Corrosion resistance of different metallic coatings on press- hardened steels for Automotive

摘要

The corrosion resistance of laboratory press-hardened components in aluminized, galvanized or galvannealed boron steels was evaluated through a cyclic test for the automotive industry, VDA 621-415. 22MnB5 (uncoated reference for hot stamping) and standard galvanized steel for cold forming were also included. Corrosion resistance after painting (cosmetic corrosion) was quantified by measuring the delamina-tion of electro-deposited paint on scribed panels. The rusting on their edges was used for determining the cut-edge corrosion resistance. The corrosion resistance on unpainted deformed panels (perforating corrosion) was quantified by mass losses and pit depth measurements. Zinc-coated boron steels were found to be much more resistant to cosmetic corrosion than the other materials, and slightly more resistant to cut-edge corrosion than the aluminized one. The three coated boron steels showed similar performances in terms of resistance to perforation.