Standards for distinguishing the quality of steel sand

　　Steel sand is often used for metal surface treatment. Products treated with steel sand can meet national standards. At present, steel sand is the most advanced and ideal high-quality material for cleaning, blasting, rust removal and strengthening at home and abroad. High-quality steel sand products have moderate hardness, strong toughness, and impact resistance. They can be used repeatedly for several consecutive times. At the same time, they also have many characteristics such as long life, good rebound, strong adhesion, fast cleaning speed, low sand consumption, no breakage, high brightness of cleaned workpieces, and good technical effects. Of course, this is the advantage of high-quality steel sand. The treatment effect of inferior steel sand is greatly discounted. So how to test the quality of steel sand?

　　1. Hardness. If the steel sand is too soft, it will slow down the cleaning speed and reduce work efficiency. During sandblasting, too soft steel sand cannot produce suitable residual stress, and the force of low-hardness sand cannot be compensated by increasing the impact time. Too high hardness will produce undesirable surface morphology, increase the probability of sand breakage, make consumption too high, and cause greater wear on equipment, increasing equipment maintenance costs, so appropriate hardness is also critical.

　　2. Metallographic structure. The microstructure of steel grit must be able to resist deformation, and when acting on the working surface, reduce energy loss and increase or decrease fatigue life. Tempered martensite is the most fatigue-resistant. In addition, the microstructure must reduce brittle carbides, otherwise it will cause premature rupture of steel grit and increase the amount of use.

　　3. Chemical composition. Determines the microstructure of steel grit and the effect of subsequent heat treatment. The carbon content should be moderate. Silicon and manganese can improve the strength and hardness of steel grit, so it should be as high as possible. Sulfur and phosphorus are harmful elements that can easily make steel grit brittle and cause premature rupture, so they should be as low as possible.

　　4. Fatigue life. Fatigue life is the ability of steel shot sand to resist crushing when it acts on the working surface. The abrasive with the longest fatigue life will become the most economical abrasive if it can convert appropriate energy into cleaning.

　　5. Physical defects. Steel grit must contain as few physical defects as possible that can cause abrasive rupture. Due to the production process used, steel grit will always have certain such physical defects. There must be corresponding process controls in production to reduce the proportion of defective particles.