Seamless steel pipe has a hollow cross-section and is widely used as a pipeline for transporting fluids, such as pipelines that transport oil, natural gas, gas, water, and certain solid materials. Compared with solid steel such as round steel, steel pipe is lighter in weight when it has the same flexural and torsional strength. It is an economical cross-section steel and is widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill rods, automotive transmission shafts, and bicycles. Steel pipes and other scaffolds used in building construction to make ring-shaped parts can improve material utilization, simplify manufacturing processes, save materials and processing hours, and have been widely used in steel pipes.
Compared with solid steel such as round steel, seamless steel pipe is lighter in weight when it has the same bending and torsional strength. It is an economical cross-section steel. It is widely used in manufacturing structural parts and mechanical parts, such as petroleum drill rods and automobile transmission shafts. , Bicycle frames and steel scaffolding used in building construction.
Carbon steel seamless pipeis widely used. General purpose seamless steel tubes 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.
Oil Line Seamless Steel Pipe
2. It is divided into three categories according to different uses:
a. Supply according to chemical composition and mechanical properties;
b. Supply according to mechanical properties;
c. Supply according to hydraulic test. For steel pipes supplied according to categories a and b, if they are used to withstand liquid pressure, a hydraulic test is also required.
3. Special-purpose seamless pipes include boiler seamless pipes, geological seamless steel pipes, and oil line seamless steel pipes.
Welded steel pipe, also called welded pipe, is a steel pipe made of steel plate or steel strip after being crimped and welded. The production process of welded steel 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 high-quality strip continuous rolling production and the improvement of welding and inspection technology, the quality of welds has been continuously improved, and the variety of welded steel pipes has increased, and has replaced Seam steel pipe. Welded steel pipe is divided into straight seam welded pipe and spiral welded pipe according to the form of weld.
The production process of 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 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 straight seam pipes 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.