Surface Pretreatment of Steel Pipes
Date:2026-08-07View:10Tags:A53 steel pipe,Welded steel pipe,Pipe fitting
There are four main methods for surface pretreatment of steel pipes:
Cleaning: Using solvents or emulsifiers to remove grease and dust from the steel pipe surface. This method can only handle organic contaminants and cannot remove rust or oxide scale, so it is usually only used as an auxiliary process.
Tool Rust Removal: Using tools such as wire brushes and grinding wheels for physical grinding, loose oxide scale, rust, and welding slag can be removed. Hand tools can achieve Sa2 grade, and power tools can achieve Sa3 grade, but it is difficult to handle firmly attached oxide scale and cannot achieve an ideal surface roughness.
Acid Pickling: Using chemical solutions such as hydrochloric acid and sulfuric acid to chemically react with rust and oxide scale, dissolving and removing them. This method has a high degree of cleanliness, but it generates waste liquid pollution and creates shallow surface texture. For steel pipes with special requirements for acid resistance, acid pickling is an important process.
Shot Blasting: Using high-pressure airflow or centrifugal force, abrasive materials such as steel shot or steel grit are sprayed at high speed onto the surface of the steel pipe, using violent impact to remove all contaminants and create a uniform roughness. This is the ideal rust removal method in pipeline corrosion protection, offering high efficiency and quality. It typically requires a near-white (Sa2.5) standard, with anchor pattern depth controlled between 40 and 100 micrometers to maximize the adhesion of the anti-corrosion coating. Shot blasting (or sandblasting) is mostly used for the inner walls of pipelines, while shot blasting (or sandblasting) is primarily used for the outer walls.
For high-quality anti-corrosion coatings, standard processes usually require shot blasting (or sandblasting) to remove rust, treating the steel pipe surface to Sa2.5 level before proceeding with the next coating step.
