GRINDING MEDIA KNOWLEDGE
How to Read a Grinding Ball Inspection Certificate
A buyer’s guide to chemistry, hardness, dimensions, impact results and batch traceability.
Confirm the certificate matches the shipment
Check the purchase order, product size, steel grade, heat or batch number, quantity and production date. The same batch identity should appear on packaging labels and sampling records. A certificate without traceability cannot prove that its results belong to the delivered balls.
Read chemistry as a system
Carbon, chromium, manganese, silicon and other alloy elements work together with heat treatment. Compare the reported values with the agreed specification and test method; do not judge performance from chromium alone. Ask which laboratory performed the analysis and whether results are heat-level or sample-level.
Check hardness and dimensions
The report should distinguish surface and core hardness, identify the scale such as HRC, state sample locations and show individual readings rather than only an average. Diameter, ovality and surface defects should be recorded against the agreed sampling plan and tolerance.
Link test data to acceptance
Impact toughness, drop testing and broken-ball limits must use agreed methods and acceptance criteria. Buyers should retain the certificate, photos, sample list and nonconformance process. When comparing suppliers, review consistency across several batches, not a single ideal certificate.