Welded steel pipes, also known as焊接管, are pipes made by pressing steel plates or strips. The production process of welded steel pipes is simple, with high efficiency, a wide variety of specifications, and low equipment investment. However, their overall strength is lower than that of seamless steel pipes. Since the 1930s, with the rapid development of high-quality continuous rolling lines for steel strips and advancements in welding and inspection technologies, the quality of welding lines has continuously improved, and so has the specification range of welded steel pipes.
Advantages of Spiral Seam Submerged Arc Welded Steel Pipe:
1. General low-pressure fluid transmission spiral seam submerged arc焊接钢管 (SY5037-2000) are manufactured from hot-rolled steel strip coils as pipe billets, formed by normal temperature spiral forming, and produced using double-sided automatic submerged arc welding or single-sided welding methods for submerged arc welding steel pipes used for the transmission of general low-pressure fluids such as water, gas, air, and steam.
2. General low-pressure fluid conveyance spiral seam high-frequency welded steel pipes (SY5039-83) are made from hot-rolled steel strip coils as pipe billets, formed into spirals at room temperature, and welded using high-frequency butt welding method for general low-pressure fluid conveyance spiral seam high-frequency welded steel pipes.
3. Pile spiral-welded steel pipes (SY5040-2000) are made from hot-rolled steel strip coils as billets, formed by normal temperature spiral rolling, and produced by double-sided submerged arc welding or high-frequency welding. They are used for steel pipes in civil engineering structures, wharfs, bridges, and other foundation piles.
4. Welded steel pipes for low-pressure fluid conveyance (GB/T3092-1993), also known as general-purpose welded pipes or black pipes, are used for conveying low-pressure fluids such as water, coal gas, air, oil, and heating steam, as well as for other applications. These pipes are categorized by wall thickness into standard and thick-walled pipes, and by end type into unthreaded (smooth) pipes and threaded pipes. The specifications of the pipes are indicated by nominal diameter (mm), which is an approximate value of the inner diameter. It is customary to express the nominal diameter in inches, such as 11/2. In addition to being used directly for conveying fluids, these low-pressure fluid conveyance welded steel pipes are also extensively used as the base pipes for galvanized welded steel pipes for low-pressure fluid conveyance.
5. Galvanized Welded Steel Pipes for Low-pressure Fluid Transmission (GB/T3091-1993), also known as galvanized electric welding pipes, commonly referred to as white pipes. These are used for conveying water, coal gas, air oil, heating steam, warm water, and other low-pressure fluids or for other purposes. The pipes are hot-dipped galvanized welded (either furnace welding or electric welding) pipes. The wall thickness of the pipes is divided into ordinary galvanized steel pipes and thickened galvanized steel pipes; the end types are threadless galvanized steel pipes and threaded galvanized steel pipes. The pipe specifications are indicated by nominal bore size (mm), which is an approximate value of the inner diameter. It is customary to express them in inches, such as 11/2.
6. Standard Carbon Steel Wire Conduit (GB3640-88) is a steel pipe used for protecting electrical wires in electrical installation projects for industrial and civil buildings, as well as in the installation of machinery and equipment.
7. Seamless Welded Steel Pipe (YB242-63) is a type of steel pipe where the weld is parallel to the longitudinal axis of the pipe. It is commonly categorized into metric welded steel pipes, thin-walled welded pipes, transformer cooling oil pipes, and so on.
8.螺旋缝埋弧焊钢管 (SY5036-83) for pressure fluid transmission is made from hot-rolled steel strip coils as billets, formed into spirals at room temperature, and welded using double-sided submerged arc welding. These pipes are used for the transmission of pressure fluids. The steel pipes have strong pressure-bearing capacity, excellent welding properties, and have passed various rigorous scientific inspections and tests, ensuring reliability. The large diameter pipes offer high transmission efficiency and can save on pipeline installation costs. They are mainly used for oil and gas pipeline transmission.
Welded steel pipes showcase their economic and aesthetic advantages in high-precision, low-pressure fluid applications. The production process for welded steel pipes is simple, with high efficiency, low costs, and rapid development. The strength of spiral-welded pipes is typically higher than that of straight-seam welded pipes. Larger diameter pipes can be produced from narrower billets, and pipes of different diameters can also be made from the same width billets. However, compared to straight pipes of the same length, the length of the weld seam increases by 30% to 100%, resulting in lower production rates. Therefore, smaller diameter pipes mostly use straight welding, while larger diameter welded steel pipes usually employ spiral welding.
Seamless steel pipe production technology is simple, with high efficiency, low cost, and rapid development. The strength of spiral-welded pipes is generally higher than that of seamless pipes, allowing for the production of larger diameter pipes with narrower billets and different diameter pipes with the same width billets. However, compared to pipes of the same length with a straight seam, the weld length increases by 30~ and the production speed is slower. Therefore, smaller diameter pipes mostly use straight seam welding, while larger diameter pipes usually employ spiral-welded pipes.
