Method for repairing of adhesive-bonded steel

With an increase in the use of advanced high strength steels in vehicle architectures, materials joining issues (e.g., performance and manufacturability) have become increasingly important. Among the various joining methods, adhesive bonding is increasingly used in automobile manufacturing. Successful implementation of adhesive bonding for vehicle welding application requires not only the knowledge of issues related to processing and design but also a practical method to repair the bonded joints.In this study, a plug stud welding (PSW) process is proposed to repair the bonded steels. The process is as follows: (a) punching a hole at the first metal sheet; (b) inserting slug into hole; (c) and (d) passing electrical arc through slug of sufficient intensity to promote melting at the interface between the first and second metal sheets and slug, thereby (e) securing the metal workpiece. The repaired bonded DP780 steel samples were fabricated and tested. Test results were compared with that of conventional resistance spot welds. The results show that repaired bonded steels had comparable tensile and fatigue strengths to conventional spot welds. These results suggest that plug stud welding process is feasible for repairing the adhesive-bonded steels in vehicle assembly plants and collision body shops.