The Difference Between Shot Blasting and Sandblasting

Shot blasting uses a high-speed rotating impeller to propel small steel or iron shot at high speed, impacting the surface of parts and removing the oxide layer. Simultaneously, the high-speed impact causes lattice distortion and deformation of the surface crystals, increasing surface hardness. It’s a method of cleaning parts and is commonly used for cleaning castings or strengthening surfaces.

Shot blasting is generally used for regular shapes, with several blasting heads operating simultaneously from all sides, resulting in high efficiency and low pollution.

In the shipbuilding and repair industry, shot blasting and sandblasting are widely used. However, both use compressed air. Of course, shot blasting doesn’t necessarily require a high-speed rotating impeller. In the shipbuilding and repair industry, shot blasting (using small steel shot) is generally used for steel plate pretreatment (rust removal before painting); sandblasting (using mineral sand in shipbuilding and repair) is mostly used on completed ships or sections to remove old paint and rust from steel plates for repainting. In the shipbuilding and repair industry, shot blasting and sandblasting are primarily used to increase the adhesion of paint on steel plates.

However, cleaning castings isn’t limited to shot blasting. For large parts, tumbling is typically performed first. This involves cutting off the riser of the casting and placing it in a tumbling drum. The parts collide with each other inside the drum, removing most of the surface sand before shot blasting or sandblasting.