1. The inferior thick-walled seamless steel pipe is easy to fold. Folding is a kind of thick-walled seamless steel pipe surface formed by various folding lines. This defect often runs through the vertical of the whole product. The reason for folding is that poor quality manufacturers pursuing low efficiency, excessive pressure, resulting in folding of ears, rolling down, bending and fracture of products, and strength of thick-walled seamless steel tube decreased.


The surface of inferior thick-walled seamless steel pipe often has hemp surface. Pockmark is an irregular defect on the surface of thick-walled seamless steel tube due to serious groove wear. Rolling groove rolling is often the most excessive because poor quality thick-walled seamless steel pipe manufacturers pursue profits.


3. The surface of thick-walled seamless steel tube is easy to leave scars. There are two reasons: 1. The material of pseudo-thick seamless steel tube is not uniform and has many impurities. 2. The poor quality material manufacturer's guidance equipment is simple and easy to adhere to steel. These impurity occlusion rolls are easy to produce scars.