1. Fake rectangular tubes are prone to folding. Folds are various fold lines formed on the surface of rectangular tubes. Such defects often run through the entire product in the longitudinal direction. The reason for the folding is that the fake and inferior manufacturers are pursuing high efficiency, the reduction is too large, and ears are generated. When the next rolling is performed, folding occurs. The folded product will crack after bending, and the strength of the steel is greatly reduced.
2. The appearance of shoddy rectangular tubes often has numbness. The matte surface is a defect of irregular unevenness on the surface of the steel due to the serious wear of the rolling groove. Because the manufacturers of fake and inferior rectangular tubes are pursuing profits, it often occurs that the rolling of grooves exceeds the standard.
3. The surface of fake and inferior rectangular tubes is prone to scarring. There are two reasons for this: (1). The material of the fake and inferior rectangular tubes is uneven and there are many impurities. (2). The counterfeiting equipment of the inferior manufacturer is simple and easy to stick to steel, these impurities
