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What is the difference between seamless steel pipe and ordinary steel pipe

Seamless steel pipe is long steel with a hollow section and no joints on the periphery.

1.Seamless steel pipes have a hollow section and are used in large quantities as pipes for conveying fluids. Compared with solid steel such as round steel, steel pipes have the same bending and torsion strength and lighter weight. They are economical cross-section steels and are widely used in manufacturing structures. Parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames, and steel scaffolding used in construction.
Seamless steel pipes are widely used. General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel, or alloy structural steel, with the largest output, and are mainly used as pipelines or structural parts for conveying fluids.

2. According to different purposes, it can be supplied in three categories:
a. Supply according to chemical composition and mechanical properties;
b. According to mechanical performance;
c. According to the water pressure test supply. Steel pipes supplied according to categories a and b, if used to withstand liquid pressure, shall also undergo a hydraulic test.

3. Special-purpose seamless pipes include seamless pipes for boilers, seamless pipes for geology, and seamless pipes for petroleum.
Welded steel pipes, also called welded pipes, are steel pipes made by welding steel plates or steel strips after crimping. Welded steel pipe has a simple production process, high production efficiency, many varieties and specifications, and less equipment, but the general strength is lower than seamless steel pipe.

Since the 1930s, with the rapid development of high-quality strip, continuous rolling production, and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have increased, and they have replaced non-products in more and more fields. Seam the steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of welds.

The longitudinal welded pipe has a simple production process, high production efficiency, low cost, and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. A narrower blank can be used to produce welded pipes with larger pipe diameters, and a billet with the same width can be used to produce welded pipes with different pipe diameters. However, compared with the straight seam pipe of the same length, the weld length is increased by 30-100%, and the production speed is lower. Therefore, most of the smaller diameter welded pipes adopt straight seam welding, and the large diameter welded pipes mostly adopt spiral welding.