1.Thk:0.5mm-20mm 2.OD:15*15mm-600*600mm 3.Gal shs,rhs,chs 4.Build structure etc. galvanized hollow section CHS,SHS,RHS,GAL.Tianjin Haiyunda Metal Material Co.,Ltd.Rectangular hollow section/Square steel pipe,Rectangular pipeDimensionSquare pipe:15*15-600*600Rectangular pipe:10*20-600*800Thickness:0.5-20mmLength:3-12m or other customized sizesGradeQ195-235 Q345 GR.BStandardGB3091-2001 ASTM A53 ...