How to choose steel pipe?

Steel pipes are a very important building material, whether it is transporting fluids and powdered solids, exchanging heat, making mechanical parts and containers, manufacturing building structures, pillars and mechanical supports, or seeing home furniture. Steel pipes of various materials. What are the types of steel pipes? What is the size of the steel pipe? Let's take a look at the knowledge of enrollment in steel pipes.

1 Introduction of steel pipe

Steel pipe is a very important building material in life, and it is favored for its unique product characteristics and aesthetics. Steel pipe is an economical steel. The steel grades and specifications of the products are extremely diverse, and the performance requirements are various. Steel pipes can be used as conveying fluids and powdered solids, exchanging thermal energy, manufacturing mechanical parts and containers. The use of steel pipes to manufacture building structure grids, pillars and mechanical supports can reduce weight, save 20-40% of metal, and realize mechanized construction. The use of steel pipes to manufacture highway bridges not only saves steel and simplifies construction, but also greatly reduces the area of the protective coating and saves investment and maintenance costs.

2 Types and uses of steel pipes

According to production method
It can be divided into seamless steel pipe and seamed steel pipe, and the seamed steel pipe is simply referred to as straight seam steel pipe. Seamless steel pipes can be used in liquid pressure pipes and gas pipes in various industries. Welded pipes can be used for water pipes, gas pipes, heating pipes, electrical pipes, etc.
According to the purpose of steel pipe

1. Pipes for pipelines. Such as: water, gas pipe, steam pipe seamless pipe, oil pipeline, oil and gas trunk line pipe. Agricultural irrigation faucets with pipes and sprinkler pipes.
2. Tubes for thermal equipment. Such as general boiler boiling water pipe, superheated steam pipe, locomotive boiler superheat pipe, large pipe, small pipe, arch brick pipe and high temperature and high pressure boiler pipe.
3. Pipes for machinery industry. Such as aviation structural tubes (round tubes, elliptical tubes, flat elliptical tubes), automotive semi-axle tubes, axle tubes, automobile tractor structural tubes, oil cooler tubes for tractors, square and rectangular tubes for agricultural machinery, tubes for transformers, and bearings Tube and so on.
4. Pipes for oil geological drilling. Such as: oil drilling pipe, oil drill pipe (square drill pipe and hexagonal drill pipe), drill pipe, petroleum oil pipe, oil casing and various pipe joints, geological drilling pipe (core pipe, casing, active drill pipe, drilled , by hoop and pin joints, etc.).
5. Tubes for the chemical industry. Such as: petroleum cracking tubes, chemical equipment heat exchangers and pipelines, stainless acid-resistant tubes, high-pressure tubes for fertilizers, and pipes for transporting chemical media.
6. Other departments use the tube. Such as: container tube (high pressure gas cylinder tube and general container tube), instrumentation instrument tube, watch case tube, injection needle and its medical device tube.

According to the material of the steel pipe
Steel pipes can be divided into: carbon pipes and alloy pipes, stainless steel pipes, etc. according to the pipe material (ie steel type). Carbon pipes can be divided into ordinary carbon steel pipes and high-quality carbon structural pipes. Alloy tubes can be further divided into: low alloy tubes, alloy structure tubes, high alloy tubes, high strength tubes. Bearing tubes, heat-resistant and acid-resistant stainless steel tubes, precision alloys (such as Kovar) tubes, and high-temperature alloy tubes.

3 Specifications of steel pipes

Divide 1 inch into 8 equal parts, 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8 inches.
This is equivalent to the usual one-to-one to seven-point pipe. The smaller size is expressed in 1/16, 1/32, 1/64, and the unit is still inches. If the denominator and the molecule can be divided (eg, the molecules are 2, 4, 8, 16, 32), they should be approximated.
The inch is indicated by two cymbals in the upper right corner, such as 1/2". For example, the water pipe of DN25 (25mm, the same below) is the British 1" water pipe, and it is also the 8-point water pipe before liberation. The DN15 water pipe is an inch 1/2" water pipe, and it is also a 4-point water pipe before liberation. For example, the DN20 water pipe is an inch 3/4" water pipe, and it is also a 6-point water pipe before liberation. First, size: DN15 (4 points), DN20 (6 points), DN25 (1 inch tube), DN32 (1 inch 2 tubes), DN40 (1 inch half tube), DN50 (2 inch tube), DN65 (2 inch) Half pipe), DN80 (3 inch pipe), DN100 (4 inch pipe), DN125 (5 inch pipe), DN150 (6 inch pipe), DN200 (8 inch pipe), DN250 (10 inch pipe), etc.

4 Purchase steel pipe

1. The color is selected to be uniform and uniform, the inner and outer walls are smooth and flat, and there are no bubbles, depressions or impurities, which affect the surface performance defects.
2. It depends on whether the label on the product is complete. The name or trademark of the manufacturer, the date of manufacture, the name of the product, the size of the specification, the implementation of the standard number, etc. on the steel pipe, the product name, the nominal outer diameter, the pipe series S, etc. The handwriting should be clear and the check mark should match the actual.
3. Should buy the same brand of pipe and pipe fittings, because the raw materials of different brands may not be the same, the pipe fittings will have adverse factors, long-term use will cause leakage at the weld.
4. Good steel pipe quality is not high, not broken, so can not judge whether the quality of steel pipe can be broken. Since the impact resistance of the steel pipe is better than that of the real steel pipe, the steel pipe is more likely to be smashed, and the steel pipe is often broken.

5 Maintenance of steel pipes

1. Clean water
The clean water is washed with clean water to clean the inner wall of the steel pipe, but the impurities such as calcium and magnesium ionic scales and biological slime adhering to the inner wall of the steel pipe cannot be completely removed, and the effect is not obvious.
2. Syrup cleaning
The syrup cleaning is to add chemical reagents to the water, but the chemical composition is corrosive to the steel pipe, and also shortens the life of the steel pipe, which is a practice of simmering and fishing, and is not desirable.
3. Physical cleaning
Nowadays, the working principle of this kind of cleaning is basically based on compressed air. The launcher uses a launcher to fire a special projectile larger than the inner diameter of the pipeline to move it along the inner wall of the pipeline at a high speed and fully rub it. Clean the inner wall of the pipe. This method has obvious cleaning effect and basically no harm to the pipeline. It is the most thorough cleaning method to date.
Source: China Steel Pipeline Manufacturer - Yaang Pipe Industry Co., Limited (www.yaang.com)

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