Stainless steel grades pre-dominantly used for balustrade purposes are AISI 304 and AISI 316
AISI304 – INTERNAL
AISI316 – EXTERNAL
These two grades appear the same on inspection but perform differently dependent upon their surrounding environment. This is in part due to their difference in chemical composition.
AISI 316 offers more resistance to corrosion due to an element called molybdenum.
The final consideration is the surface finish of the stainless steel. Normally satin and mirror polished are the standard but these two surface finishes can look significantly different when polished with varying grade sanding belts.
Mirror polished material for example is polished down to approximately 0.2 microns so that the surface is completely smooth to the touch, shows no grain resulting in a surface very similar to that of a “mirror”. This makes it the most suitable finish to be used in and up to an area of 10Km from the coast.
Satin polished material is taken down to approximately 0.5 microns and the grain can be clearly seen.
Normally micron values are converted to grit readings which appertain to the type of “sanding” belt used to achieve the relevant finish. Croso UK’s standard satin finish is 320 grit minimum.
Warning:- If ordering tube from an alternative source, “off the shelf tube” can be polished from from 120 grit to 240 grit, this has the effect of appearing dull in comparison to our fittings.
| Grade / Area | Satin 304 | Satin 316 | Mirror 304 | Mirror 316 |
|---|---|---|---|---|
| Rural | Internal |
Internal External |
Internal External |
Internal External |
| Urban | Internal |
Internal External |
Internal External |
Internal External |
| Industrial |
Internal External |
Internal External |
Internal External |
|
| Coastal | Internal | External |
Internal External |
If in doubt, please ask one of our sales team who would be more than happy to help.
