Square steel pipe 1.Size:15*15-400*400mm 2 ... ,X52,X56,X60,X65,X70S235J2H,S355J2H10#,20#,Q295,Q345,GrAGrB,GrC,Q235B,Q345B,SS4000.405’’-12.75’’ ... 4mm-38.4mmTubes for Structural Purposes & Ordinary PipeSquare steel tubeGB/T 3091GB/T 6728JIS G 3444ASTM A513ASTM ... PipeRoundBS 1387ISO 65ASTM A53EN 10240 GB/T 3091Q195,Q215,Q235,Q345GR.A, GR.B, GR.CSt37,st52S235J2H,S355J2H1 ... *802.0-4.75 Carbon square steel pipe