High Hardness CADI Grinding Media Steel Balls For SAG Mill

1. Austempered ductile iron is a kind of material with high strength, plasticity, toughness and hardness. Because the materials used are mainly silicon and manganese, Its production cost is relatively low, and it is a kind of wear-resistant material with market competitiveness. Because of its excellent comprehensive mechanical properties, ADI  has been regarded as one of the important achievements in iron metallurgy in recent 30 years and has been widely used in various industrial sectors. For austenite + bainite matrix was the shell body of the ductile iron (ADI), the United States have research results in the 1950 s, but it was not until the 70 s application in the industry, our country in the 80 s by the tsinghua university professor de-hai wu research the shell body nodular cast iron and application in the industry, but because of the technology and equipment conditions not widely promoted.

2、Characteristics and advantages of  (ADI)

（1）High hardness and good wear resistance

Except the spheroidal graphite distributed uniformly in the microstructure of ADI steel ball, the matrix is the bainite + residual austenite containing a certain amount of carbide. The existence of residual austenite makes the grinding ball form a high hardening layer on the surface through impact and friction during use. With the constant wear of the grinding ball, the high hardness layer on its surface will be generated continuously and automatically, thus greatly improving the wear resistance of the grinding ball.

（2）  Hard outside and tough inside, not broken

While ADI steel ball has high hardness, its impact toughness is generally ak= 12-21j /cm2. According to the current national standard, the surface hardness of Chrome  grinding ball is HRC45~HRC58, but its impact toughness is only ak=2.5~3J/cm2. Although the impact value of forged grinding ball (ak=12J/cm2) is close to that of ADI ball, its surface hardness is HRC56~60 degrees, and its inner hardness is HRC40~56 degrees, but its price is high, its price is unstable, its material and material are mixed, and its service cost is relatively high. Therefore, the perfect combination of hardness and toughness makes ADI  steel ball truly reach the external hard and internal toughness, and reduces the direct and indirect economic loss caused by the crushing factor of grinding ball for users.

（3）   Regular appearance and increased production

The ADI steel ball produced by our factory is formed on the automatic production line of iron mould sand overlaying, and heat treatment is carried out through the computerized automatic heat treatment system. The production process of each stage is stable, which ensures that the shape of the grinding ball is regular (the same as that of the forging ball). In the process of using, these grinding balls always keep a good shape and do not lose roundness, so as to improve the production of the mill stand.

（4）  Light weight and obvious energy saving effect

Case Study  ---- China Gold Group

TESTΦ60 ADI CASTING GRINDING BALLS

6 months production data: ONE OF THE LARGEST COPPER AND MOLYBDENUM PLANTS     

* Grinding ball saving 519 tons * Fineness improved 2.26% * Electricity saving $55,000                   

                                                      TOTAL SAVINGS OVER $500,000                                                                                                                                                                                

 6 months production COPPER AND SILVER PLANT WearRate 22.8% and Electricity reduction 2.6%  

* Work-harden in the mill from 58 HRC up to 65HRC * High ductility absorbs high impact without cracking                                                                                                                        *      * Stay round and hard for the entire ball life * Lighter ball provides 5% more balls per ton * Increase ball life