The difference between thin-walled spiral steel pipe and thick-walled spiral steel pipe

The concept of thin-walled spiral steel pipe: the strip steel is fed into the welded pipe unit, and after multiple rollers rolling, the strip steel is gradually rolled up to form a round tube blank with an open gap. The pressing amount of the extrusion roller is adjusted to control the weld gap to 1~3mm, and the two ends of the weld are flush.

1. If the gap is too large, the proximity effect is reduced, the eddy current heat is insufficient, and the intercrystalline bonding of the weld is poor, resulting in infusion or cracking.

2. If the gap is too small, the proximity effect is increased, the welding heat is too high, causing the weld to burn; or the weld is extruded and rolled to form a deep pit, affecting the surface quality of the weld.

After the two edges of the tube blank are heated to the welding temperature, under the extrusion of the extrusion roller, a common metal grain is formed to penetrate and crystallize each other, and finally, a solid weld is formed. If the extrusion pressure of the spiral steel pipe is too small, the number of common crystals formed will be small, the strength of the weld metal will decrease, and cracks will occur after being stressed; if the extrusion pressure is too large, the molten metal will be squeezed out of the weld, which not only reduces the strength of the weld, but also produces a large number of internal and external burrs, and even causes defects such as welding overlap.

Uses of thin-walled spiral steel pipes: National standard spiral steel pipes are mainly used in tap water projects, the petrochemical industry, the chemical industry, the power industry, agricultural irrigation, and urban construction. They are one of the 20 key products developed in my country. For liquid transportation: water supply and drainage. For gas transportation: coal gas, steam, liquefied petroleum gas. For structural use: as piling pipes, bridges; docks, roads, building structure pipes, etc.

The concept of thick-walled spiral steel pipe: refers to a spiral steel pipe with a slightly thicker wall thickness than ordinary spiral steel pipes. Compared with ordinary thick-walled spiral steel pipes, the advantages are high compressive strength, high impact strength, high safety performance, and longer service life. The implementation standards are 5037, 9711, and API.

Thick-walled spiral steel pipe forming process:

1. Before spiral steel pipe forming: The spiral steel pipe adopts the advanced double-sided submerged arc welding manufacturing process, which can be welded in position, and it is not easy to have defects such as misalignment, welding deviation, incomplete penetration, and it is easy to control the welding quality and position. The spiral steel pipe adopts a special welding process, which can be welded in the welding position without any errors or defects, which can ensure the qualification of the spiral steel pipe and the quality is well guaranteed.

2. During the forming of the spiral steel pipe: During the forming process of the spiral steel pipe, the steel plate should be deformed evenly, with small residual stress and no scratches on the surface. Therefore, the steel plate for making the spiral steel pipe should be carefully selected, and the surface should be uniform and without scratches. The processed spiral steel pipe has greater flexibility in the size specification range of diameter and wall thickness, especially in the production of high-grade thick-walled pipes, especially small and medium-caliber thick-walled pipes, it has advantages that other processes cannot match, and can meet users' more requirements in terms of spiral steel pipe specifications. The diameter and size range of spiral steel pipes should be flexibly controlled. By taking advantage of their advantages and meeting the extensive needs of more users, spiral steel pipes can be popularized and promoted.

The development direction of thick-walled spiral steel pipes:

With the development of industry, higher requirements are put forward for the use of spiral steel pipes in engineering. The reason why thick-walled spiral steel pipes appear is that the pressure generated by some media that need to be transported is unbearable for ordinary spiral steel pipes. If they are replaced with straight-seam steel pipes or seamless steel pipes, the cost of the project will be greatly increased. If it is a dangerous medium, we will inevitably increase the cost. Therefore, when selecting pipelines, it is determined according to the medium that needs to be transported in the project and the pressure that the medium will generate.