1. Low-quality thick-walled seamless steel tube is easy to fold. Folding is the surface of thick-walled seamless steel tube, which is formed by various folding lines. This defect usually runs through the vertical direction of the product. The reason for folding is that the manufacturer's poor quality, high efficiency and excessive pressure cause ears to fold down, the folded products will break, and the strength of thick-walled seamless steel tube will decrease.


2. The surface of seamless steel tube is thick and beautiful. Pockmark is an irregular surface defect of thick-walled seamless steel pipe caused by severe wear of grooves. Groove rolling is often the most extreme because of the pursuit of profit losses for manufacturers of thick-walled seamless steel tubes.


3. The surface of thick-walled seamless steel tube is easy to produce scars. There are two reasons: 1. Pseudo-thick seamless steel pipe has uneven material and many impurities. 2. Manufacturers of inferior materials are not good at guiding equipment and sticky steel. These impurities bite the drum and cause scars easily.