Weld Mold 958 description: For repairs, prepare area to be welded by removing all cracks, heat checks or other defects. Preheat die blocks and other units where the entire working surface is to be welded to 800F. On other alloys preheat and post-heat according to the base metal. Maintain temperature during welding. Use the stringer bead technique to minimize heat input. Peen the weld when red hot to relieve stresses. After welding, cool in still air to 300F. to obtain the ultimate grain refinement and uniform hardness in the weld deposit. Temper at 1000F. for one hour per inch of thickness. Cool in still air to room temperature.