Sourcing magnesium casting blanks from China

Duty and classification of casting blanks

Heading 8104 covers magnesium and articles thereof, including waste and scrap. This guide concerns magnesium alloy die-casting blanks supplied for further machining. The table repeats the other-magnesium-articles line for different supply conditions; these are not separate tariff subdivisions. Die-cast housings and brackets are classified by what they are, so do not assume that unfinished supply makes them magnesium articles.

Read from the UK Trade Tariff on 1 October 2026, the supplied heading lines carried 0% duty for goods from China. The other-articles line records no anti-dumping or countervailing duty, suspension or attached import control. Suspensions elsewhere in the heading concern unwrought magnesium and specified powder. The scrap line has a waste import control. Waste shipment controls apply only to waste; if importing scrap from China, confirm the applicable requirements with your customs broker before shipping.

Send the drawing, photographs, alloy composition, intended use and machining condition to your broker to confirm the commodity code. For the wider material family, see magnesium alloy billets. The zero-duty statement here applies only where classification remains within heading 8104.

Alloy, casting condition and machining stock

Specify the alloy chemistry, drawing revision, datum surfaces, wall thicknesses and machining allowance around bores, sealing faces and threads. State whether the supplier delivers cast, trimmed, deburred or coated blanks. Separate casting dimensions from the finished dimensions your machinist must achieve.

Agree acceptable porosity locations and inspection methods before production. Ask for trial machining of samples through critical faces and bores, with radiographic or sectioned-sample checks where needed. Record whether welding, impregnation or other repairs are permitted. UK REACH applies to substances in articles; request alloy and coating composition information to assess the relevant obligations.

Worked duty example

Illustrative example, not a quote: 200 magnesium alloy die-casting blanks, assuming this classification; illustrative only under 8104 90 00 00, invoiced at £2,000 free on board, with £800 of freight and insurance to the UK. The customs value is £2,800. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £2,800, so it is £560. 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: match the casting batch to the melt analysis and check sampled blanks against the ordered alloy, including iron, nickel and copper limits.

Geometry: measure from the agreed datums, check distortion and confirm that trimming has left enough stock for machining.

Internal quality: inspect agreed locations for porosity, inclusions and cracks; machine sample sealing faces and bores to reveal hidden defects.

Traceability and arrival condition: match batch labels to reports, check for corrosion and packing damage, and keep suspect batches separate. Set the sampling and acceptance plan in your inspection brief.

What goes wrong

A smooth cast surface can hide porosity that opens during machining. Distortion can leave a sealing face short of stock, while trimming damage or cracks around bosses can make a blank unusable. A certificate without a link to the casting batch does not establish which alloy arrived.

Use approved sample blanks and machining results as the acceptance reference. Agree how the factory reports repairs and rejects, then check production batches against the same drawing and defect criteria. Inspect arrival packaging for moisture and abrasion before releasing blanks to machining.

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.