Analysis of competitive failure mechanisms and mechanical properties of self-piercing riveted joints in corrosive environments

In order to study the transition mechanism and mechanical properties of the failure mode of self-piercing riveted joints in corrosive environment, the 0. 6 mol/L NaCl solution was used to carry out the immersion corrosion test on several groups of self-piercing riveted joints. Mechanical properties and failure modes of joints are analyzed by mechanical testing and scanning electron microscopy. The results show that the failure mode of heterogeneous joints changes from Ⅰ to Ⅲ with the prolongation of corrosion cycle, and the transformation rate depends on the joint material, while the failure mode of homogeneous joints is not affected by the corrosion cycle. Under short-term corrosion, the inter-plate corrosion products of self-piercing riveted joints increase the failure load of both homogeneous and heterogeneous joints, the failure load of heterogeneous joints varies widely throughout the corrosion cycle. Heterogeneous joints are less stable, and homogeneous combination joints prepared by convex dies are more stable than flat dies. Heterogeneous joint electrochemical corrosion is intense, self-piercing riveted joints bottom material off by the stress concentration generated by the tear lines.