Factors affecting steel grit quality

　　1. Hardness (GP-HRC42-50, GL-HRC56-60, GH-HRC63-66)

　　The hardness of the steel grit should be moderate. If the steel grit is too soft, it will slow down the cleaning speed and reduce work efficiency. During sandblasting strengthening, steel sand that is too soft cannot produce suitable residual stress, and the force of low-hardness sand cannot be compensated by increasing the impact time. If the hardness is too high, it will produce an unsatisfactory surface morphology, increase the probability of sand breakage, cause excessive consumption, cause greater wear and tear on the equipment, and increase equipment maintenance costs. Therefore, appropriate hardness is very important.

　　2. Chemical composition

　　The chemical composition will affect the hardness of steel shot, etc. The carbon (C) content should be moderate. Silicon (Si) and manganese (Mn) can improve the strength and hardness of steel grit, so they should be as high as possible. Sulfur (S) and phosphorus (P) are harmful elements that can easily make steel grit brittle and lead to premature rupture. They should be as low as possible.

　　3. Microstructure

　　The microstructure of steel grit can resist deformation and reduce energy loss and increase fatigue life when acting on the working surface. Tempered martensite is more fatigue-resistant. In addition, brittle carbides need to be reduced in the microstructure, otherwise it will cause premature rupture of steel grit and increase consumption.

　　4. Fatigue life

　　Fatigue life is the ability of steel grit to resist breakage when applied to a work surface. An abrasive with a longer fatigue life will become an economical abrasive if it can convert appropriate energy into cleaning.

　　5. Physical defects

　　Due to the production process used, steel grit will always have certain physical defects. Corresponding processes must be controlled during production to reduce the proportion of defective particles.