In all steel pipes, ASTM A53 seamless steel pipe
occupies a large proportion, but in actual production, the seamless steel pipe is often used to control rolling and cooling technology. It is easy to control the cooling process caused by the uneven defects of the cooling plate, which seriously affects the quality of the product and the contract cash. The surface wave is one of the more serious ones.
The wave defects on the sides of seamless steel tubes are caused by uneven lateral cooling. Field tracking showed that there was obvious "ribbon supercooling" area on both sides of the side wave plate. The transverse cooling caused by inhomogeneous factors is:
1) there is a transverse temperature difference between the center and side of the seamless pipe
2) there is a large temperature difference between the middle and the edge of the seamless steel tube during the controlled rolling process.
3) the "CVC" rolling process is used in the finishing mill, which is caused by the difference between the two sides of the steel plate and the extension part of the middle, which leads to the internal stress of the steel plate, which can not reach the bilateral degree. But it increases further during the subsequent cooling process.
4) in controlling the cooling process of seamless steel tubes, not only the structural changes will take place along with the temperature changes, but also the complex stress changes will happen.