Epoxy powder anticorrosive steel pipe
In order to ensure the requirements of the buried environment and the special needs of the transport medium in the pipe, to improve the use effect and extend the service life of the buried pipe in different environments and different media, it is generally adopted to apply an anti-corrosion layer to the inner and outer walls of the steel pipe. At present, the steel pipe with three layers of PE anti-corrosion layer is the most widely used in steel pipe anti-corrosion. The steel pipe is coated with epoxy powder layer, wrapped with intermediate adhesive and outer polyethylene layer, which is an optimal steel pipe anti-corrosion layer.
The inner coating adopts liquid epoxy coating. Although it can initially meet the requirements of drag reduction and anti-corrosion of the medium in the tube, it is a room temperature curing coating, which has low chemical bond with the steel tube matrix. Under long-term operation, the coating is easy to be combined with the steel tube matrix. Falling off, causing defects in steel pipe operation. As an anti-corrosion coating with excellent performance, epoxy powder is excellent in combination with steel pipe matrix at high temperature and well leveled. It is the best coating for medium transportation in pipes. The 3PE coating and the epoxy powder coating inside the tube are the best combination coating for internal and external corrosion protection. The anti-corrosion tube has a good external anti-corrosion effect, which improves the anti-corrosion effect of the inner coating and prolongs the service life of the steel tube.Inner epoxy powder, outer layer 3LPE composite coating anti-corrosion pipe, steel pipe after degreasing, degreasing and water treatment, using the projectile steel shot processing technology to remove the outer wall corrosion of the pipe, etc., and remove the pipe by shot blasting or shot peening Wall rust, etc., then use medium frequency or other means to heat the steel pipe to 200 ~ 230 ° C, using air powder or electrostatic spraying technology to spray epoxy powder coating on the inner wall of the steel pipe, melt to form a thickness of 300μm epoxy powder coating, the steel pipe immediately Enter the three-layer PE molding structure, and use the curing time difference between the inner epoxy coating and the outer epoxy coating to fully level the inner powder, and then heat the steel tube to 180-220 ° C by intermediate frequency or other means to accelerate the solidification of the powder. The oxygen powder coating layer and the steel pipe are tightly combined under heating, which enhances the anti-corrosion and anti-resistance effect of the steel pipe. At the same time, under the heating state of the steel pipe, the epoxy powder coating is sprayed on the outer wall of the steel pipe by electrostatic spraying technology to melt and form an epoxy powder with a thickness of 110 μm. The coating, under the gelation of the epoxy powder coating layer, is formed by winding a 200 μm intermediate adhesive coating and 2.0 mm polyethylene coating. To form a dense protective shell.
Since the inner surface of the steel pipe is coated with epoxy powder and the outer surface is coated with three layers of PE coating, the molding process utilizes the difference in performance between the inner and outer epoxy coatings, and enhances the bonding force between the inner and outer epoxy coatings and the steel pipe matrix. Good anti-corrosion, enhanced internal drag reduction and anti-corrosion performance in the tube, its anti-corrosion and drag reduction performance is much higher than the outer three-layer PE coating and the inner liquid epoxy coating anti-corrosion steel pipe, prolonging the service life of the steel pipe. Under the premise of ensuring excellent corrosion resistance of the outer wall of the steel pipe, the scouring and anti-corrosion ability of the inner wall of the steel pipe is increased.