Welded Steel Pipe

Welded steel pipe, also known as welded pipe, is made of steel plate or steel strip after being crimped and welded. The production process of welded steel pipe is simple, the production efficiency is high, the variety and specification are many, and the equipment investment is small, but the general strength is lower than that of seamless steel pipe. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the progress of welding and inspection technology, the weld quality has been continuously improved, and the variety and specification of welded steel pipes have been increasing, and the seamless steel pipes have been replaced in more and more fields. Welded steel pipe is divided into straight welded pipe and spiral welded pipe according to the form of weld.
The production process of longitudinally welded pipe is simple, with high production efficiency, low cost and rapid development. The strength of spiral welded pipe is generally higher than that of straight welded pipe. It can produce welded pipe with larger pipe diameter with narrow blank, and it can also produce welded pipe with different pipe diameter with blank of the same width. However, compared with the straight seam pipe with the same length, the weld length increases by 30~100%, and the production speed is lower. Therefore, the small-diameter welded pipes are mostly straight welded, while the large-diameter welded pipes are mostly spiral welded.
Welded steel pipe for low pressure fluid transmission (GB/T3091-2008) is also known as general welded pipe, commonly known as black pipe. It is a welded steel pipe used for conveying water, gas, air, oil, heating steam and other generally low pressure fluids and other purposes. The wall thickness of steel pipe is divided into ordinary steel pipe and thickened steel pipe; The form of nozzle end is divided into steel pipe without thread (plain pipe) and steel pipe with thread. In addition to being directly used for conveying fluid, welded steel pipes for low pressure fluid transportation are also used as raw pipes of galvanized welded steel pipes for low pressure fluid transportation.
1. Galvanized welded steel pipe (GB/T3091-2008) for low pressure fluid transmission is also called galvanized welded steel pipe, commonly known as white pipe. It is a hot-dip galvanized welded (furnace welding or electric welding) steel pipe used for conveying water, gas, air oil, heating steam, warm water and other generally low pressure fluids or other purposes. The wall thickness of steel pipe is divided into ordinary galvanized steel pipe and thickened galvanized steel pipe; Nozzle ends are divided into unthreaded galvanized steel pipes and threaded galvanized steel pipes. The specification of steel pipe is expressed in nominal diameter (mm), which is the approximate value of inner diameter. Traditionally, inches are commonly used, such as 1/2, 3/4, 1, 2, etc.
2 Ordinary carbon steel wire sleeve (YB/T5305-2006) is a steel pipe used to protect wires in industrial and civil buildings, installation of machinery and equipment and other electrical installation projects.
3. Longitudinal welded steel pipe (GB/T13793-2008) is a steel pipe with longitudinal parallel weld and steel pipe. It is used for general structures, usually divided into metric welded steel pipes, welded thin-walled pipes, etc.
4. Spiral submerged arc welded steel pipe for pressure fluid transportation (SY/T5037-2000) is a spiral welded steel pipe for pressure fluid transportation, which is made of hot-rolled steel strip coil as pipe blank, spirally formed at regular temperature, and welded by double-sided submerged arc welding method. The steel pipe has strong pressure bearing capacity and good welding performance. It is safe and reliable to use after various strict scientific inspections and tests. The steel pipe has large diameter, high transmission efficiency and can save investment in pipeline laying. The pipeline is mainly used for transporting oil and natural gas.
5. The spiral seam high-frequency welded steel pipe (SY/T5038-2000) for pressure fluid transportation is a spiral seam high-frequency welded steel pipe used for pressure fluid transportation, which is made of hot-rolled steel strip coil as the pipe blank, spirally formed at regular temperature and welded by high-frequency lap welding method. The steel pipe has strong bearing capacity and good plasticity, which is convenient for welding and processing; Through various strict and scientific inspections and tests, it is safe and reliable to use, with large diameter of steel pipe, high transmission efficiency, and can save investment in pipeline laying. It is mainly used for laying pipelines for transporting oil and natural gas.
7. The spiral seam high frequency welded steel pipe (SY/T5039-2000) for general low pressure fluid transmission is made of hot-rolled steel strip coil as the pipe blank, which is spirally formed at regular temperature. The spiral seam high frequency welded steel pipe for general low pressure fluid transmission is welded by high frequency lap welding method.
8. Spiral welded steel pipe for pile (SY/T5768-2000) is made of hot-rolled steel strip coil as pipe blank, spiral formed at regular temperature, and double-sided submerged arc welding or high-frequency welding, which is used for steel pipe for foundation pile of civil construction structure, wharf, bridge, etc.