What is the difference between seamless steel pipe and welded steel pipe?

　　Seamless steel pipe does not have welds, because it is different from the construction technology of welded steel pipe.

　　Seamless steel pipe is manufactured at 2200 F high temperature, which belongs to hot rolling. Using continuous casting slab or blooming slab as raw material, a hole is punched out in stainless steel billet, so that the wall thickness of seamless steel pipe is uneven and eccentricity is high. So the wall thickness difference of DIN2391 Cold Rolled Precision Carbon Seamless Steel Pipes is bigger than that of seamless steel pipe. There is no welded steel bar on the inner wall of steel pipe.

　　Welded steel pipe is usually completed by cold rolling, high frequency welding, forming and other processes. It's a kind of sewed pipe. The seamed tube is made of cold rolled sheet and hot rolled coil is used as raw material. Usually the tolerance of wall thickness is very small, and the wall thickness of the whole circumference is very uniform. In addition, welded steel pipe can be divided into straight welded steel pipe and spiral welded steel pipe.

　　Generally speaking, seamless steel pipes are pulled out directly with ingots, and welded pipes are made of steel rolled and welded.