بررسي تاثير پارامترهاي جوشكاري روي عمر خستگي حرارتي قالبهاي ريخته گري تحت فشار

Study of the effects of welding parameters on thermal fatigue life of die casting molds

HI3 steels with a good thermal resistance at high temperatures are widely used as materials for permanent molds in non-ferrous alloy castings such as magnesium, aluminum and copper alloys. The surfaces of the said molds are rapidly damaged by corrosion, erosion and thermal fatigue during casting. These damages are repaired normally by means of welding with Tungsten electrodes (TIG) and mar-aged steel fillers. However, the resulted mechanical properties of the welded sections are normally weak and thermal fatigue cracks are appeared rapidly in service conditions. Refinement of dendrite size in the welded sections is often possible by modifying the welding process. In this study the effect of welding current on macrostructure and thermal fatigue life of welded H13 sections are studied.