Welded steel pipe, also called welded pipe, is a steel pipe made by welding a steel plate or strip after crimping. Welded steel pipe production process is simple, high production efficiency, variety specifications, equipment, less, but the general strength is lower than the seamless steel pipe. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technologies, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have been increasing, and they have been replaced in more and more fields. Steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes in the form of welds.
The straight seam welded pipe has a simple production process, high production efficiency, low cost, and rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe. A narrower blank can be used to produce a larger diameter pipe, and a blank having a different diameter can be produced from a blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld seam increases by 30 to 100%, and the production speed is low.
Therefore, the smaller diameter welded pipe mostly adopts the straight seam welding, and the large diameter welded pipe adopts the spiral welding.
1. Welded steel pipes for low-pressure fluid delivery (GB/T3092-1993) are also called general welded pipes, commonly known as black pipes. It is a welded steel pipe used for the transportation of water, gas, air, oil and heating steam, and other generally lower pressure fluids and other uses. The wall thickness of the steel pipe is divided into ordinary steel pipe and thick steel pipe; the pipe end is divided into non-threaded steel pipe (light pipe) and threaded steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), and the nominal diameter is the approximate value of the internal diameter. Commonly used in inches, such as 1 1/2 and so on. The welded steel pipe used for low-pressure fluid transportation is not only directly used for conveying fluids, but also used as a raw pipe for galvanized welded steel pipes for low-pressure fluid transportation.
2. Galvanized welded steel pipe for low pressure fluid delivery (GB/T3091-1993), also known as galvanized welded steel pipe, commonly known as white pipe. It is a hot-dip galvanized welded (furnace or welded) steel pipe for general low pressure fluids such as water, gas, air oil, heating steam, and warm water. The wall thickness of the steel pipe is divided into ordinary galvanized steel pipe and thick galvanized steel pipe; the pipe end is divided into non-threaded galvanized steel pipe and threaded galvanized steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), and the nominal diameter is the approximate value of the internal diameter. Commonly used in inches, such as 1 1/2 and so on.
3. Ordinary carbon steel wire bushings (GB3640-88) are steel tubes used to protect wires in electrical and industrial installations such as industrial and civil buildings and installation machinery and equipment.
4. Straight seam welded steel pipes (YB242-63) are longitudinally parallel steel pipes with welded seams. Usually divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe and so on.
5. Spiral seam submerged arc welded steel pipe for pressure fluid transport (SY5036-83) is a hot rolled steel strip used as tube blank, which is often temperature spirally molded, and welded by double sided submerged arc welding method for pressure fluid transport. Spiral seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. After various rigorous scientific tests and tests, it is safe and reliable to use. Large diameter steel pipe, high transmission efficiency, and can save investment in laying pipelines. Mainly used for the transportation of petroleum and natural gas pipelines.
6. Spiral seam high-frequency welded steel pipe for conveying fluids (SY5038-83) is a hot-rolled steel strip used as a tube blank, which is heated at regular temperature by spiral molding and welded by high-frequency lap welding method for pressurized fluid conveying. Spiral seam high frequency welded steel pipe. The steel pipe has strong pressure bearing capacity, good plasticity, and is easy to be welded and processed. After a variety of strict and scientific inspections and tests, it is safe and reliable to use, the diameter of the steel pipe is large, the transmission efficiency is high, and investment in laying pipelines can be saved. Mainly used for laying pipelines for transporting oil, natural gas, etc.
7. Spiral submerged arc welded steel pipe (SY5037-83) for low-pressure fluid delivery is a hot-rolled steel strip used as a tube blank, which is usually thermo-screwed and is made of double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes for general low pressure fluids such as water, gas, air and steam.
8. Spiral seam high-frequency welded steel pipe (SY5039-83) for general low-pressure fluid transmission is a hot-rolled steel strip used as a tube blank, which is usually temperature spirally molded, and welded by high-frequency lap welding method for general low-pressure fluid conveying spirals. Seam high frequency welded steel pipe.
9. Spiral welded steel pipe for piles (SY5040-83) is made of hot-rolled steel strips as tube blanks, and is usually thermo-screwed. It is made by double-sided submerged arc welding or high-frequency welding. It is used for civil construction structures, piers and bridges. And other basic pile steel pipe.