Our strip steel can be delivered with several different surface finishes. To describe a surface appearance correctly one has to indicate both its appearance and its roughness.
Surface appearance
In the table, surface appearance is defined in terms of brightness and color. Stainless steels are not usually color tempered and are, therefore, not delivered in codes 6 and 7.
| Code | Surface | Definition |
|---|---|---|
| 0 | No requirements | Normally an oxidized surface for which there are no appearance requirements |
| 2 | Dull | Dull smooth surface |
| 3 | Bright | Normal bright smooth surface |
| 4 | Very bright | Mirror surface meeting very stringent requirements on uniform appearance |
| 6 | Yellow | Yellow, oxidized surface with uniform color |
| 7 | Blue | Blue, oxidized surface with uniform color |
| 8 | White | Surface free from oxide discoloration and with uniform color |
| 9 | Special | Surface as specified by customer |
Surface roughness
Surface roughness is measured with a special trailing stylus instrument. The relevant terminology and measuring methods can be found in EN ISO 4287 and EN ISO 4288.
| Class | Class limit Ra µm (µin.) |
Class mean Ra µm (µin.) |
|---|---|---|
| Y2 | 3.2- 8 (126-315) | 5.0 (197) |
| Y3 | 1.6- 4 (63-157) | 2.5 (98) |
| Y4 | 0.8- 2 (31- 79) | 1.25 (49) |
| Y5 | 0.4- 1 (16- 39) | 0.63 (25) |
| Y6 | 0.2- 0.5 (8- 20) | 0.32 (13) |
| Y7 | 0.1- 0.25 (4- 10) | 0.16 (6) |
| Y8 | 0.05- 0.125 (2- 5) | 0.08 (3) |