From which aspects to judge the quality of steel shot

　　1. Moderate chemical composition With many years of production experience, we have summarized some rules. Chemical composition is an indicator of the basis of steel shot and steel grit, which will determine the microstructure of steel shot and steel grit and the effect of subsequent heat treatment. The national standard for high-carbon cast steel shot and cast steel grit stipulates: carbon (C) content: 0.85-1.20%; silicon (Si) content: ≥0.40%; manganese (Mn) content: 0.35-1.20%; sulfur (S) content: ≤0.05%; phosphorus (P) content: ≤0.05%. Let me say quietly that silicon and manganese can improve the strength and hardness of steel shot, and should be as high as possible (preferably not less than 0.7%). Sulfur and phosphorus are harmful elements, which can easily make steel shot brittle and cause premature rupture, and should be as low as possible (preferably<0.03%).

　　2. Appropriate hardness If the steel shot or steel grit is too soft, it will slow down the cleaning speed and reduce work efficiency. During shot peening, too soft steel shots cannot produce suitable residual stress, and the force of low-hardness shots cannot be compensated by increasing the impact time. Too high hardness will produce undesirable surface morphology, increase the probability of shot breakage, make consumption too high, and cause greater wear on equipment, which will increase equipment maintenance costs. Therefore, appropriate hardness is also critical, which is one of the reasons why the breakage rate of non-standard steel shots and steel sand is relatively high.

　　3. Resist deformation and increase usage The microstructure of steel shots (sand) can resist deformation. When acting on the working surface, it can reduce energy loss and increase or decrease fatigue life. In addition, reducing fragile carbides during the production process can resist premature rupture of steel shots (sand) and increase usage.

　　4. Fewer defective particles Steel shots (sand) must contain as few physical defects as possible that can cause abrasive breakage. Due to the production process used, steel shots (sand) will always have certain physical defects. There are corresponding processes in production to control and reduce the proportion of defective particles.

　　5. Economical materials Fatigue life is the ability of steel shots (sand) to resist breakage when acting on the working surface. Abrasives with longer fatigue life will become economical abrasives. If steel shot can convert appropriate energy into cleaning, the quality of steel shot and steel grit is the key to effective operation regardless of the application field. Steel shot can effectively convert energy during use and play a role in cleaning and strengthening.