Materials and Finishes for Fasteners and Fixings
Whilst our customers most typically require security screws and general fixings in steel (self colour or zinc plated) or stainless steel, additional finishes may be in stock for many of our standard screws, nuts, bolts and other fixings, including:
A black lacquer applied to steel and baked to harden, for a smooth, glossy finish. A high bitumen content provides a quick-drying and durable protective finish. Consists mostly of an asphaltic base dissolved in naphtha or turpentine.
A black oxide coating used on steel parts (not stainless). The black coating is formed by a reaction between the surface of the material and the salts in the black oxide solution. As with Stayblack the coating has a negligible effect of the dimension of the fixing.
Chrome plating adds a thin layer of chromium by electro plating. This type of coating is decorative as well as providing corrosion resistance.
Electro brass plated
Process where a thin layer of brass is applied to the fixing for decorative effect.
In this process the fixing is hot dipped in zinc to prevent corrosion. The galvanised coating is quite think, so clearance holes and nuts will need to be tapped oversize to accommodate galvanised bolts. Generally only available on fasteners M8 and above.
This zinc flake anticorrosive, low thickness coating is designed to provide consistent tightening performance, even at high temperatures. It can be used with a top coat if required. Various types of Geomet coating are available providing a range of levels of corrosion protection.
Green chromate is a coating applied to galvanised or zinc plated parts to make them more durable by protecting the zinc from white corrosion, which can be formed if a galvanised product is exposed to moisture for an extended period.
Like chrome plating, nickel plating adds a thin layer of nickel to the surface of the fixing.
Sheradising is a form of zinc coating, applied using a diffusion process which results in a very resilient and uniform coating with a matt grey appearance. This is a hard wearing and corrosion resistant zinc finish and is covered by BS 4921, with 2 standards of thickness, 15 or 30 microns. Paint or powder coatings can be applied.
Stayblack finish (for stainless steel items)
Stayblack is a non-electro process used on stainless steel to create a matt black coating. It does not affect the corrosion resistance and maintains its appearance under atmospheric conditions and temperature up to 500°C. This type of finish is used mainly in the automotive and aerospace industries.
Zinc and de-embrittled
A plating process can introduce hydrogen atoms between the fixing and the coating, which can cause the fixing to become brittle. De-embrittling means that a further baking process has taken place to remove any hydrogen which may remain and results in a more resilient fixing.
Zinc and yellow plated (gold colour)
Zinc plating gives a protective layer to the fixing which gives a good level of corrosion prevention. Further protection is obtained by adding a passivate which results in a yellow (or gold) finish.
Screws and fixings can also be made to order using the following special materials
- Mild steel
- HT steel grade 8.8
- HT steel grade 10.9
- HT steel grade 12.9
- A2 stainless steel
- A4 stainless steel
Other finishes and materials are available on request – please contact us for advice about suitable finishes for your application.
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Specials and non standard fixings
Looking for fixings with an unusual head diameter or thread length?
Need fasteners with a non-standard finish?
Or do you have other special requirements? Custom fasteners are no problem for Fastenright!
Our skilled technicians can offer a range of services including:
- Screw cutting and machining
- Thread locking and sealing