20# carbon steel pipe 1.Standard:ASTM,AISI,EN,DIN,BS ... ,GB8163-1999,GB3087,GB6479-86,ASTM A106,A53,A210,DIN17175Material10#,20#,45#,16Mn,14MnNb,20G,ST35.8,A106B,12CrMo,15CrMo,20CrMo ... you have any other questions,pls contact me without hesitate. 20# carbon steel pipe