Assessing Mechanical Performance of Dissimilar Steel Systems Made Via Wire-Arc Additive Manufacturing

Hot stamping is part of a specific type of metalworking procedure widely used in the automotive industry. This research seeks to help make hot stamp tooling component production more cost-effective by using large-scale additive manufacturing. Additive manufacturing can produce dissimilar steel components that can be more cost-effective and time-efficient and allow for complex geometries to be made. A dissimilar steel system consisting of 410 martensitic stainless steel and AWS ER70S-6 mild steel is proposed to make hot stamps, making them more cost-efficient. However, the material interface's mechanical behavior in 410SS-mild steel additively manufactured material systems is not well understood. This research seeks to find how these dissimilar hot stamps can potentially fail during service. To assess the mechanical behavior of the material interface, mechanical testing by way of hardness testing, thermal expansion testing, fatigue testing, and microscopic imaging were performed. Samples were heat-treated, and fatigue tests were designed to run for 1200 cycles at a temperature range of 200-600$^{\circ}$C. Fatigue test results show that, as expected, all four samples went through plastic deformation, with hardness test results used to confirm this behavior. Microscopy was done to show the post-test microstructure that shows potential evidence of plastic deformation sites. One of the materials in the dissimilar system did not meet the hardness requirements for hot stamping applications, but recommendations are made to address this.