What Is The Difference between Seamless And ERW Pipes?

Erw pipe is a steel pipe with welds made by erw tube mill, while seamless pipes are mostly cold-drawn steel pipes without welds, which usually have the disadvantage of uneven wall thickness.

From their definition, we can see that one has no gaps and the other has gaps. And the seamless steel pipe can be seen from the outer surface, there is no gap in the whole body; the welded steel pipe has a welding gap. The price of seamless steel pipes is generally higher than that of welded steel pipes. Seamless steel pipes are generally used in factories; welded steel pipes are generally used in construction. The pressure resistance of seamless steel pipes is higher than that of welded steel pipes.

Seamless And Welded Pipe Difference

(1) Different In Nature

a. Seamless steel pipe: a steel pipe made of a single piece of metal with no seams on the surface.

b. Welded steel pipes: steel strips or steel plates that are bent and deformed into round or square shapes and then welded into steel pipes with seams on the surface.

(2) The Characteristics Are Different

a. Seamless steel pipe: the maximum diameter is 650mm, and the minimum diameter is 0.3mm. According to different uses, there are thick-walled pipes and thin-walled pipes.

b. Welded steel pipes: T-welded steel pipes have strong corrosion resistance in acidic environments when they contain Ni. In environments containing sulfuric acid or hydrochloric acid, the higher the Ni content in the T-welded steel pipes, the stronger the corrosion resistance. Under normal circumstances, only adding Cr to the T-welded steel pipe can prevent corrosion.

(3) The Role Is Different

a. Seamless steel pipes: seamless steel pipes are mainly used as petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler pipes, bearing pipes, and high-precision structural steel pipes for automobiles, tractors, and aviation.

b. Welded steel pipes: electric welded steel pipes are used in oil drilling and machinery manufacturing, etc.; furnace welded pipes can be used as water gas pipes, and large-diameter longitudinally welded pipes are used for high-pressure oil and gas transportation; spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc.

(4) Manufacturing Process Different:  

a.Seamless Pipes: Seamless pipes are manufactured without any welding or joining process. They are produced by piercing a solid billet of steel and then drawing it over a mandrel to form a hollow tube. This process ensures a uniform structure without any seams. 

b.ERW Pipes: ERW pipes are manufactured by rolling metal sheets through a series of rollers that form it into a cylindrical shape. The edges of the sheet are then welded together using electric resistance welding.