What is the difference between seamless steel pipe and ordinary steel pipe
Seamless steel pipes have hollow sections and are widely used as pipes for transporting liquids. Compared with solid steel such as round steel, steel pipe is lighter in weight with the same bending and torsional strength. It is an inexpensive section steel widely used in the manufacture of structural and mechanical parts such as oil well pipes, automobile gear shafts, bicycle frames and steel frames for 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 highest performance, and are mainly used as pipelines or structural parts for conveying liquids.
2. According to the purpose of use, the supply is divided into three types:
a) Delivery according to chemical composition and mechanical properties;
b) Delivery according to mechanical properties;
c. Supply after hydraulic test. Steel pipes supplied in accordance with categories a and b shall also be hydrostatically tested when used under liquid pressure.
3. There are many types of special seamless pipes, such as boiler seamless pipes, geological seamless pipes, petroleum seamless pipes, etc.
Welded steel pipe, also known as welded pipe, is a steel pipe made of steel plates or steel strips welded by crimping. The production process of welded steel pipe is simple, the production efficiency is high, the variety and specifications are many, and the equipment is less, but the comprehensive strength is lower than that of seamless steel pipe.
Since the 1930s, with the rapid development of continuous rolling production of high-quality strip steel and the advancement of welding inspection technology, the quality of welds has been continuously improved, and the varieties and specifications of welded steel pipes have continued to increase, and so on. And more fields have replaced non-ferrous steel. Seam steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the shape of the weld.
The production process of the straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is fast. The strength of spiral welded pipe is generally higher than that of straight welded pipe.
However, compared with the straight seam pipe of the same length, the length of the weld is increased by 30% to 100%, and the production speed is slower.
Therefore, straight seam welding is mostly used for small-diameter welded pipes, and spiral welding is mostly used for large-diameter welded pipes.
