... steel structure project; A leading fastener manufacturer in China ASTM A325 Hex head high strength boltASTM A325/GB1228 high strength bolts with ... , black oxide.ect.4.Apply to standard: DIN, ISO,ANSI/ASTM,JIS,GB,NF,ectAll our products are used for steel ... China, welcome you to our factory for business Business negotiation! ASTM A325 Hex head high strength bolt