Characteristics and Heat Treatment Process of High Chrome Cast Balls

The grinding balls serve as the abrasive components in a ball mill. They produce a grinding and peeling effect to crush and grind materials through the collision and friction between the balls and the material. They are widely used in grinding industries such as iron ore and non-ferrous metal ore beneficiation plants, cement plants, thermal power plants, refractory material plants, steel plants, phosphate fertilizer plants, etc.

Introduction to High Chrome Cast Balls

Depending on the material, grinding balls can be classified into metal grinding balls and non-metal grinding balls. Metal grinding balls can further be divided into cast, forged, and rolled grinding balls based on their production methods. Among them, high chrome cast balls are widely applied due to the addition of a significant amount of chromium element. During the solidification process, they can form M₇C₃ type eutectic carbides with excellent wear resistance, offering significantly higher abrasion resistance capability and an advantageous price-performance ratio.

Characteristics of High Chrome Cast Balls

Generally, the as-cast microstructure of high chrome cast balls is relatively coarse and cannot meet usage requirements. Follow-up heat treatment processes are needed to achieve the desired microstructure. As the final process in the production of high chrome cast balls, heat treatment determines the realization of their mechanical properties and the distribution state of carbides, playing a crucial role in improving product performance.

Heat Treatment Process of High Chrome Cast Balls

The heat treatment process of high chrome cast balls typically involves quenching and tempering:

Quenching is the most widely used technique in heat treatment processes. Generally, the workpiece is heated to above the critical temperature, held for a certain period, and then cooled at a rate exceeding the critical cooling speed to obtain a primarily martensitic structure.

Tempering involves heating the quenched workpiece to an appropriate temperature, holding it for a period, and then cooling it slowly or quickly. It is used to reduce or eliminate the internal stresses in the quenched steel parts, adjust the mechanical properties, stabilize the structure, and improve the machinability.

The quenched workpiece should be tempered promptly; only through the combination of quenching and tempering can the desired mechanical properties be obtained.