The hardness of austenitic cast balls can be controlled at HRC50-58, but during use, high carbon austenite transforms into martensite under external force, and the hardness can be increased to HRC60-63. During use, the surface of the cast balls undergoes layer by layer hardening, which is the most significant feature of CADI cast balls.

Energy saving of grinding machine: Due to the high carbon, high silicon, and high manganese content of austenitic ductile iron grinding balls, with a carbon equivalent Cp ≥ 4.4, the structure contains a large number of graphite balls with a density of 7.1-7.2g/cm3. The density of high chromium cast iron is 7.6-7.8g/cm3, and the density of austenitic cast balls is about 5-8% lighter than that of high chromium cast balls. Under the same filling rate conditions, the weight of grinding balls in the grinding machine needs to be reduced by 5-8%, and the starting and operating power of the ball mill is reduced, which can save more than 5-8% of energy.

The microstructure of austenitic ductile iron grinding balls contains spherical graphite, which has good shock absorption effect, reduces the noise of grinding machine operation, and improves environmental quality.

Austenitic ductile iron grinding balls do not break or lose their roundness during use. When ball milled from a diameter of 110 mm to a diameter of 30 mm, the surface remains spherical and the grinding effect is good. The output of the grinding machine can be increased by 10-20%.

The main raw materials used in the production of austenitic ductile iron grinding balls are silicon, manganese and other elements. Silicon manganese is a rich resource in China; However, high chromium cast balls require a large amount of chromium iron, which is a material that China needs to import in large quantities. The large amount of chromium iron used in grinding balls is not recyclable and reusable. Therefore, using high chromium cast balls in mining grinding is not in line with China's national conditions, while austenitic ductile iron grinding balls comply with China's resource policy.

With the development of mining and metal smelting industries, the wastewater, waste residue, tailings, and dust generated by mining, beneficiation, and smelting cause heavy metal pollution in the soil of industrial and mining areas and surrounding areas, resulting in cadmium, chromium, copper, nickel, lead, zinc, and cobalt content in the soil greatly exceeding the natural background values, causing ecological damage and serious deterioration of environmental quality. Soil pollution not only affects the yield and quality of crops, but also involves the quality of the atmosphere and water environment, and can endanger human health and life through the food chain. Moreover, the remediation of soil pollution takes decades or even hundreds of years. According to the previous sampling and monitoring of harmful heavy metals in 300000 hectares of basic farmland protection areas by the Ministry of Environmental Protection, 36000 hectares of soil exceeded the standard of heavy metals, with a rate of 12.1% exceeding the standard. Therefore, effective prevention and control of heavy metal pollution in soil is an important and urgent task in China's environmental protection work. In the crushing and grinding process of mineral processing, various chromium based wear-resistant materials are widely used. Under normal wear conditions, the particle size of the grinding balls and liners is below 5-10 µ m. For dry grinding in the cement industry, such debris enters the cement and becomes concrete without polluting the environment. However, for wet grinding in the mining industry, whether it is magnetic separation or flotation, the optimal particle size for mineral processing is generally 200-320 mesh, which is 48-76 µ m. Therefore, the debris of these chromium based wear-resistant materials cannot enter the concentrate powder, but is discharged with wastewater and infiltrates into the soil of the mining area. Over time, the chromium content in the soil accumulates, causing chromium pollution in the soil. How do these oxidized chromium or carbide chromium transform in the soil? How harmful is it? This requires research by the environmental protection department. I believe that as researchers, producers, and users of wear-resistant materials, we should all be responsible for our future generations, leaving a clean land for them. In wet grinding of mines, we should try to minimize or avoid using chromium based wear-resistant materials, and instead use austenitic ductile iron wear-resistant materials with less environmental impact. Austenitic ductile iron mainly contains three elements: carbon, silicon, and manganese, which are commonly present in the soil of the earth and do not pollute the soil.

Austenitic nodular cast iron grinding balls have better cost-effectiveness than high chromium cast balls. The comprehensive economic effect is obvious when used in wet grinding in mines, which is reflected in the following aspects: cost per ton of mining balls+energy-saving of grinding machines+improvement of production efficiency+reduction of daily ball loading workload. These comprehensive calculations show that there is great room for reduction in the cost per ton of grinding.