... : 3M,6M,12M,Specification: ASTMA315B,ASTMA53A,ST37Usage: gas transport,boiler,heat exchangerStandard: ASME, ANSIGrade: A53B, API J55, API K55, Q195, Q215 ... ,AND,SO,ON. a)O.D: 21.3mm-711mm b) wall thickness:0.5-55mmseamless steel pipeSteel standard : ASTM.JIS,DIN ...