The difference between erw and seamless black steel pipe

ERW

Electric resistance welded (ERW) steel pipe is formed by rolling steel and then welding it longitudinally along its length. Therefore, ERW steel pipe has a welded joint in its cross section.

Seamless black steel pipe

Seamless pipes are manufactured by extruding metal to the desired length. Therefore, they do not have any joints in the cross-section of their entire length.





Comparing ERW and Seamless Black Steel Pipe


There are several differences between ERW steel pipe and seamless steel pipe. ERW pipes are used to transport liquids such as fuels, gases, etc., regardless of their pressure, making them one of the most typical delivery pipes in the world. Seamless pipe, on the other hand, is a square or rectangular shaped steel pipe without seams around it, with a hollow cross-section, used for conveying liquids and making structural and mechanical parts, due to its high bending and torsional strength and impressive Incredibly light. Generally speaking, ERW and seamless steel pipe are very different in their usage.


The biggest difference between ERW pipe and seamless steel pipe is that ERW pipe has weld seam, which is the same as welded steel pipe, but seamless black steel pipe does not, nor does welded steel pipe. In addition, the welding line of ERW pipe is the key to the quality of ERW steel pipe. The harder the weld line of the ERW pipe is to identify, the higher the quality of the ERW pipe.


There are two methods of eliminating welds: geometrically seamless and physically seamless. Geometric seamless is to eliminate internal and external burrs, and physical seamless is to take measures to make the base metal and metallographic structure uniform. It seems to be more complicated to achieve, but which can be achieved.


Compared with the processing technology of ERW pipe, the processing technology of seamless steel pipe is much simpler. There are two completely different processing techniques: cold drawing and hot rolling. Compared with hot rolling, the process flow of cold drawing is more complicated. Moreover, from the appearance point of view, the stainless steel cold-drawn pipe is shorter than the hot-rolled pipe, and the wall thickness of the cold-drawn seamless stainless steel pipe is generally smaller than that of the hot-rolled pipe. More importantly, the hot rolling process requires high temperature, which reduces the deformation resistance, thereby achieving large deformation. Generally speaking, the processing of ERW pipe and seamless steel pipe is very different because of the different appearance.


In general, although both ERW pipes and seamless steel pipes play an important role in social construction like welded steel pipes, ERW pipes and seamless pipes have different appearances, different uses, and different progress.

Read more : seamless vs welded pipe