Alloy Steel 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 ASTM / ASME A213 T11 T12 T5 T9 T91 T23 T22 Size: OD: 20-1, 067mm WT: 1-80mm Stanard: GB/ DIN/ JIS/ ASTM FORM SEAMLESS / ERW / WELDED IN ROUND & SQUARE .