| H13 is a popular 'hot work' tool steel that is used extensively for die casting dies and inserts. These dies fail over a period of time by gross cracking, thermal fatigue failure, wear or erosion and chemical attack. In particular, failure by thermal fatigue is a prominent mode of failure that results in the formation of numerous 'heat checks' or micro-scale cracks that prevent the use of the die beyond a certain point.;Laser welding was found to be a viable option for repair welding H13 tool steel. Instrumented impact test results demonstrated an impact strength of 20-30% of as-machined steel. Undissolved carbides were round to be a prominent feature of the microstructure and fatigue crack growth tests indicated a reduction in life post welding. A preliminary cost analysis indicated that a die life recovery greater than 9% post welding would make laser assisted repair welding attractive.;A laser assisted welding technique has been used to repair failures that are representative of the cracks formed on die casting dies. Welding parameters and conditions were optimized to prevent longitudinal center fine cracking. The processed region was characterized for hardness, microstructure, composition and mechanical properties. |
