LSAW pipes are produced from steel plates, while spiral welded pipes are produced from hot rolled coils. The rolling process of the hot strip mill has a series of advantages, and has the ability to obtain the metallurgical process to produce high quality pipeline steel. For example, a water cooling system on the output stand to accelerate cooling allows the use of low alloy compositions to achieve special strength grades and low temperature toughness, thereby improving the weldability of the steel. But this system is basically absent in steel plate production plants. The alloy content (carbon equivalent) of coils tends to be lower than that of similar grades of steel, which also improves the weldability of spiral welded pipes.
It should be noted that, since the rolling direction of the spiral welded pipe is not perpendicular to the axis of the steel pipe (the clipping depends on the helix angle of the steel pipe), the rolling direction of the steel plate of the straight seam steel pipe is perpendicular to the axis of the steel pipe. The crack resistance of we
