How to judge the quality of cast iron grinding ball?

Every enterprise in production technology and production equipment, production personnel, the use of raw materials are distinct. So grinding balls on the quality of enterprises is also differ in thousands ways. So cast iron grinding balls for sale should know clearly when the choose and buy, in order to avoid buy inferior quality of the product, then to judge the quality of cast iron grinding ball.
1. Generally speaking, its surface rockwell hardness is much greater than 60 HRC.
2. It want to have a combination of high toughness.
3. Its surface is smooth, poured riser area of steel ball of the total surface area is small.
4. The supplier should be provided to the spectral analysis and a series of inspection reports, dare to a clear commitment in the contract.