ROUGHNESS COMPARATOR GRIT
A precision nickel comparator plate for grit and shot-blast surface roughness comparison measurement.
The Roughness Comparator is supplied in a protective Wallet.
When steel has been blast-cleaned, the surface consists of random irregularities with peaks and valleys that are not easily characterised.
Because of this random nature, experts have recommended that the profile should be identified as either angular (where grit abrasives have been used) or dimpled (where shot abrasives have been used) and that they should be graded as fine, medium or coarse with each grade being defined by limits specified in ISO 8503.
The Roughness Comparator method is applicable to steel surfaces that have been blast-cleaned with either metallic or non-metallic abrasives to grades Sa 2½ and Sa 3.
When a mixture of shot and grit abrasives are used to blast-clean a substrate, the Grit Surface Roughness Comparator should be used.
Profile Segment 1: Grit 25µm. Shot 25µm.
Profile Segment 2: Grit 60µm. Shot 40µm.
Profile Segment 3: Grit 100µm. Shot 70µm.
Profile Segment 4: Grit 150µm. Shot 100µm.
- ISO 8503-1
- ISO 8503-2
- ASTM D4417