1. Folding
Stainless steel pipes produced from inferior raw materials are prone to folding. Folding refers to various fold lines formed on the surface of stainless steel pipes. This defect often runs through the entire longitudinal direction of the product. The reason for the folding is that the counterfeit manufacturers are overly pursuing high efficiency, and the amount of pressure is too large, resulting in ears in the pipe. Folding is formed during the next rolling. The folded product will crack after bending, and the strength of the stainless steel pipe will be significantly reduced. The surface of the counterfeit welded stainless steel pipe will have a pockmarked surface. The pockmarked surface is caused by the irregular uneven surface of the stainless steel material due to severe wear of the rolling groove.
2. Scarring
Stainless steel pipes produced from inferior raw materials are prone to scarring. The main causes are: ① The material of inferior stainless steel pipes is uneven and has many impurities. ② The sanitation equipment of inferior stainless steel pipe manufacturers is simple and easy to stick to steel. Impurities bite into the rollers and easily form scars.
3. Cracks
Stainless steel pipes produced from inferior raw materials are prone to cracks. The blank is adobe, which has many pores. During the cooling process of the adobe, cracks will be formed due to the effect of thermal stress, and cracks will appear after rolling.
4. Surface
The surface of the stainless steel pipe produced by inferior raw materials has no metallic luster, and the surface will be light red or similar to the color of pig iron. There are two reasons for this: ① The blank is adobe. ② The temperature of the steel pipe rolled by inferior raw materials is not standard. The steel temperature is visually measured, so it cannot be rolled according to the specified austenite area, and the performance of the stainless steel pipe will naturally not meet the standard.
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