... ,GB6479-2000,GB9948-2006 Material St35.8, St44 ,St52, 20Mn2 ,10, 20,35,45, 16Mn,Q345,20G,20MnG, 25MnG,15CrMoG,12Cr1MoVG, J55 ... : 4~80mm Outer Diameter: 27~426mm Length: 5.8~13m(as your requirment) Material: 20#, 45#, 16Mn, Q195, Q235, Q345B, 30CrMo, 42CrMo ... , WT4-80mm. The materials of the products are as follows:20#,45#,16M, 27SiMn,15CrMo,30CrMo,34CrMo4,12Cr1MoV,J55,K55, N80 ...