Sourcing cast iron grinding balls from China

Duty on cast iron grinding balls

Read from the UK Trade Tariff on 1 October 2026, the supplied extract records 0% duty for Chinese-origin grinding balls and similar articles for mills under 7325 91 00 00. It records no anti-dumping or countervailing duty, suspension, steel measure or attached import control for this line.

Heading 7325 covers other cast articles of iron or steel. This guide focuses on cast iron grinding balls for mills. The table shows buying variants under the same tariff line, rather than separate commodity codes. See the wider castings guide for covers and other castings.

Give your customs broker the material specification, casting process and intended mill use to confirm the classification through finding your commodity code. Budget for 20% import VAT separately from customs duty. The duty and VAT guide explains the calculation.

Specify chemistry, hardness and mill conditions

State the cast iron grade and agreed chemical composition, including chromium content where relevant. Specify ball diameter, permitted variation, size mix, heat treatment and hardness testing method. Ask for both surface and sectioned-ball hardness results, with samples traceable to the production melt. Agree how cracks, internal cavities and breakage will be assessed.

Describe the mill, liner material, feed and whether grinding is wet or dry. For wet service, describe the slurry chemistry. Suppliers must supply safe work equipment. Ask for handling and use information, and agree a trial using your process material before accepting the production batch.

Worked duty example

Illustrative example, not a quote: Illustrative batch of cast iron grinding balls for a small processing business under 7325 91 00 00, invoiced at £30,000 free on board, with £4,000 of freight and insurance to the UK. The customs value is £34,000. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £34,000, so it is £6,800. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Chemistry and traceability: match melt identifiers on packing records to the material reports. Test production samples against the agreed composition.

Dimensions and mass: measure ball diameter and roundness across the supplied size mix. Compare delivered net mass with the order and check for mixed sizes.

Hardness and soundness: verify surface and internal hardness using the agreed method. Examine sectioned samples for cavities and cracks, and witness the agreed impact or breakage test. Include these checks in your inspection brief.

Packaging and arrival: check drums or bags, restraints, batch labels, moisture and loose balls before unloading. For imported solid wood packaging, a certificate cannot replace the ISPM15 mark. Photograph damaged packaging and keep affected batches separate.

What goes wrong

A ball can meet surface hardness while its centre has a different hardness or contains shrinkage cavities. Incorrect chemistry or heat treatment can cause rapid wear, cracking or fragmentation in service. A supplier's test on a selected sample does not establish the condition of the delivered batch.

Mixed diameters change the mill charge, while broken packaging can release heavy balls during unloading. Agree batch sampling, test methods and acceptance criteria in the order. On arrival, retain labelled samples and compare wear and breakage in your process before mixing the new supply with existing stock.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.