Processing steps of epoxy powder coated steel pipe

First, the painting procedure of epoxy powder coated steel pipe: Manually remove oil stains, welding slag and burrs on the pipe wall → Sandblasting to remove rust Sa2.5 level/Ra60-100μm → Spray paint according to the requirements of the drawing → Quality inspection → Acceptance

Second, the construction process requirements of epoxy powder coated steel pipe painting: During painting construction, the ambient temperature should be 10-30℃, the relative humidity of the air should not be greater than 85%, the surface temperature of the coated base metal should be higher than the dew point by more than 3℃, and the base material temperature should not be painted when it is higher than 60℃.

Third, surface pretreatment of epoxy powder coated steel pipe:

(1) Surface pretreatment must be carried out before painting the steel surface. Before pretreatment, the welding slag, burrs, grease and other dirt on the steel surface should be cleaned. The surface treatment adopts mechanical shot blasting to remove rust, and the rust removal level reaches the Sa2.5 level requirement.

(2) After the steel pipe is derusted, it should be blown clean with dry compressed air or dust should be removed with a vacuum cleaner. If the steel pipe surface is found to be contaminated or rusted before painting, it should be reprocessed to the original derusting level. If the cleaned surface is accidentally touched by hand, the steel pipe surface should be cleaned immediately with solvent.

(3) The steel surface after rust removal should be painted as soon as possible, generally within 4 hours. On sunny days and good weather conditions, the longest time should not exceed 12 hours.

(4) Requirements for spraying paint coating

a) The painting operation should be carried out in a clean environment to prevent the undried coating from being contaminated by dust.

b) Before application, process tests should be carried out according to the regulations of the paint manufacturer.

c) The use of coating materials should be carried out according to the manufacturer's instructions. The type of coating material, number of layers, thickness, interval time, mixing method, etc. should be strictly followed.

d) Before mixing, components A and B should be fully stirred and evenly mixed, filtered through a 60-80 mesh sieve, and finally matured for 30 minutes before spraying.

e) For edges, corners, welds, cuts, and other parts, before painting, they should be manually painted one layer before large-scale painting to ensure the paint film thickness of the protruding parts.

f) When the temperature is above 30℃, in order to prevent the paint from curing too quickly, about 5% of special thinner can be added to dilute the paint.

g) When spraying primer and topcoat, the wet film thickness gauge should be used frequently to measure the wet film thickness of the paint and control the wet film thickness of each coat of paint.

h) The sprayed plastic-coated steel pipe should be carefully stored to protect the coating from damage and prevent the harmful effects of high temperature, scorching, and adverse climatic conditions.

i) A range of 200mm is reserved on both sides of the circumferential seam of each section of plastic-coated steel pipe. When painting the weld seam, it will not have an adverse effect on the quality of the weld seam. The inorganic zinc-rich workshop primer is 40-75μm to prevent the groove from rusting. After the on-site circumferential seam is welded, the weld area is derusted for the second time to meet the specified requirements, and then the paint is applied according to the design requirements to reach the specified thickness.