Castings for pump makers, valve makers and automotive buyers all need a stated material grade, a tolerance on key dimensions and a test plan. What differs is the main risk: leakage for pumps and valves, fatigue and consistency for automotive.
Write the specification around that risk, then ask the foundry to show how it controls it.
Castings for pump makers
Pump casings, impellers and covers are mostly grey iron, SG iron or stainless steel. The main concerns are wall thickness, a clean internal waterway, balance of the impeller and porosity that could leak under pressure.
Impeller castings in particular should be checked for balance and for vane thickness, because small differences change flow and efficiency across a batch.
Ask for the material grade, chemistry and mechanical properties on a certificate, and a drawing with machining allowances. Impeller castings need a surface finish and dimensional control that keeps the pump efficient. Our overview of grey iron, SG iron and steel castings explains which to use.
Castings for valve makers
Valve bodies and bonnets hold pressure, so leakage and soundness matter most. Specify the alloy, the pressure class and the standard the valve will be tested to. Most buyers require a hydrostatic test on finished valves, and a radiographic or ultrasonic check on critical castings.
A porous casting can pass a visual check and still weep under test. See how hydrostatic pressure tests for valves are run and what they prove, and ask for the foundry's own defect records.
Also agree how castings are marked. A heat number on every body lets you trace a failure back to one pour and one set of test results, and it makes any claim far easier to settle.
Castings for automotive buyers
Automotive parts such as brake components, housings and brackets are made in volume, so consistency is the priority. Ask for process control records, statistical data on key dimensions and a clear approval route for first samples.
Many automotive buyers expect the foundry to work to a quality system. Read about IATF 16949 to see what the certificate covers, and ask for the certificate with its scope and expiry date. A certificate for one plant does not cover another.
What belongs in every casting specification?
Include these items for all three customer types:
- Material standard and grade, with the required chemical composition and mechanical properties.
- Critical dimensions, tolerances and the datum for each, plus machining allowance.
- Acceptance criteria for defects, such as porosity, shrinkage and inclusions. See casting defects for the common types.
- Tests required, how many pieces, and who witnesses them.
- Marking, traceability by heat or batch number, and packing for export.
How do you control the supply?
Treat the pattern or die as part of the contract. Agree who owns it, where it is stored and what happens if you change supplier. Approve first samples before releasing volume, and inspect each lot before shipment against the agreed plan.
Next step
We find and audit foundries in Gujarat, check samples and have castings tested. To place your casting requirement, book a free sourcing review.