Rust removal methods of LSAW steel pipe

In the anti-corrosion construction process for pipelines, the surface treatment of LSAW (Longitudinal Submerged Arc Welding) steel pipes is crucial for determining the longevity of the pipes. This surface treatment ensures a solid bond between the pipe and its anti-corrosion layer. Studies have shown that, aside from the type of coating, the quality of coating, and environmental factors during construction, the surface treatment of LSAW steel pipes accounts for approximately 50% of the coating’s lifespan. Therefore, adhering to stringent surface treatment standards is essential. The main methods for rust removal in LSAW steel pipes are as follows:

Solvent or Emulsion Cleaning:

Purpose: Removes oil, grease, dust, and similar contaminants.

Limitations: Cannot remove rust, oxides, or welding flux, so it serves as a supplementary process.

Pickling:

Methods: Chemical and electrolytic pickling.

Usage: Typically, chemical pickling is used in pipeline corrosion protection to remove oxides, rust, and old coatings. It is sometimes followed by sand-blasting.

Advantages: Achieves a certain level of cleanliness and roughness.

Disadvantages: Results in a light anchor pattern and may pollute the environment.

Mechanical Cleaning:

Tools: Wire brushes and other mechanical tools.

Effectiveness: Removes loose oxide, rust, and welding slag. Hand tools can achieve a Sa2 grade of rust removal, while power tools can achieve Sa3.

Limitations: Not effective on firmly attached oxide scales and does not achieve the required corrosion depth for anchor patterns.

Spray Rust Removal:

Process: Uses a high-power, high-speed rotating blade motor to spray abrasive materials (steel shot, grit, wire segments, minerals) onto the pipe surface.

Advantages:

Completely removes oxides, rust, and dirt.

Achieves uniform roughness.

Enhances physical adsorption and mechanical adhesion of the anti-corrosion layer.

Ideal Method: Jet rust removal is considered the ideal method for pipe corrosion protection, with shot peening used for internal surfaces and shot blasting for external surfaces.

Strict adherence to these rust removal techniques is necessary to prevent further damage to the LSAW steel pipes and ensure the anti-corrosion treatment is effective. This process not only improves the appearance of the pipes but also enhances their performance in the steel industry.