point thereof and are held at this temp. The root pass of mild steel is build-up welded to this material by a TIG welding method. While this is held at the preheating temp. after this, temper beads without filler metal are applied thereon by a TIG welding method, and these are cooled as they are down to a room temp., or they are held at the temp. just above the Ms point for a required time in succession, after which they are cooled down to a room temp. The hardness of the heat effected zone of the high strength steel is maintained in a normal state by said treatment.