Welded steel pipe refers to a steel pipe with seams on the surface, which is made by bending and deforming steel strips or steel plates into circular, square, and other shapes and then welding them. The blank used for welded steel pipes is a steel plate or strip. Since the 1930s, with the rapid development of continuous rolling production of high-quality strip steel and the advancement of welding and inspection technology, the quality of welds has continued to improve, and the varieties and specifications of welded steel pipes have increased day by day, replacing unfinished steel pipes in more and more fields. Sewing steel pipe. Welded steel pipes have lower costs and higher production efficiency than seamless steel pipes.
Steel pipes are divided into seamless and welded pipes. Welded pipes are divided into straight seam steel pipes and spiral steel pipes. Straight seam welded pipes are divided into ERW (high-frequency resistance welding) and LSAW (straight seam submerged arc welding). The spiral pipe welding process is also submerged arc welding (SSAW for short). The difference between LSAW and LSAW is the welding seam form, and the difference between ERW and ERW is the welding process. Submerged arc welding (SAW) requires the addition of media (welding wire, flux), and ERW does not Require, ERW to be melted by medium-frequency heating. Steel pipes can be divided into two categories according to production methods: seamless steel pipes and welded steel pipes. According to the production method, seamless steel pipes can be divided into hot-rolled seamless pipes, cold-drawn pipes, precision steel pipes, thermally expanded pipes, cold-spinning pipes, and extruded pipes. Seamless steel pipes are made of high-quality carbon steel or alloy steel and are divided into hot-rolled and cold-rolled (drawn).
The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. 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, and welded pipes with different diameters can also be produced from billets of the same width. However, compared with straight seam pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower. Therefore, smaller-diameter welded pipes mostly use straight seam welding, while large-diameter welded pipes mostly use spiral welding.
Post time: Jan-29-2024