Commodity:Cold Rolled Square Tube(Steel square pipes,rectangular pipes). Material:20,10,45,35# and Q235,16Mn, 40Cr, 35CrMo Commodity:Cold Rolled ... Square Tube(Steel square pipes,rectangular pipes).Material:20 ... , G3455, G3456 and G3454,GB 8162 & GB 8163 Steel Square Tube, Cold rolled Hollow Section