??Application criterion 1?¢Design and manufacture£oto ANSI B16.34;API602 2?¢Size of coupling end: (1).Size of socket joint hole:to ANSI B16.11,JIS B23.6 (2).Size of threaded end :to ANSI B1.20.1:BS21:JIS BO203:S107/1 3?¢Valve inspection and test£oto API 598 4?¢Structure characteristics£oB.B;OS&Y OR W.B;OS&Y 5?¢Material:to AIS/ASTM 6?¢Materiare fo main body£o A105£?F5£?F11£?F22£?304£?304L£?316£?316L£?LF2.etc