Seamless steel pipe is a kind of long steel with hollow section and no seams around it. It is a kind of economic section steel,seamless steel pipe according to the different cross sectional area shape can be divided into round pipe and special-shaped pipe. Using seamless steel pipe to manufacture ring parts can improve the material utilization rate, simplify the manufacturing process, and save the material and processing time. Widely used in manufacturing structural parts and mechanical parts etc.

Welded steel pipe, also known as welded pipe, is made of steel plate  or strip steel after crimping. The production process of welded steel pipe is simple, the production efficiency is higher, the cost is more lower, the product variety is getting richer, but the general strength is lower than seamless steel pipe.

Square steel pipe is also known as square and rectangular cold bending hollow steel,referred to as square pipe and rectangular pipe. It is a kind of joint name of square pipe and rectangular pipe,that is,the steel pipe with equal and unequal side length,it is made of strip steel processed by technology.