Applications
Desanding
Desanding is a heavy duty shot blasting operation in the foundry industry. Goal is to clean sand and other foundry contaminants on the castings, which can vary from watch cases to railcar wheels and marine engine blocks. The size and material of the casting guide the abrasive that is most effective. Normally the larger the casting the larger the shot size, but in most cases S460 and S390 are being used.
Steel grit GP is often used in this operation to increase the production output. This softest grit with a hardness between 42 and 52 HRC, is also referred to as angular shot, since it will get rounded during its lifetime.
In cases of aluminium based casting the cast steel shot may be replaced by stainless steel shot or aluminium shot and cut wire shot.
Descaling
Descaling is mainly conducted in the steel industry to remove the mill scale as a result from hot rolling. Shot blasting machines quickly process the pipes, sheets, coils, beams and even prefabricated structures to some extent. In the forging industry descaling refers to cleaning after forging.
Mainly our high carbon steel shots are used for purpose and the most commonly used size for this application is S390. In order to run an efficient operation it is critical to closely and constantly monitor the abrasive operating mix and we are happy to assist with that.
Surface preparation
The activity where the work piece is cleaned and etched prior to the application of the coating. Whether an old coating or rust is being removed or if the very first coating is being applied, it is critical to have the correct anchor profile on the work piece. If the peaks are to low this may lead to premature coating failure and if the peaks are too high too much of the expensive coating will be used or insufficient coverage. The values for average height between peak and valley (Rz) need to be monitored to successfully run the operation.
Shot peening
Shot peening is performed to increase the resistance to stress and improve the fatigue life of the product. By hammering the abrasive particles at the surface, the surface is being dimpled causing compression stresses under the dimple. As the media continues to strike the part, multiple overlapping dimples are formed at the work piece, which strengthens it. Shot peening is performed in the aircraft industry to ensure strength without having to add extra weight. In the automotive industry it is being used to strengthen parts that endure stress like springs, gears, torsion bars, stabilizers etc. Shot peening is a delicate process where the various parameters must be closely monitored:
- particle size
- particle quantity
- projection speed
- projection angle
- duration of the process
