Shoddy steel pipes
are prone to folding. Folding is a variety of fold lines formed on the surface of the steel pipe, and this defect often runs through the longitudinal direction of the entire product. The reason for the folds is that the counterfeit and inferior manufacturers pursue high efficiency, and the reduction is too large, resulting in ears, which will cause folds in the next rolling process, and the folded products will crack after bending, and the strength of the steel pipe will drop greatly.
The appearance of fake and inferior steel pipes often has pockmarks. A pockmarked surface is the defect of irregular unevenness on the surface of the steel pipe due to serious wear of the rolling groove. Because manufacturers of fake and inferior steel pipes want to pursue profits, the groove rolling precision often exceeds the standard.
The surface of fake and inferior steel pipes is prone to scarring. There are two reasons: 1. The material of fake and inferior steel pipes is uneven and has many impurities. 2. The guides and guards of fake and inferior material manufacturers are poorly equipped and easy to stick to steel. These impurities are prone to scarring after biting the roll.
Cracks are easy to occur on the surface of fake and inferior materials. The reason is that it blank is in adobe, and adobe has many pores. During the cooling process, the adobe is subjected to thermal stress and cracks occur. After rolling, there are cracks.
False and inferior steel pipes have no metallic luster, are light red, or have a color similar to pig iron, for two reasons. 2. Its blank is adobe. 2. The rolling temperature of counterfeit and inferior materials is not standard. Their steel temperature is measured visually so that rolling cannot be carried out according to the specified austenite region, and the performance of the steel pipe will naturally fail to meet the standard.
The horizontal ribs of fake and inferior steel pipes are thin and low, and the phenomenon of insufficient filling often occurs. The reason is that to achieve a large negative tolerance, the reduction in the first few passes of the finished product is too large, the iron shape is too small, and the hole shape is not full.