Applied Standard 1. Design and Manufacture: According to Standard:ANSI, B16.34,API,602. 2. Size of the Junction End: <1> The size of bell and spigot hole is designed according to standard: ANSI, B16.11,JIS, B2306. <2> The size of the threaded end is designed according to standard ANSI1 B1.20.1 B21 ISO7/1 JIS B0203. 3. Testing of Valves:According to API 598. 4. Structure Characteristics:B.B; OS&Y or W.B;OS&Y. 5. Materials:According to the requirements of AISI/ASTM. 6. Main Materials A105;F5;F11;F22;304;304L;316;316L;Lf2 etc.