Fake and inferior steel pipes
are prone to folding. Folds are various 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 folding is that the counterfeit and inferior manufacturers pursue high efficiency, the reduction is too large, and the ears are formed. Folding occurs during the next rolling, and the folded product will crack after being bent, and the strength of the steel pipe will be greatly reduced.
Fake and inferior steel pipes often have pockmarked surfaces. The pitted surface is the irregular unevenness on the surface of the steel pipe caused by the serious wear of the rolling groove. Due to the pursuit of profit by the manufacturers of counterfeit and shoddy steel pipes, the rolling grooves often exceed the standard.
Fake and inferior steel pipes are prone to scarring on the surface. There are two reasons: 1. The material of fake and inferior steel pipes is uneven and there are many impurities. 2. The guide and guard equipment of the fake and inferior material manufacturers are simple and easy to stick to the steel. These impurities are prone to scarring after biting the roll.
The surface of the fake and inferior material is prone to cracks. The reason is that it is blank in adobe, and adobe has many pores. During the cooling process, the adobe is subjected to thermal stress, resulting in cracks. After rolling, there are cracks.
Fake and inferior steel pipes have no metallic luster and are light red or similar to pig iron for two reasons. The blanks are adobe. 2. The rolling temperature of fake and inferior materials is not standard, and their steel temperature is measured visually so that the rolling can not be carried out according to the specified austenite area, and the performance of the steel pipe will naturally fail to meet the standard.
The horizontal bars of the fake and inferior steel pipes are thin and low, and there is often a phenomenon of unsatisfactory filling. The reason is that to achieve a large negative tolerance, the reduction amount of the first few passes of the finished product is too large, the iron shape is too small, and the hole shape is unsatisfactory.