Due to the limited specifications of seamless steel pipes in steel mills and the needs of end consumers, hot expanded steel pipes have emerged. The specifications and models of hot expanded steel pipes are more flexible and generally made according to customer needs. Hot expanded steel pipes are commonly referred to as hot expanded steel pipes
Seamless steel pipes, which have a low density but strong shrinkage, can be referred to as heat expanded pipes. The diameter of the pipe can be expanded by the oblique rolling or drawing method
Advantages of Hot Expanded Seamless Steel Pipes
Hot expansion is a pressure processing technology that uses hydraulic or mechanical means to apply force from the inner wall of a steel pipe to expand and form the steel pipe radially outward. Compared to hydraulic methods, mechanical methods have simpler equipment and higher efficiency, making them one of the most advanced large-diameter straight pipes in the world
The expansion process of seam welding control pipelines is adopted, and the process is as follows:
The mechanical expansion utilizes the segmented fan-shaped blocks at the end of the expansion machine to expand radially, allowing the pipe blank to achieve plastic deformation of the entire pipe length in segments in a step-by-step manner along the length direction. The process is divided into five stages
During the initial rounding stage, the sector blocks are opened until all sector blocks come into contact with the inner wall of the steel pipe. At this time, within the step size range, the radius of each point in the circular pipe of the steel pipe is almost the same, resulting in the initial rounding of the steel pipe
