Spraying process for 3PE fully powdered coating on steel pipe

Abstract

The invention discloses a spraying process for a 3PE fully powdered coating on a steel pipe. Equipment adopted by the spraying process includes a steel pipe conveying roller, an intermediate frequencyheating device, an epoxy powder electrostatic spraying device, an adhesive powder electrostatic spraying device, a polyethylene powder electrostatic spraying device and a water cooling device. Sprayguns of the three electrostatic spraying devices are arranged adjacent to one another so as to ensure that the adhesive powder melts to form an adhesive layer before the epoxy powder solidifies, and the polyethylene powder melts to form a polyethylene layer before the adhesive layer solidifies. The epoxy powder layer, adhesive layer and polyethylene layer are all coated by powder electrostatic spraying, the pipe body does not need to be heated again, only the steel pipe needs to be heated before spraying, and the epoxy powder layer, adhesive layer and polyethylene layer are cured by the wasteheat of the steel pipe, so that the process is simple and power resources are saved.

Description

Technical field: [0001] The invention belongs to the technical field of steel pipe anticorrosion layer composite structure forming, and in particular relates to a spraying process of a steel pipe 3PE full powder coating. Background technique: [0002] Pipelines are the safest and most economical way to transport oil, gas, water and other fluid media. However, the corrosion of pipelines is the most critical factor affecting the reliability and service life of pipelines. Pipeline anti-corrosion coatings mainly used petroleum asphalt anti-corrosion coatings in the 1950s and 1970s. Since the 1970s, anti-corrosion materials such as epoxy coal tar pitch coatings, polyethylene adhesive tapes, and coal tar enamel paints have been researched and applied successively. , developed and applied anti-corrosion materials such as 2PE polyethylene anti-corrosion layer, single epoxy powder (FBE) and a new generation of coal tar enamel. [0003] Three-layer structure polyethylene (3PE) anti-c...

AI Technical Summary

Problems solved by technology

However, there are currently the following disadvantages: (1) For welded steel pipes, because the second and third layers of the coating are extruded and wound, the coating will be thinned at the weld of the pipe body and the coating at the root of the weld will appear. voids and other defects; (2) 3PE coating is formed by extrusion, and the adhesive layer in the middle fails under low temperature and long-term service conditions, which makes the layering of the coating fail

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