Stud Bolt and Nut, Copper Pipe Tube, Spiral Wound Gasket manufacturer / supplier in China, offering ANSI B18.2.1 A193 B7 3/8 Inch Hex Bolt for Oil Pipeline, DIN 931 A193 B7 Xylan Coated Stud Bolt for Oil Pipeline, DIN W. Nr. 2.4617 Nimo28 Hastelloy B-2 Fastener with Excellent Resistance to Organic Acids and so on.