Fluid Steel Tubes

Fluid pipes are hollow cross section, no welded joint from start to finish. Steel tube with a hollow cross-section, for a large number of pipe conveying fluid pipeline to transport oil, natural gas, coal gas, water and some solid materials.

Compared to solid steel such as steel pipes and round steel in flexural torsional strength the same, lighter, is an economic section steel, widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive transmission, bike frame and steel used in construction scaffolding.

Having the nature of the fluid medium, in addition to the liquid medium such as water, oil, solution, etc., cement, grain, coal and other solid media, under certain conditions, can also be mobile.

Fluid tubes made of steel, copper, titanium and other non-ferrous metals manufacturing, and even can be manufactured from plastic and other non-metallic materials. Must be fluid tube having a hollow cross-section, but can also be square, triangular or any other shape, and some of the equipment subject to conditions, it must be used a rectangular tube, but most or using round tube. Tube in all geometric cross-section having a minimum perimeter / area ratio of the maximum internal cross-section, i.e. under conditions using the same amount of materials can be obtained.

Steel pipe due to its low cost, high strength, in the modern society, the fluid delivery to be widely applied. Steel pipe into seamless steel pipe and welded pipe two categories according to their production process, which welded pipe is divided into ERW (ERW), spiral welded pipe (SSAW), submerged arc welded pipe (UOE). In the past, the fluid tubes to the traditional use of seamless steel pipe, materials science, the molding process, the development and progress of the crew and equipment, welded pipe has been a great development.

Welded pipe has the advantages of better than seamless pipe wall thickness uniformity, high precision, low energy consumption, high production efficiency, demanding oil and gas pipeline (API standard), almost one hundred percent use of seamless pipe, today in the United States, Japan, Europe and the developed countries, more than 95% have been welded pipe replaced.

With ordinary steel pipe, the welded pipe for transporting fluid tubes have different requirements:

• the weld is not allowed to leak. Requirements for API like welded pipe, also requires ultrasonic inspection and hydrostatic test of each welded pipe welds;
• for conveying a corrosive chemical solution, all pipe must be carried out to the inner wall of anti-corrosion treatment;
• fluid tubes need to remove the inner burr in order to reduce the resistance to fluid transport.

Standards and grades of pipe for conveyance of fluid

• ASTM A53M: Gr.A, GR.B
• ASTM A106M: Gr.A, Gr.B, Gr.C
• GB/T 8163: 10#, 20#, Q345A, Q345B, Q345C, Q345D, Q345E
• JIS G3454: STPG 370, STPG 410
• JIS G3455: STS370, STS 410, STS 480
• JIS G3456: STPT 370, STPT 410, STPT 480

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.

The difference between structural tubes and fluid tubes

Structural tube

Structural tube is a general structural steel tube, referred to as structural tube. It is suitable for seamless steel tubes for general structures and mechanical structures. The most common material is carbon steel, which can be divided into two types: ordinary carbon structural steel and high-quality carbon structural steel. There are many uses and a large amount of use. It is mainly used in railways, bridges, and various construction projects to manufacture various metal components that bear static loads, as well as unimportant mechanical parts that do not require heat treatment and general weldments.
Structural seamless tubes are steel tubes used to build various structures because they are used to build various structures that need to achieve several properties.

1. The pressure bearing capacity must be good, and no fracture can occur, otherwise, once an accident occurs, the construction of the entire project will be affected.
2. Easy to build. It only needs to be built according to the general standard, and it can be completed quickly.
3. Durable, it can be used for a long time after the project is completed, and it will not be damaged and worn for a long time.

Fluid tube

The fluid tube standard is suitable for general seamless steel tubes for conveying fluids. Fluid seamless tubes are steel pipes used to transport various liquids and gases such as oil, natural gas, natural gas and water. Because it is used for transportation, fluid pipelines also have their own remarkable characteristics.

1. Good air tightness, no leakage is allowed during transportation, otherwise the gas will leak, and the consequences will be disastrous.

2. Prevent corrosion, because many transported objects are corrosive, if corrosion occurs, the entire project will be affected.

3. The smoothness of the pipe is very demanding, and it needs to meet the requirements before it can be made into a fluid pipe.

First, strictly speaking, they cannot be shared. Structural tubes require good pressure bearing capacity, while fluid pipes require good sealing performance. Therefore, the uses of the two are very different. Try not to use the wrong area.

Secondly, structural pipes have high requirements on cost, otherwise some steel tubes are not up to standard in terms of corrosion resistance or pressure bearing capacity, and are easily damaged. If water and food are transported by fluid pipelines, the hygienic requirements are stricter. It can be shared under special circumstances, and some features are the same, as long as the environmental requirements are not too harsh, they can be shared.