The small-diameter welded pipe
is also called small-diameter welded steel pipe, which is a steel pipe made by welding a steel plate or a strip steel after being crimped. The production process of small diameter welded pipe is simple, the production efficiency is high, there are many varieties and specifications, and the equipment cost is small, but the general strength is lower than that of seamless steel pipe
. Since the 1930s, with the rapid development of continuous production of high-quality strip steel and the improvement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of small-diameter welded pipes have been increasing and replaced in more and more fields seamless steel pipe. Welded steel pipe is divided into straight seam welded pipe and spiral welded pipe according to the form of weld.
The blanks used for small-diameter welded pipes are steel plates or strips, which are divided into furnace-welded pipes, electric-welded (resistance-welded) pipes, and automatic arc-welded pipes due to their different welding processes. There are two types of welded pipe: straight seam welded pipe and spiral welded pipe. Because of its end shape, it is divided into round welded pipes and special-shaped (square, flat, etc.) welded pipes.
The production process of small-diameter welded pipe is simple, high production efficiency, low cost and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Welded pipes with larger diameters can be produced from narrower billets. Welded pipes with different diameters can also be produced with billets of the same width. However, compared with the straight seam pipe of the same length, the weld seam length is increased by 30 to 100%, and the production speed is lower. Therefore, the smaller-diameter welded pipes are mostly straight seam welded, and the large-diameter welded pipes are mostly spiral welded.