A useful foundry sand enquiry describes the casting process and the sand properties it needs. An AFS number is one part of that specification. Pair it with a sieve distribution, chemistry limits and supply condition to make quotations easier to compare.
What is AFS grain fineness number?
AFS grain fineness number (GFN) is calculated from a sieve analysis and summarises sand fineness. The American Foundry Society describes it as an estimate of the average sieve size of a sand sample. It is not a direct measurement in millimetres or a substitute for the full sieve results.
When your drawing or process sheet specifies an AFS range, share that range and any limits on individual sieve fractions. Avoid asking only for fine sand: different buyers can mean different distributions by the same description.
Start with your mould or core process
Tell the supplier whether the material will be used for green sand moulding, core making or another specified process. Include the binder system and any approved material specification. If you are replacing an existing sand, share its test report and the reason for the change.
A request for a base silica sand is different from a request for a finished resin-coated product. State which you need. Our foundry page describes the silica sand grade; confirm any further processing requirement with our team.
Agree what the test report must contain
Write down the required limits for silica, relevant impurities, moisture and grain distribution. Include the test methods your quality team uses so that results can be compared on the same basis. A typical product specification is a starting point for discussion, rather than a batch acceptance report.
The foundry product page lists indicative values, including an AFS range. Ask us to confirm the grade that can be supplied against your own specification and the analysis available for it.
- AFS GFN and the full sieve distribution
- Required SiO₂ and impurity limits
- Moisture and fines limits for the supply condition
- Sample identification and the agreed test methods
Plan a trial before changing production material
Agree sample requirements with your foundry team and supplier before a bulk purchase. Record the proposed sand grade, trial conditions and your acceptance criteria. Use your own process results to decide whether the material meets the requirement.
After approval, put the accepted specification, supply condition and documentation requirements into the purchase order. For repeat orders, reference that same specification so a familiar product name does not hide a change in requirements.
Explore the relevant grades
Request a silica sand quote with your specification, quantity and delivery location, or contact our team.