DNV DH32 Marine Steel Plate Processing Techniques: Cutting, Bending, Surface Treatment, and Anti-Corrosion Coating

1. Precision Cutting Process

Select the cutting method based on plate thickness:

Thin plates (4 - 20 mm): Use plasma precision cutting to ensure smooth, burr-free cuts and maintain assembly accuracy;

Medium- and thick plates (20 - 200 mm): Use oxy-fuel cutting for consistent cut quality and high efficiency.

After cutting, the cut edges should be ground to remove oxide layers and microcracks, thereby preventing stress concentration during subsequent welding and in-service operation.

2. Cold and Hot Bending Processes

DNV Grade DH32 marine steel plates possess excellent plasticity and bendability:

Small-angle bending: Use a room-temperature cold bending process, controlling the bending speed to prevent surface cracking;

Large-angle bending and thick-plate bending: Use a hot-bending process, controlling the heating temperature between 700 and 800 °C, followed by uniform, gradual cooling after bending to eliminate residual stresses and ensure stable plate shape and mechanical properties.

3. Surface Polishing and Finishing

After processing, the steel plate surface should undergo shot blasting to remove mill scale, cutting slag, and rust spots, ensuring the surface roughness meets the standards for applying marine anti-corrosion coatings.

Deformed steel plates should be straightened to ensure flatness complies with shipbuilding installation requirements, thereby avoiding excessive assembly gaps and additional structural stresses.

4. Marine Anti-Corrosion Coating Treatment

To withstand the highly corrosive marine environment, DNV Grade DH32 marine steel plates require professional anti-corrosion coating:

After surface preparation, marine-grade primer, intermediate coat, and topcoat are applied in layers according to process requirements to ensure uniform and continuous coating thickness;

For critical structures such as hull outer plates and offshore platforms, a heavy-duty anti-corrosion coating system is used to enhance resistance to seawater corrosion and extend the service life of the structure.