What is the spiral steel pipe for drainage?

Posted by zora li on January 17th, 2024

What is the spiral steel pipe for drainage?

Drainage pipes generally use spiral steel pipes (SSAW pipes), and the welding method of spiral steel pipes is submerged arc welding. Because the welded steel pipe is spiral, the liquid pressure is distributed on each side of the steel pipe to increase the strength of the spiral steel pipe. If straight seam steel pipes (such as ERW pipes) are used, generally large steel pipes are coiled and welded with steel plates. The required steel plates are larger, which greatly increases the difficulty and cost of manufacturing.

In the production of spiral welded pipes, the stability of forming is closely related to the welding quality. Only by improving the forming quality can the welding quality be fully guaranteed. The size and change of the forming gap of spiral welded pipe during the welding process. In order to ensure that the spiral welded pipe welds have a good appearance and a certain penetration depth, the steel plate joint gaps are required to be uniform, and different welding specifications are adopted according to different weld gaps.

The production control of spiral welded pipes for drainage is to first improve the plasticity and toughness of the steel pipe, improve the cleanliness of the molten steel, reduce harmful inclusions, and improve the overall quality of the steel pipe. A reasonable cooling system is adopted during the production process to avoid internal cracks and improve the quality of steel pipes in many aspects. The heating temperature of spiral steel pipes is reasonably controlled during the production process, and the optimal heating temperature is selected by measuring the thermoplastic curve. When heating the tube blank, it is also necessary to pay attention to sufficient heat preservation time to reduce the deformation resistance and improve the plastic toughness of the thick-walled spiral tube.

Corrosion protection of spiral welded pipes for drainage
The anti-corrosion method of spiral welded pipes for drainage pipes also starts with inhibiting one of the processes. However, when the metal material with negative potential of the spiral welded pipe is connected to the spiral steel pipe, this protection rule does not occur. Therefore, anti-corrosion coating and sacrificial anode anti-corrosion methods should be used on the main gas pipeline in the city. For other non-main pipelines with lower pressure, anti-corrosion coating methods are generally used directly.
At present, the commonly used external anti-corrosion layer of buried gas pipelines has a three-layer PE composite structure. Powdered epoxy (FBE), coal tar enamel. Epoxy coal pitch, PE tape and other five categories. However, it should be noted that when the soil resistance is too high and the protected pipeline is flooded, sacrificial anode protection should not be used. Different anti-corrosion methods have different anti-corrosion quality and costs, which should be determined according to the pressure of the spiral welded pipe being protected.