There are several standards for high-quality steel grit. Firstly, the steel grit
can be used in the surface of workpiece, and can clean the surface effectively. Secondly, the steel grit should have a long endurance life and can reduce the consumption during application.
1. Chemical composition:
Chemical composition is the most fundamental indicator for steel girt which determines the microstructure and effect of heat treatment of steel grit. The content of carbon should be moderate. Silicon and manganese can improve the hardness and strength of steel grit, whose content can be as high as possible, normally at least 0.8%. Sulfur and phosphorus are harmful element which can make the steel girt frailer, therefore, the content should be as low as possible, generally no more than 0.03%.
If the steel grit is too soft, it will reduce the speed of clean and working efficiency. During peening, soft steel grit can not form the proper residual stress. If the hardness is too high, then will influence the surface and increase the chance of fragmentation and cause huge abrasion to equipment thus increase the maintenance cost. Therefore, the proper hardness is also crucial.
3. The microstructure:
The microstructure of steel grit should withstand deformation and when using on the surface it can reduce the loss and increase the endurance life. In addition, if there is too much brittle carbide in the microstructure, the steel grit will be easy to rupture and increase the amount of steel grit.
4. Physical defects:
Steel shot should reduce the physical defects which may cause rupture. Due to the manufacturing technique, there must be some physical defects in steel grit. It’s necessary to have corresponding control process during manufacturing, and reduce the proportion of defective particles.
5. The endurance life:
The endurance life is the resistance when using in the surface. The steel grit with the longest endurance life will be the most economical one, if it can convert the appropriate energy into the cleaning.
Whatever in which industry, steel girt is always the key factor for effective manufacturing, which determines the effective conversion and cleaning strength, also the processing cost.