Right-angle square tube is a kind of special square tube, which is different from ordinary arc square tube for its R angle is close to 0. It is a square tube rolled from a round tube. Right-angled square tube whose R angle is not more than 1 times of the wall thickness.

Right-angle square tube: when the wall thickness＜3mm, the R angle is＜1mm;

When the wall thickness is 3-8mm, the R angle is＜2mm;

When the wall thickness is＞8mm, the R angle is ＜ 3mm, which is a sharp rectangular tube.

Classify according to the cross-sectional shape , square right-angled square tube and rectangular right-angled square tube.