Innovative Hybrid High-Pressure Die-Casting Process for Load-Bearing Body-In-White Structural Components

This paper introduces an innovative manufacturing process for hybrid components in the automotive body-in-white (BIW) structure, made of high-strength steel BR1500HS and the aluminum cast alloy AlSi10MnMg. The casting method is high-pressure die casting (HPDC), known for producing components with intricate shapes in light alloys. The combination of Design of Experiments (DoE) and simulation is employed to assess and optimize input process parameters effectively. The simulation, conducted using a commercial simulation software, ProCAST and Abaqus, visualizes the casting operation and the heat transfer between the two dissimilar materials. The primary focus is on investigating the shrinkage porosity defect under various HPDC process conditions. The simulation and experimental results indicate that the melting temperature of the aluminum alloy has the most significant impact on shrinkage porosity, followed by injection velocity and injection pressure, whereas mold/tube initial temperature has a lesser effect. Optimal process parameters are identified as a melting temperature of 700 degrees C, a first-stage velocity of 0.4 mm/s for 0.4 s, a second-stage velocity of 2.5 mm/s for 0.3 s, and a mold/tube initial temperature of 150 degrees C. Furthermore, the study explores another challenging defect, which is the steel tube deformation under high casting pressure. An effective solution is proposed and tested by using internal air pressure support for the tube. Results demonstrate a notable improvement in final product quality, wall thickness uniformity, and a reduction in steel tube deformation magnitude to 1.9 mm compared to 6.26 mm in the case of hybrid-HPDC without air pressure support.