GB/T 6728-2017

This standard specifies the ordering content, classification, designation, cross-section, dimensions and allowable deviations, length and allowable deviations, appearance, weight and allowable deviations, technical requirements, and marking examples of cold-bent hollow sections for structural use. This standard applies to round, rectangular, and square cold-bent hollow sections (hereinafter referred to as hollow sections) produced from cold-rolled or hot-rolled steel plates and steel strips on continuous roll cold-bending machines, and also applies to continuous hot-dip galvanized hollow sections. However, it does not apply to hollow sections produced by methods such as drawing, stamping, and bending, or hollow sections formed by welding galvanized steel plates and steel strips after cold bending. The hollow sections specified in this standard are mainly made by high-frequency resistance welding, but argon arc welding or other welding methods can also be used.