Fluid Pipe, Seamless Steel Pipe for Fluid Transportation

Fluid pipes


Fluid pipes are pipes specially used for conveying media with fluid properties.
Medium with fluid properties, in addition to liquid media such as water, oil, and solution, solid media such as cement, grain, and coal powder can also flow under certain conditions.

The fluid tube can be made of steel, copper, titanium and other non-ferrous metals, or even plastic and other non-metallic materials.

The fluid pipe must have a hollow cross-section, and it can also be square, triangular or any other shape. Some equipment is restricted by conditions, and rectangular pipes must be used, but most still use round pipes. The round tube has the smallest perimeter/area ratio in all geometric sections, that is, the largest internal section can be obtained under the same amount of material.

Steel pipes are also an indispensable material for various conventional weapons. Gun barrels and barrels are all made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to different cross-sectional area shapes. Because the circle area is the largest under the condition of equal circumference, the circular pipe can transport more fluids, and is widely used to transport oil, natural gas, gas, water and certain solid materials.

In addition, when the ring section bears internal or external radial pressure, the force is relatively uniform. Therefore, most steel pipes are round pipes. However, round pipes also have certain limitations. For example, under flat bending conditions, round pipes are not as strong as square and rectangular pipes. Some agricultural machinery frameworks, steel and wood furniture, etc. often use square and rectangular pipes. According to different purposes, special-shaped steel pipes with other cross-sectional shapes are required. 

(Remarks: The current technology continues to improve. Fluid steel pipes may not necessarily be seamless, but may also be seamless steel pipes. This process has been approved for use in low and medium pressure boilers and fluid pipelines. Customers must order fluid steel pipes in the industrial contract. It indicates that the welded pipe is seamless, and the fluid steel pipe includes the steel pipe of these two processes, but the delivery price is different)
Due to its low cost and high strength, steel pipes are widely used in fluid transportation in modern society. According to its production process, steel pipes are divided into two categories: seamless steel pipes and welded pipes. Among them, welded pipes are divided into high frequency straight seam welded pipes (ERW pipe), spiral welded pipes (SSAW pipe), submerged arc welded pipes (UOE/LSAW), etc. In the past, seamless steel pipes were traditionally used for fluid pipes. With the development and progress of material science, forming technology, and unit equipment, welded pipes have been greatly developed. 

Welded pipes have the advantages of better wall thickness uniformity, higher precision, less energy consumption, and higher production efficiency than seamless pipes. The demanding oil and gas pipeline (API standard) used to be almost 100% seamless pipes. Today, in the United States, More than 95% of developed countries in Japan and Europe have been replaced by welded pipes.
When welded pipe is used as a fluid pipe, it has different requirements from ordinary steel pipe:

1. Welding seam is not allowed to leak. For welded pipes required by APIs, ultrasonic flaw detection and water pressure test are also required for the weld of each welded pipe;
2. For transporting corrosive chemical solutions, all steel pipes must be treated with internal corrosion protection;
3. All fluid pipes need to remove internal burrs to reduce fluid transport resistance.

Seamless pipes for fluid transportation

Seamless pipes for fluids are seamless steel pipes specially used for transporting various fluids such as water, oil, natural gas, steam, chemical media, etc. With their characteristics of no welds and high strength, they have become the core pipe material in the fields of petrochemicals, municipal water supply and drainage, energy transportation, machinery manufacturing, etc. From the manufacturing process point of view, it uses steel ingots as raw material and is made through processes such as perforation, hot rolling, cold rolling or cold drawing. There is no welding link in the entire process, which avoids the hidden dangers of corrosion and cracking at the welds. It can adapt to the transportation needs of high pressure, high temperature or corrosive fluids. 

In terms of performance, seamless pipes for fluids have outstanding advantages: first, they have strong pressure resistance and can withstand higher working pressures, making them suitable for long-distance high-pressure fluid transportation; Secondly, the inner wall is smooth and the fluid resistance is small, which can reduce the energy consumption of transportation and reduce the risk of impurity accumulation, thus ensuring the transportation efficiency; Third, it has good sealing performance. The weld-free structure combined with flanges, threads and other connection methods can effectively prevent fluid leakage and is especially suitable for transporting flammable, explosive or toxic media.

In terms of application scenarios, it covers a wide range: in the oil industry, it is used for crude oil and natural gas pipelines; in the municipal field, it is used as the core pipe material for water supply, drainage and heating pipelines; in the chemical industry, it is responsible for the transportation of corrosive fluids such as acid and alkali solutions and solvents; in the power industry, it is used for boiler steam and cooling water circulation pipelines.

Read more: Advantages of Seamless Pipes in Pipeline Transportation