What is high-frequency welded pipe? What are the differences with steel pipes?

1. Welded steel pipe for low-pressure fluid escort (GB/T3092-1993) is also called ordinary welded pipe, commonly known as black pipe. It is a welded steel pipe used for water, gas, air, oil, heating steam and other common low pressure fluids and other purposes. The wall thickness of steel pipe is divided into ordinary steel pipe and thickened steel pipe; The receiving end is divided into non threaded steel pipe (smooth pipe) and threaded steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), which is the approximate value of the inner diameter. Habits are often expressed in inches, such as 11/2. The welded steel pipe for low-pressure fluid escort is not only directly used for escorting fluid, but also widely used as the original pipe of galvanized welded steel pipe for low-pressure fluid escort.

2. Galvanized welded steel pipe (GB/T3091-1993) for low-pressure fluid escort is also called galvanized electric welded steel pipe, commonly known as white pipe. It is a hot-dip galvanized welded (furnace welding or electric welding) steel pipe used for water, gas, air oil, heating steam, warm water and other ordinary low pressure fluids or other purposes. The wall thickness of steel pipe is divided into ordinary galvanized steel pipe and thickened galvanized steel pipe; The receiving end is divided into galvanized steel pipe without thread and galvanized steel pipe with thread. The specification of the steel pipe is expressed by the nominal diameter (mm), which is the approximate value of the inner diameter. Habits are often expressed in inches, such as 11/2.

3. Ordinary carbon steel wire casing (GB3640-88) is a steel pipe used to maintain wires in industrial and civil buildings, installation of machinery and equipment and other electrical installation projects.

4. The straight seam electric welded steel pipe (YB242-63) is a steel pipe whose weld is longitudinally parallel to the steel pipe. It is generally divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe, etc.

The steel pipe is generally divided into two categories, one is called welded steel pipe, and the other is seamless steel pipe.

Welded steel pipe, also known as welded pipe, is a steel pipe made of rolled steel plate or strip steel. Welded steel pipe has simple consumption process, high consumption efficiency, many varieties and specifications, and less equipment, but its ordinary strength is lower than that of seamless steel pipe. Since the 1930s, with the rapid expansion of strip steel continuous rolling consumption and the progress of welding and inspection technology, the quality of welding seams has improved from time to time, and the variety and specification of welded steel pipes have increased day by day, and they have replaced seamless steel pipes in more and more areas. Welded steel pipes are divided into straight seam welded pipe and spiral welded pipe according to the way of weld.

The billet used for welding steel pipe is steel plate or strip steel, which can be divided into furnace welded pipe, electric welding (resistance welding) pipe and automatic arc welded pipe due to different welding processes. Due to the different welding methods, it can be divided into straight seam welded pipe and spiral welded pipe. Because of its end shape, it can be divided into circular welded pipe and special-shaped (square, flat, etc.) welded pipe. Welded pipes are divided into the following varieties due to their different materials and uses:

GB/T3091-1993 (galvanized welded steel pipe for low-pressure fluid escort). It is mainly used for escorting ordinary low pressure fluids such as water, gas, air, oil, heating hot water or steam, and pipes for other purposes. Its representative material is Q235 Grade A steel.

GB/T3092-1993 (galvanized welded steel pipe for low-pressure fluid escort). It is mainly used for escorting ordinary low pressure fluids such as water, gas, air, oil, heating hot water or steam, and pipes for other purposes. The representative material is Q235 Grade A steel.

GB/T14291-1992 (Welded steel pipe for mining fluid escort). It is mainly used for straight seam welded steel pipes for mine air pressure, drainage and axial gas drainage. Its representative materials are Q235A and B grade steel. GB/T14980-1994 (Large diameter electric welded steel pipe for low pressure fluid delivery). It is mainly used for water, sewage, gas, air, heating steam and other low-pressure fluids and other purposes. Its representative material is Q235 Grade A steel.

GB/T12770-1991 (Welded stainless steel pipes for mechanical structures). Mainly used for machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

GB/T12771-1991 (Stainless Steel Welded Steel Pipe for Fluid Escort). It is mainly used to escort low-pressure corrosive media. The representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.

The consumption process of longitudinal welded pipe is simple, the consumption 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 seam welded pipe. It can use a narrower billet to consume welded pipe with larger pipe diameter, and it can also use the same width of billet to consume welded pipe with different pipe diameter. However, compared with straight seam pipes of the same length, the weld length increases by 30%, and the consumption rate is low.

Therefore, the welded pipes with smaller diameters are mostly straight seam welded, while the welded pipes with larger diameters are mostly spiral welded. (For example, the pipeline of the West East Gas Pipeline is spiral welded pipe, and Taiyuan Heavy Industry consumes spiral welded pipe machine)

At present, there is a relatively new technology called "hot reducing", which is to roll the welded pipe again to improve its surface quality and dimensional tolerance, so that its comprehensive performance is close to that of seamless steel pipe.

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