Coatings on metal fasteners -- Specification for sherardized coatings
This part of BS 7371 specifies requirements for sherardized coatings on iron and steel fasteners and accessories applied by thermal diffusion of zinc powder onto a component’s surface.
NOTE Hydrogen embrittlement is not induced as a result of this coating process.
The coating consists of zinc/iron alloys, which are subsequently treated using either a zinc phosphate treatment (see BS 7371-9:1996, Type 2) or a suitable substitute treatment similar to those used in electroplating zinc (see BS 7371-3:2009) and mechanical plating (see BS 7371-7:2010). This results in a dust free surface, which, when required, can be lubricated to give controlled torque/clamping force properties (see BS 7371-2:1993).
In addition to the requirements in this part of BSÂ 7371, the requirements in BSÂ 7371-1:2009 that are applicable to sherardized coatings apply.
This part of BSÂ 7371 also specifies requirements for:
the local coating thickness for six grades of coating;
possible types of post treatment;
the assessment of corrosion resistance of unused coated parts when subjected to neutral salt spray testing (see BSÂ ENÂ ISOÂ 9227:2006).
| SDO | BSI: British Standards Institution |
| Document Number | 7371-8 |
| Publication Date | March 31, 2011 |
| Language | en - English |
| Page Count | 20 |
| Revision Level | |
| Supercedes | |
| Committee | FME/9/-/1 |