(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......
1) Design standards: API 600, API 6D, JIS B2073, JIS B2083
2) Inspection and test standards: API 598, JIS B2003
3) Face-to-face: ASME / ANSI B16.5, JIS B2002......