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 ... .D.20-480mm, W.T. 2- 60mm. Application: Generally for boilers and heat exchangersDimensions, Mechanical properties, Chemical compositions: Refer to ASTM ...