Both
spiral steel pipes and steel coiled pipes belong to welded steel pipes, and the production processes of the two are very different.
Spiral steel pipe is a spiral seam steel pipe made of strip steel coil as raw material, often warmly extruded, and welded by the automatic double-wire double-sided submerged arc welding process. The length of the
spiral steel pipe is 12 meters, and the delivery is settled by the inspection ruler, and the specification is basically above 219mm.
The steel plate coil adopts the T-welding process, which can produce steel pipes with a diameter of more than 400 and a wall thickness of 8-100mm. Usually, no sizing is carried out, and weighing is generally used for delivery. The implementation standards for steel coil products are: GBT50205-2001, GBT3092-2001, etc. Coiled pipes are widely used in petroleum, chemical, natural gas transmission, piling, urban water supply, heating, gas supply, and other projects. The price of steel coiled pipes of the same type is higher than that of
spiral steel pipes, and steel coiled pipes are mainly used in non-model or thicker industries.
There is no limit to the service life of the
spiral steel pipe itself, and the service life is mainly related to the operating environment and production process. To prolong the service life of the
spiral steel pipe with a poor operating environment, the outer wall and inner diameter of the steel pipe are anti-corrosion. Anti-corrosion
spiral steel pipe refers to the steel pipe that has been processed by anti-corrosion technology, which can effectively prevent or slow down the corrosion phenomenon caused by chemical or electrochemical reactions during transportation and use. The anti-corrosion
spiral steel pipe can effectively prevent or slow down corrosion, prolong the service life of the steel pipe, and reduce the operating cost of the steel pipe.
The anti-corrosion layers of steel pipelines that are widely used in China include petroleum asphalt, PE jacket and PE foam jacket, epoxy coal tar pitch, coal tar enamel paint, epoxy powder and three-layer composite structure, epoxy coal tar pitch cold wrapping tape (PF type), rubber-plastic epoxy coal tar pitch cold-wound tape (RPC type), etc. Currently, the most widely used anti-corrosion methods for pipelines are three-layer PE composite structure, single-layer powder epoxy, PF-type cold-wrapped tape, RPC-type cold-wrapped tape, etc. wrap.
1. Petroleum asphalt has a wide range of raw materials and low prices. However, the working conditions are poor, the quality is difficult to guarantee, and the environmental pollution is serious.
2. Epoxy coal tar pitch is easy to operate, but the covering layer has a long curing time and is greatly affected by the environment. It is not suitable for field operations, and it is difficult to construct below 10 °C.
3. Epoxy powder is anti-corrosion, using the electrostatic spraying method, it is well sintered with the anti-corrosion pipe of the same material, and has strong adhesion, but epoxy powder has a poor waterproof (high water absorption rate, up to 0.83%), and is used for cathode Protection design brings certain difficulties. On-site equipment has high requirements, is difficult to operate, and the quality is not easy to control.
4. 3PE heat-shrinkable material, strong anti-corrosion sealing, high mechanical strength, strong waterproof, stable quality, convenient construction, good applicability, and no pollution to the environment. PE has low water absorption (less than 0.01%), high epoxy strength, low water absorption of PE, and good softness of hot melt adhesive, etc. It has high anti-corrosion reliability. The disadvantage is: that compared with the cost of other filling materials, costly.
5. The construction of PF type and RPC type cold-wound tape is simple and easy, and the matching three kinds of setting glues make PF type epoxy coal tar pitch cold-wound tape can be constructed in any environment, any season, and any temperature conditions.
6. The characteristics of cold-wound tape and 3PE heat-shrinkable tape are: suitable for main anti-corrosion layer pipelines of various materials, while other methods are suitable for main anti-corrosion layer pipelines of the same or close materials.
Secondly, with the development of some pipelines, some pipelines also need thermal insulation for anti-corrosion. Oil is a very complex mixture, and it is easy to corrode pipelines. Anti-corrosion is necessary, but oil product pipelines also need thermal insulation in the case of anti-corrosion. In the northeast and winter, Thermal expansion and cold contraction will freeze and crack the pipeline, affecting stable supply.
