... of heat treatment. 3, Excellent team worker, service for you. center bolt 1. Material: 40Cr2.Quality Grade: 8.8,10.9 ... .Finishing: Bake Paint, Black Oxide, Zinc Plated, Phosphate, Electrophoresis, Dacromet, with high temperature treatment.6.We can make products strictly according ... is highly appreciated. Looking forward to establish Long-Term Cooperation with you.