Container House Sandblasting Process
The container house sandblasting process is a key technology that utilizes high-speed abrasive impact on the steel surface to thoroughly strip away oxide layers, rust, and old paint, revealing the metal's natural color. It provides a clean, rough substrate for subsequent coatings, significantly enhancing the anti-corrosion lifespan.
I. Core Functions of the Process
Cleaning and Surface Activation: High-speed abrasive喷射 (such as steel shot or quartz sand) impacts the steel, removing scale, rust, old paint, and oil, achieving industrial-grade cleanliness (SA2.5-SA3.0) and presenting a uniform metallic luster.
Enhancing Coating Adhesion: The sandblasted surface forms microscopic concave-convex structures with a roughness controlled between 40-75μm, providing 'mechanical anchors' for the coating. This ensures tight bonding between the primer (such as epoxy zinc-rich paint) and the substrate, preventing paint peeling or cracking.
Extending Anti-Corrosion Lifespan: Combining sandblasting with epoxy zinc-rich primer leverages zinc's sacrificial anode protection to provide cathodic protection for the steel, extending the anti-corrosion lifespan several times compared to traditional simple painting processes.
II. Key Process Parameters
Abrasive Selection: Commonly used abrasives include angular steel shot, copper ore sand, or emery, which must meet requirements for high density, toughness, and uniform particle size to ensure impact force and cleaning effectiveness.
Sandblasting Pressure: Typically between 0.6-0.8MPa; insufficient pressure results in inadequate cleanliness, while excessive pressure may damage the steel surface.
Surface Roughness: Controlled through abrasive particle size and spraying time, it must meet the Sa2.5 grade (near-white) requirements of ISO 8501-1, allowing only minimal spot shadows on the surface.
Cleanliness Control: After sandblasting, residual sand particles must be removed using high-pressure air or vacuum suction to prevent coating particle defects.
III. Process Flow and Equipment
Pre-treatment: Inspect the steel surface, removing oil, dust, and other impurities to ensure no visible contaminants remain.
Sandblasting Operation: Utilize a closed sandblasting room or mobile sandblasting machine, powered by compressed air, to spray abrasive onto the steel surface, focusing on easily corroded areas such as welds and edges.
Post-treatment: Complete primer spraying within 4 hours after sandblasting to prevent secondary rusting; if delayed, apply a temporary anti-rust protective solution.
Equipment Configuration: Includes a screw air compressor (providing power), air storage tank (stabilizing air pressure), pressure-type sandblasting machine (core equipment), and supporting components (such as oil-water separators and sandblasting hoses).
IV. Application Scenarios and Advantages
The container house sandblasting process is widely applied in renovation derusting and anti-corrosion coating pre-treatment, with advantages including:
- High Efficiency and Thoroughness: Cleaning efficiency can reach 40-60㎡/h, far exceeding manual grinding.
- Strong Adaptability: Capable of handling 1-20 cubic meter containers without site restrictions (such as outdoor steel structure tower crane derusting).
- Cost Optimization: By reasonably selecting abrasives and equipment, labor and consumable costs can be reduced, enhancing renovation economic benefits.
