... 30mm standard:GB,ASTM,JIS,DIN,API5L,API5CT steel grade:ASTM A106,A53,X42,X52,X60,PSL1 SIZETHICKNESS(mm)MATERIALSTANDARD12”6-15 ASTM A53,A106,A283 ... ,ST45-8,ST52; GB Q235,20#,10#,45#,16Mn,Q345 API PSL1,PSL2,X52,J55,K55,N80 API5L,API5CT JIS, DIN ...