Sourcing fused quartz furnace rings from China

Duty and classification for furnace rings

Read from the UK Trade Tariff on 1 October 2026, heading 7020 covers other articles of glass. Ordinary fused quartz furnace rings are candidates for 7020 00 10 90. Consider 7020 00 05 00 only where the article meets the description of a quartz holder designed for semiconductor diffusion or oxidation furnaces. The remaining table rows compare other glass materials.

The supplied tariff snapshot shows 0% duty for goods from China, with no anti-dumping or countervailing measure and no listed suspension. The ordinary fused quartz line attaches cat and dog fur import and export controls. Imports and exports of that fur and products made from it are banned. Specify plain quartz rings without fur-containing additions and ask your customs broker to confirm the declaration requirement.

Confirm the commodity code using the material certificate, drawing and intended furnace function. A supplier's description of a ring as a semiconductor part does not establish that it meets the holder description. See the fused quartz furnace tubes guide for the wider heading.

Ring geometry, purity and furnace service

Specify fused quartz or fused silica grade, purity, metallic impurity limits, hydroxyl content and acceptable bubbles or inclusions. Ask for a material certificate linked to the production batch. Record the furnace atmosphere, operating temperature and heating and cooling cycle so the factory can assess the proposed material.

Supply a drawing showing inside and outside diameters, axial thickness, concentricity, face flatness, grooves, chamfers and surface finish. Identify the surfaces that locate, seal or support adjoining parts. Agree a sample fit check and a thermal-cycle test matching the intended service.

General workplace safety law applies to articles for use at work where more specific product safety law does not apply. Settle the applicable safety position before supply, alongside practical evidence of fit and thermal performance.

Worked duty example

Illustrative example, not a quote: Illustrative batch of custom-machined fused quartz furnace rings under 7020 00 10 90, invoiced at £15,000 free on board, with £1,200 of freight and insurance to the UK. The customs value is £16,200. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £16,200, so it is £3,240. 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

Material: match batch certificates to the order and check impurity and hydroxyl results against the agreed specification.

Geometry: measure bore, outside diameter and thickness; check concentricity, face flatness and groove position against the approved drawing.

Condition: inspect edges and contact faces for chips, cracks and grinding damage; examine bubbles, inclusions and residual stress on agreed samples.

Packing: check that each ring is separately supported without hard contact between pieces; inspect for transit damage on arrival. Agree the scope of quality inspection before dispatch.

What goes wrong

A ring can match its nominal diameter yet rock on an uneven face or bind because its bore is off centre. Chips around a groove or contact edge can compromise assembly. Substitution of the quartz grade can leave impurity or hydroxyl results outside the agreed limits.

Residual stress and machining damage can emerge as cracks during thermal cycling. Approve the finished sample rather than only a material sample, retain its drawing and certificate, and compare the delivered batch with that approval before fitting it to the furnace.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For own-brand ranges, see sourcing for brands.