... tube: standards and grades:GB5310,GB3087,10#,20#,20G,20MnG,12Cr1MoVG,15CrMoG ASTM A335(P1/P11/P12/P2/P22/P5/P9 pressure ... boiler tube:Application:Generally for boilers and heat exchangersDimensions,mechanical properties ... requirementsPacking:bundlesomerwith or without edge protector,as per custtomers' requirement pressure boiler tube