How to Source Metal Castings from China (Process, Alloy, QC)

The short answer

To source metal castings from China, provide a drawing (2D/3D) and specify the casting process (sand, investment or die), the alloy, the tolerance grade, any machining and the testing required. Then confirm the foundry actually runs that process and alloy and can hold your tolerance, and require a material certificate and first-article (sample) approval before production.

Figure 1: Sourcing castings — typical steps (indicative).

Figure summary: The main steps are: define casting & material; find foundries; verify process & certs; sample casting; inspect & ship. Sequence and detail vary by product and supplier; verify the supplier and sample before committing to a bulk order.

What to specify

Drawing — 2D with tolerances, and 3D/STEP if available
Process — sand casting, investment (lost-wax) or die casting
Alloy — e.g. ductile iron, grey iron, WCB, stainless, aluminium, bronze
Tolerance grade — general (ISO 8062 / CT grade) and any critical dimensions
Machining & finish — as-cast or machined, surface treatment
Testing — spectro (composition), dimensional, and NDT (UT/X-ray) for critical parts
Annual volume — tooling amortises over volume

Foundry vs. trader

Castings are made in foundries; many "casting suppliers" are traders coordinating foundries. That is not automatically bad — a good trader manages quality — but for critical parts, knowing the actual foundry, its process and its alloy range lets you verify capability. Ask which process and furnace they run and request a tour of the pouring and finishing areas.

How to vet a casting supplier

Alongside general verification:

Material certificate & spectro report tying the casting to the specified alloy
First-article / dimensional report approved before mass production
Process capability — that they hold your tolerance grade routinely, with a sample to prove it
NDT — UT or X-ray for pressure-containing or safety-critical castings

Go deeper

For choosing a casting process and alloy, MFGiq is a manufacturing decision hub that compares processes and materials.

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FAQ

What do I need to get a casting quote from China?

A drawing with tolerances, the casting process, the alloy, machining and finish, and the testing you require. Add annual volume so tooling can be amortised.

How do I confirm a casting matches my spec?

Require a material certificate with a spectrometer report for composition and a first-article dimensional report approved before mass production. Add NDT for critical parts.

Is it a problem if my casting supplier is a trader?

Not necessarily — a good trader manages foundries and quality. But for critical parts, identify the actual foundry and its process and alloy range so you can verify capability.

How to Source Metal Castings from China

The short answer

What to specify

Foundry vs. trader

How to vet a casting supplier

Go deeper

FAQ

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