NATIONAL STANDARD OF THE GRINDING BALLS IN CHINA(7)
7.1 The casting grinding ball shall be inspected by the supplier’s quality inspection department.
7.2 Chemical composition inspection shall be conducted in batches. If melt by induction furnace, each furnace as batch; if melt by cupola furnace, every 2hours as batch. Get one example to inspect the composition for each batch. If the test result is unqualified, then double sampling re-inspection, which still has 1 sample is unqualified, then the batch of grinding ball is unqualified.
7.3 The diameter and hardness of grinding balls are inspected in batches. The same-grade of the balls under the condition of stable melting process, melt by using the same melting furnace and the same heat treatment process (if heat treatment is needed), the certainquantity and the same size of grinding balls shall be called as the batc Three grinding balls were randomly selected from each batch for inspection. If one ball is unqualified, the same number of ball is randomly selected for re-inspection. The quantity of unqualified ball is more than or equal to 2. Then the batch of grinding ball is not qualified. If the hardness of the grinding ball is not qualified, repeated heat treatment is allowed.
8.Packing, marking and transportation
8.1 casting grinding balls can be packed by plastic bag, iron drum or in bulk.
8.2 If packing in bulk, should mark the grinding balls grade and size or the balls code in the certain place. During the packaging transportation, should mark the following information:
- The buyer’s name, address and the destination
- The casting grinding balls’grade, size or the special code
- Packaging number
- Gross and net weight
- Suppliers name and address
8.3 Each batch of balls shall be accompanied with the Product Certificate or Quality Certificate, which indicates:
1) The suppliers name and brand
2) Casting grinding balls grade, size or special code
3) Batch number
4) Inspection result
5) Standard Number
6) The manufacturing time