... GB SH HG APIMaterialGRB20#STEEL,A3,A234,ASTM,Q235,Q345,10#,45#,12CrMo, ,ST37 ,16Mn,Cr5Mo,15CrMoOD1/4''-24'',13mm-610mmWTSCH20 ... /-0.79mmWT ToleranceWT+-12.5%ChemicalC:<0.30%,SI:>0.10%,MN:0.29-1.06%,P:<0.035%,S:<0 ... is long, high security, highly pressurized, widely usedMin order3 tons API carbon steel pipe