Low and medium chromium cast balls have poor wear resistance and high crushing rate. Although they are cheap, the overall cost performance is not high, so they are not recommended here. High chromium cast ball has excellent hardness and is a high-quality wear-resistant material. It has been widely used in dry ball mills in the cement industry. However, high chromium cast balls have poor toughness and are prone to breakage in ball mills with a diameter of more than 3 meters. The price is higher.
Influence of cast steel ball material: Generally speaking, the harder the steel ball, the greater the wear resistance. To improve the wear resistance of the steel ball, it is necessary to increase its hardness, but as the hardness increases, the impact toughness of the steel ball will decrease. At the same time, the hardness of the steel ball must also take into account the material and hardness of the liner, not too high (Damage the liner), it should not be too low (not wear-resistant). Therefore, how to balance the appropriate hardness and good impact toughness of steel balls is the key to improving the wear resistance of steel balls.
The commonly used materials for steel balls are: low carbon alloy, high manganese steel, high chromium cast iron, high carbon and high manganese alloy steel.
Low-carbon alloy steel balls have good toughness and low price. Under the same working conditions, their service life is more than double that of low-chromium cast balls;
High manganese steel has good toughness, good manufacturability and low price. Its main feature is that under the action of greater impact or contact stress, the surface layer will quickly produce work hardening, and its work hardening index is 5-7 times higher than other materials. The wear resistance has been greatly improved;
High chromium cast iron is a kind of wear-resistant material with excellent abrasion resistance, but its toughness is low, brittle and broken easily and expensive.
High-carbon and high-manganese alloy steel is mainly alloy structural steel containing chromium, molybdenum and other elements, with high hardness and good toughness. Its matrix structure has martensite, bainite or bainite + martensite composite structure. The hardness of the steel ball is about HRC60, and the impact toughness is ≥15J/CM2. Under the same working conditions, its service life is at least one time longer than that of the high manganese steel ball.