How to judge the quality of steel shot

　　1. Moderate chemical composition. After years of production experience, we have summarized some rules. Chemical composition is an indicator of the basis of steel shot and steel grit. It will determine the microstructure of steel shot and steel grit and the effect of subsequent heat treatment. National standards for high carbon cast steel shots and cast steel sand stipulate: 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 tell you a little secretly, silicon and manganese can improve the strength and hardness of steel shots. They should be as high as possible (preferably no less than 0.7%). Sulfur and phosphorus are harmful elements that can easily make steel shots brittle and lead to premature rupture. It should be as low as possible (preferably<0.03%).

　　2. Appropriate hardness If the steel shot or steel sand is too soft, it will slow down the cleaning speed and reduce the work efficiency. During shot peening, steel shots that are too soft cannot produce suitable residual stress, and the force of low-hardness shots 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 projectile breakage, cause excessive consumption, and cause greater wear and tear on the equipment, which will increase equipment maintenance costs. Therefore, appropriate hardness is also critical. This is also One of the reasons why the crushing rate of non-standard steel shot and steel grit is relatively high.

　　3. Resist deformation and increase usage. The microstructure of steel shot (sand) can resist deformation, which can reduce energy loss and increase or decrease fatigue life when acting on the working surface. In addition, reducing brittle carbides during the production process can resist premature breakage of steel shot (sand) and increase usage.

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

　　5. Economical Materials Fatigue life is the ability of steel shot (sand) to resist breakage when it acts on the working surface. Abrasives with longer fatigue life will become economical abrasives. Steel shot will convert appropriate energy into cleaning. No matter which application field, the quality of steel shot and steel grit is the key to effective operation. Steel shot It can effectively transform energy during use and play a role in cleaning and strengthening.