Alloy Steel Tube Alloy Steel Tube A213, T5, T9, T22, T11, T12, T91 ( Model Number : A213, T5, T9, T22, T11, T12, T91 ) Click to enlarge image Alloy Steel Alloy Steel Tube A213, T5, T9, T22, T11, T12, T91 ASTM / ASME A 335 GRP 1 , P 5 , P 9 , P 11 , P 12 , P 22 , P 23 , P 91 ASTM / ASME A 691 GR 1 CR , 1 1/ 4 CR , 2 1/ 4 CR , 5 CR , 9CR , 91 SIZE: OD 20-1, 067mm WT 1-80mm Standard GB/ DIN/ JIS/ ASTM FORM SEAMLESS / ERW / WELDED IN ROUND & SQUARE .