Bolt, Nut, Customized Fastener manufacturer / supplier in China, offering DIN912 Hex Socket Head Cap Screw Sems with Flat & Spring Washer Black Oxide M3 M4 M5 M6, ASTM A193 B7 Heavy Hex Bolt En 10204 3.1 Mtr Black Oxide 1/2"-4" Dia High Temp Petrochemical Flange, ASTM A193 B7 Heavy Hex Bolt PTFE Coated 125ksi Tensile -40°C to 593°C En 10204 3.1 Petrochemical Valve & Flange and so on.