Steel pipes are easily eroded by oxidation, corrosion and other factors during use, so the anti-corrosion treatment of steel pipes after welding is very important. General anti-corrosion treatment methods include painting, covering, electroplating, etc., and in the anti-corrosion treatment of steel pipes after welding, the commonly used methods are cathodic protection and hot-dip galvanizing.
Cathodic protection is to use the electrochemical principle to form a protective electric field with a negative potential on the surface of the steel pipe, so that the surface of the steel pipe is not corroded. This method needs to coat a layer of special protective agent on the surface of the steel pipe, and provide current through an external power supply, so that a protective film is formed on the surface of the steel pipe.
Hot-dip galvanizing is to immerse the steel pipe in molten zinc, so that a layer of zinc layer is formed on the surface of the steel pipe, so as to achieve the purpose of anti-corrosion. This method requires that after the steel pipe is welded, the surface is cleaned and treated first, and then the steel pipe is immersed in molten zinc for hot-dip galvanizing treatment.
In short, the anti-corrosion treatment of steel pipes after welding is very important, and the purpose of anti-corrosion can be achieved by methods such as cathodic protection and hot-dip galvanizing.
The base material of anti-corrosion welded steel pipe includes straight seam steel pipe and spiral pipe.
Inner wall anti-corrosion coating: a film applied to the inner wall of the pipe to prevent corrosion inside the pipe, reduce frictional resistance, and increase throughput.
Commonly used coatings are amine cured epoxy resins and polyamide epoxy resins. Anti-corrosion and thermal insulation coating: on medium and small-diameter crude oil or fuel oil pipelines, in order to reduce the heat dissipation from the pipeline to the soil, a composite layer of thermal insulation and anti-corrosion is added to the outside of the pipeline. The commonly used insulation material is rigid polyurethane foam. If the outer protective pipe is a polyethylene pipe, there is no need to do anti-corrosion.
It is suitable for pipe networks such as underground water supply and drainage in coal mines, underground spraying, positive and negative pressure ventilation, gas drainage, and fire sprinkler. Thermal power plant process water waste slag and return water pipeline. It has excellent applicability for water supply pipelines of sprinkler and sprinkler systems. Electric power, communication, highway and other cable protection sleeves. Applicable to high-rise building water supply, heating network heating, water supply engineering, gas transmission, buried water transmission and other pipelines. Process pipelines for transporting corrosive media in petroleum pipelines, chemical, pharmaceutical, printing and dyeing industries. Sewage treatment discharge pipes, sewage pipes and bio-pool anti-corrosion projects. Agricultural irrigation pipes, deep well pipes, drainage pipes and other networks, etc.