What are the UK CBAM default values for steel nuts and washers?
HMRC's UK CBAM defaults put non-stainless nuts with an inside diameter above 12 mm at 4.890 tCO2e per tonne and self-locking nuts at 4.753. Stainless nuts are 5.166. Plain washers are 4.973, spring and lock washers 2.552, and rivets 2.919.
Default values under heading 7318
- 7318 16 99: nuts, non-stainless, inside diameter above 12 mm: 4.890 tCO2e per tonne.
- 7318 16 60: self-locking nuts, non-stainless: 4.753.
- 7318 16 40: blind rivet nuts, non-stainless: 4.726.
- 7318 16 39: stainless nuts: 5.166.
- 7318 22 00: washers other than spring or lock: 4.973.
- 7318 21 00: spring and lock washers: 2.552.
- 7318 23 00: rivets: 2.919.
- 7318 24 00: cotters and cotter pins: 2.902.
Same buyer, different numbers
A kit of bolts, nuts and washers can fall under three codes with three defaults. If the parts are declared separately, each needs its own weight and figure.
What Senseible does here
Senseible reads wire rod and bar purchases with heat treatment fuel by product code, so your own figure can be set against each default. We build the figure from your records and check every figure in-house; for the UK it must then be verified by a verifier accredited for UK CBAM. Have your own verifier? Send it to them.
Sources: HMRC, UK CBAM iron and steel default values (published 16 October 2026)
Last reviewed 2026-11-02.