Optimisation of the Corrosion Resistance and Surface Anti-Corrosion Treatment of CCS Grade B Shipbuilding Steel Plates

1. Corrosion Resistance of CCS B Shipbuilding Steel Plates

CCS B steel exhibits moderate corrosion resistance. Its low-carbon, low-alloy microstructure is unable to withstand prolonged immersion in high-salinity seawater. Without anti-corrosion measures, pitting corrosion will occur within 3–6 months in a nearshore marine environment. Impurities such as sulphur and phosphorus in the steel further accelerate the corrosion process; therefore, surface preparation is required prior to coating.

2. Standard Surface Preparation Process

The standard surface preparation process for CCS B shipbuilding steel plates includes sandblasting, rust removal, degreasing and surface cleaning:

2.1 Sandblasting for Rust Removal

Remove surface scale and rust, controlling surface roughness to 40–75 μm to enhance the adhesion of the anti-corrosion coating.

2.2 Degreasing

Removes oil residues left over from the manufacturing process to prevent coating delamination caused by oil film isolation.

3. Anti-corrosion Coating Scheme

3.1 Mainstream Coating System

Epoxy marine anti-corrosion primer + marine topcoat. The primer is used to isolate oxygen and moisture, whilst the topcoat resists salt spray and UV erosion.

3.2 Hull Bottom (Areas Subject to Long-Term Seawater Immersion)

The use of anti-fouling and anti-corrosion coatings is recommended to prevent the attachment of marine organisms.

3.3 Maintenance Requirements

Regular inspections and touch-ups should be carried out during service. The aged coating layer must be polished and renewed every 2–3 years to maintain consistent anti-corrosion performance.