Effects of Process Parameters on Joint Formation and Mechanical Performance of Self-Piercing Riveted Dissimilar Joints between B1500HS Steel and AZ31B Magnesium Alloy

This study investigates the feasibility of self-piercing riveting (SPR) for joining dissimilar materials, specifically B1500HS ultra-high-strength steel and AZ31B magnesium alloy. SPR joints were fabricated under different process parameters, and their cross-sectional morphology and static mechanical performance were systematically characterized. Joint morphology and static strength were investigated experimentally in relation to die geometry, rivet height, and sheet stacking sequence. The findings demonstrate that joint performance is primarily determined by the sheet stacking sequence. When the B1500HS is placed as the upper sheet, the rivet penetration improves and the rivet shank expands more effectively, resulting in enhanced mechanical interlocking. Within the investigated parameter range, the combination of Die 433, a rivet height of 6.0 mm, and ultra-high-strength steel as the upper sheet produced a stable interlocking structure with an average static joint strength of 6.18 kN. This study establishes a viable process window for SPR joining of B1500HS-AZ31B dissimilar materials and provides experimental evidence and practical guidance for process selection in lightweight structural applications.