The base material of
3pe anti-corrosion steel pipe includes seamless steel pipe, spiral steel pipe, and straight seam steel pipe. The three-layer polyethylene (3PE) anti-corrosion coating has been widely used in the oil pipeline industry due to its good corrosion resistance, water vapor resistance, and mechanical properties. The anti-corrosion layer of 3PE anti-corrosion steel pipe is very important to the life of buried pipelines. Some pipelines of the same material will not corrode after being buried underground for decades, and some will leak within a few years. It is because they use different outer anti-corrosion layers.
3pe anti-corrosion steel pipe anti-corrosion structure steel pipe outer wall anti-corrosion form
3PE anti-corrosion generally consists of 3 layers of structure:
The first layer of epoxy powder (FBE>100um)
The second layer of adhesive (AD) is 170～250um
The third layer of polyethylene (PE) 2.5 ~ 3.7mm
In actual operation, the three materials are mixed and integrated, and after processing, they are firmly combined with the steel pipe to form an excellent anti-corrosion layer. Its processing methods are generally divided into two types: winding type and round mold coating type.
3PE anti-corrosion steel pipe coating (three-layer polyethylene anti-corrosion coating) is a new anti-corrosion coating produced by cleverly combining the European 2PE anti-corrosion coating and the epoxy powder anti-corrosion steel coating (FBE) widely used in North America. Steel pipe coating. It has been recognized and used all over the world for more than ten years.
The coating of the 3PE anti-corrosion steel pipe is epoxy powder anti-corrosion coating that is in contact with the bottom layer and the steel pipe surface, and the middle layer is a copolymerized adhesive with branched functional groups. The surface layer is high-density polyethylene anti-corrosion coating.
3pe anti-corrosion coating combines the high impermeability and high mechanical properties of epoxy resin and polyethylene materials. So far, it is a pipeline anti-corrosion coating that has been recognized globally for its effectiveness and performance and has been applied in many projects.
The standard formulation of 3pe anti-corrosion steel pipe
In the initial stage of the introduction of 3PE coating technology, CNPC Engineering Technology Research Institute compiled China's first 3PE coating construction acceptance specification in April 1995 concerning DIN30670-1991 and NFA49-710 (March 1988 edition), which is used for Shaanxi-Beijing pipelines, Kushan pipeline construction. In the same year, it was upgraded to the industry standard SY/T4013-1995. After several years of engineering construction summary and practice, it was revised to SY/T0413-2002 in 2001 and implemented on August 1, 2002.
At the beginning of the standard formulation, according to the actual situation in China, polyethylene is mainly high-density polyethylene, and the Vicat softening point is set to be not less than 110°C; the thickness of the outer anti-corrosion layer is based on the German standard of low- and medium-density polyethylene. DIN30670-1991 to determine. The impact strength of the 3PE anti-corrosion coating has been dramatically improved, ensuring the construction quality of the Shanjing pipeline and the Kushan pipeline. According to the carbon black content of some unique materials, the mechanical strength and weather resistance of the 3PE anti-corrosion layer is guaranteed, and the peeling strength of the patch (that is, the peeling strength of the heat-shrinkable sleeve and heat-shrinkable tape to the primer steel) is increased. It has contributed to ensuring the quality of the external anti-corrosion coating of the pipeline.
Project application of 3pe anti-corrosion steel pipe
At present, 3PE anti-corrosion has successfully solved the problem of corrosion resistance and bump resistance of the outer wall of the steel pipe, but the inner wall anti-corrosion currently uses liquid epoxy coating IPN8710 in China. The liquid epoxy takes a long time to cure at room temperature, and the inner wall adopts liquid ring Oxygen coating can only reduce drag, but cannot achieve corrosion resistance and erosion resistance. If it is used in water pipelines, the inner wall must be in the form of heat-fused epoxy resin powder, which can better improve the corrosion resistance and corrosion resistance of the inner wall—friction capacity. Among them, the outer 3PE inner fusion-bonded epoxy composite steel pipe used in the Henan section of the middle line of the South-to-North Water Diversion Project was successfully applied to the South-to-North Water Transfer Project. It solves the characteristics that the inner wall is not easy to scale, smooth, wear-resistant, and corrosion-resistant.
