... steel structure, yellow zinc High strength bolts with large hex head for steel structures1.Property ... dip galvanized), Phosphate, black oxide.ect.4.Apply to standard: DIN, ISO,ANSI/ASMT,JIS,GB,NF,ectAll ... project, such as:Multi-floor & High-rise steel structure buldings, Industrial buildings,High way, Railway,Steel steam,tower, power ... other steel structure workshop frame. Hex head high strength bolts