¡ö 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