Shot blasting is more suitable for rust removal on ship decks due to its high efficiency, strong automation, and good environmental friendliness; Sandblasting is commonly used for the removal of old paint and rust layers in localized areas of formed ships. In terms of cleaning effect, the shot blasting surface is more uniform and can strengthen the metal, with high flexibility but high dust pollution.
For large and structurally regular metal surface treatments such as ship decks, shot blasting is the preferred solution. It uses a high-speed rotating impeller to centrifugally eject steel pellets (such as cast steel pellets and stainless steel pellets) onto the deck surface, relying on kinetic energy impact to remove oxide scale, salt, and rust. This method has a fast processing speed, for example, for processing 10 ㎡ steel plates, shot blasting only takes 15 minutes, while sandblasting takes 45 minutes, making it very suitable for batch operations in shipyards or pre-processing workshops.
In contrast, sandblasting rust removal relies on compressed air to blow abrasives (such as quartz sand and brown corundum) at high speed onto the surface of the workpiece. Although it can effectively remove rust, it is mostly used for segmented maintenance of formed ships, removal of old paint, or local treatment of complex areas. Due to the fact that abrasives are mostly disposable, costly, and prone to generating large amounts of dust, dust removal equipment is required.
The core differences between the two processes are as follows:
Cleaning effect and surface quality
The surface roughness Ra value after shot blasting treatment is usually controlled between 3.2-6.3 μ m, and the surface is uniform and forms a compressive stress layer, which helps to improve the adhesion and fatigue resistance of the coating. Sandblasting can achieve a wider range of Ra (0.5-50 μ m), suitable for customized textures, but the surface has honeycomb like pits, and the bonding strength for subsequent coating is slightly lower than that of shot blasting.
Applicable scenarios and workpiece types
Shot blasting is suitable for thick plates and large structural components such as decks and ship sections, and can efficiently complete the pre-treatment of the entire area; Sandblasting is more suitable for thin-walled parts, welds, or complex shaped areas to avoid deformation caused by excessive impact.
Environmental Protection and Operating Costs
The shot blasting system is designed with a closed cycle, and the steel shot can be recycled and used 5-15 times with less dust, which meets environmental protection requirements; Most sandblasting abrasives are non recyclable and cause serious dust pollution, requiring additional investment in environmental protection facilities.
