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with the requirements of vehicle lightweight and safety performance, dual phase steel is more and more widely used in vehicles. However, the stamping of the sheet has attracted more attention due to the increased use of dual-phase steels in auto parts. In this paper, the surface morphology, composition, surface kinetic friction coefficient, and plate thickness change rate of stamping plates were detected, calculated, and analyzed respectively. Based on solving the problem of the dezincification defect of DP590 alloyed hot-dip galvanized dual-phase steel during stamping. In addition, the stamping die was also investigated and analyzed, The results showed that the stamping die has deteriorated beyond the service life, resulting in the reduction of the adaptability between the die and the material. More importantly, the low Fe content and high dynamic friction coefficient of the surface of the stamped plate made the zinc layer unable to keep up with the tensile deformation of the substrate during stamping, which was the main factor for the lamellar detachment at the interface between the zinc layer and the substrate. By updating the dies and improving the plate design, the stamping dezincification defects of the sheet have basically disappeared.

The bake hardening steel can better solve the contradiction between stamping formability and dent resistance of steel plates due to the lower strength and higher formability during stamping, as well as the advantages of increased strength after coating and baking. However, bake hardened steel can suffer from cracking problems in the stamping process. In this paper, the mechanical properties and stamping properties of the bake hardening steel were tested, and the production process was also analyzed. The results showed that the material has aged due to the long storage time, decreasing elongation. The main reason for stamping cracks was the reduction of the amount of oil applied to the material anti-rust oil. When the material was stored for a long time, the anti-rust oil on the surface of the steel plate volatilized, resulting in cracks in the stamping. Based on the above research, the material delivery time was strictly controlled. The cracks disappeared by supplementing and oiling the materials that had been stored for more than five months. The stamping performance of the bake hardening steel is improved.

With the development of automobiles toward lightweight and comfort, the production of auto parts has higher and higher requirements for stamping materials and parts forming quality. During the stamping and manufacturing process of the passenger car tailgate inner plate, the tailgate inner plate has many cracks, concealed cracks, and other defects. In this paper, the fracture morphology of the defect section was observed, and the composition and mechanical properties were measured. At the same time, the production process of the steel plate and the working condition of the stamping die were analyzed. The results show that the cracking and concealed cracking defects of stamping sheets are mainly caused by the inclusion of die and sheet. Through the adjustment of the plate production process and mold, the cracking and concealed cracking defects disappeared. This work also provides a reference for the solution to stamping cracking defects in the future.

The intelligence and automation of grounding wire information management are improved by the grounding wire management system based on network communication in maintenance of catenary, but the security problem of information transmission existed in this system. For this reason, the SM2 algorithm is used to digitally sign the grounding wire information, and ensure it can not be tampered and non-repudiation. Under the C/S architecture, the grounding wire information management system with digital signature technology is established. The server realizes the information interaction between the grounding wire monitoring unit and the client. The client visually displays the status, location, and picture information of the grounding wire through the visual interface. The results show that the application of the SM2 digital signature technology for the grounding wire information management system insure the security of the grounding wire information.