steel tube : O.D. 20- 480mm, W.T. 2- 60mm. ASTM A335, ... , JIS G3458, G3467, etc. Material Carbon Steel, Alloy steel. steel tube Standards and Grades:GB5310, GB3087, 10#, 20#, 20G, 20MnG,12Cr1MoVG ... / 22/ 23/ 24/ 25/ 26) JIS G3462 Alloy Steel for Boiler and Heat Exchanger Tubes (STBA12/ 13/ 20/ 22/23) JIS ...