socket cap screw Material: carbon steel, alloy steel Grade: 4.8 6.8 8.8 10.9 12.9 Surface Treatment: ZP Blacken HDG Socket cap screw1. Standard: DIN, ISO, IFI, BS, AS2. Grade: 4.8, 5.8, 6.8, 8.8.10.9.12.93: Finish: plain, black,zinc plated CR3+ CR6+., nickel, hot-dipped-galvanized.4. Material: Q195, Q235, 1035.35K,45K 40Gr 35GrMo,42GrMo...5. Size: M5-M52 (1/4"-2"), and length range is 6mm-500mm ( ...