Surface Treatment Methods of ERW Steel Pipes

 ERW steel pipe adopts the skin effect of high-frequency current to produce high temperature and external force extrusion at both ends of the steel plate in a short time. This is a true electrodeless metal butt. Using hot-rolled coils as raw materials, the wall thickness of ERW steel pipes can be controlled to about ±0.2mm. The end of the steel pipe adopts the American APL standard or GB/T9711.1 standard. The pipe end is cut and the conveying length is fixed. In recent years, in natural gas pipeline network projects and natural gas companies, ERW steel pipes have been widely used as the main steel pipes in urban pipeline networks. At present, ERW high-frequency straight seam steel pipe accounts for 60% of the world’s steel pipe usage.

With the development of the economy and energy industry, long-distance oil and gas pipelines are an important way to ensure energy. In the anti-corrosion construction process of oil and gas pipelines, the surface treatment of ERW steel pipes is one of the key factors that determine the anti-corrosion service life of the pipeline. It is the premise of whether the anti-corrosion coating can be firmly combined with the steel pipe. Layer type, coating quality and construction environment, the effect of surface treatment of straight seam steel pipe on the life of anti-corrosion coating is about 50%. Therefore, the surface treatment methods of steel pipes should be continuously explored and summarized in strict accordance with the requirements of the steel pipe surface anti-corrosion coating specifications.

1. The cleaning of ERW steel pipes uses solvents and emulsions to clean the steel surface to remove oil, grease, dust, lubricants and similar organic matter, but cannot remove oxide scale, rust on the steel surface, flux, etc., and can only be used as anti-corrosion production Auxiliary means.

2. If the steel surface is firmly attached to the iron oxide scale, its rust removal effect is not ideal, and it cannot meet the requirements of anti-corrosion construction for anchoring particle depth. ERW steel pipe rust removal tools mainly use wire brushes and other tools to polish the steel surface. Manual rust removal can reach SA2 level, and power tool rust removal can reach SA3 level, which can remove loose or raised oxide scale, rust, and welding slag etc..

3. The pickling of ERW steel pipes is generally treated by chemical and electrolytic methods, which can be used as reprocessing after sandblasting and rust removal. Although chemical cleaning can make the surface clean and rough to a certain degree, its anchoring particles are relatively shallow. It is easy to cause pollution to the environment. Pipeline anticorrosion can only be treated by chemical pickling, which can remove oxide scale, rust and old coatings.