Duplex Steel Fasteners, ASME B18.2.1 Hex Bolts ASME B18.2.2 Hex Nuts ASME B18.22.1, Stud Bolt, Hex Bolt, Hex Bolt with partial thread, Hex Bolt with full thread, threaded Rod, U-Bolt, Hex Socket Cap Screw, Hex Socket Cap Screw, Hex Socket Cap Screw, Hex. Pipeline Equipment Co., Ltd.