Materials and Finishes
Uncontrolled corrosion is a recurrent problem with all applications involving metals, it may lead to a reduction in the performance and the lifetime of the installation. Cable trays are mainly exposed to atmospheric corrosion. The environment in which the cable trays are installed is therefore the main criteria in the choice of surface treatment, or type of steel.
Atmospheric corrosion affecting metals involve a chemical reaction between the iron found in steel and dioxygen in air or water (condensed moisture, rain, or spray). The reaction produces the chemical compound Fe(OH)3, more commonly known as rust.
Galvanic protection of steel is a sacrificial process. Zinc, in contact with an oxidising agent, is converted into zinc hydrocarbonate (white) thus protecting the steel.
Steel Grade Quality
Our tray is constructed of precision engineered, high quality steel wire. ISO 9000 certified, Legrand/Cablofil wire cable tray is subjected to rigorous quality control at every stage of the manufacturing process.
Electrogalvanising after manufacture
ASTM A633 Standard
The cable tray, manufactured using untreated steel wire, is pickled and then immersed in an electrolyte containing zinc. Zinc is then deposited on it by passing an electric current. A smooth blue-grey, fairly glossy appearance is obtained to a greater or lesser extent depending on the pH value of the electrolytic bath used. The color and level of gloss have no negative or positive effect on the corrosion resistance of the coating.
Hot dipped galvanized after manufacture
ASTM A123 Standard
The cable trays or accessories, manufactured from untreated steel sheet or wire, are degreased and pickled before being immersed in a bath of molten zinc. The entire product is therefore covered with a thick layer of zinc.
A light grey, rough appearance is obtained.
NOTE: Any white marks due to the formation of zinc hydroxycarbonate which might appear on the surface have no influence on the corrosion resistance.
ASTM F1136 Standard
Geomet is a treatment based on zinc and aluminium. As it does not contain any chromium VI (hexavalent), it complies with the RoHS Directive.
Offering protection equivalent to GC, it is used for small accessories and fixings which are difficult to hot dip galvanize.
Power Coated Paint
ASTM D3451 Standard
Resin-based paint is applied to the cable tray using an electrostatic powder and then cured in an oven. Black is standard. The entire range of colors are available. Mainly used for aesthetic reasons and to help identify cable routes, it offers very good corrosion resistance and the industries only UL classified painted tray system.
When a wire cable tray is cut, the fact that a wire has been cut does not affect the level of protection. The jaws of the bolt cutter drags a layer of zinc across the cut and forms a protective layer.
In particularly harsh environments, selecting the right type of steel is more important than the coating. CABLOFIL uses two austenitic stainless steels, 304 L and 316 L, for their high level of corrosion resistance. This is partly the result of their very low carbon levels ("L" stands for "low carbon") as well as a Cablofil exclusive passivation process.
Stainless Steel 304 L - ASTM A380 Standard
AISI 304L - X2CrNi18.09
Offers good corrosion resistance against soft water, normal environments and food products (except mustard and white wine).
Stainless Steel 316 L - ASTM A380 Standard
AISI 316L - X2CrNiMo17.12.2
Since it contains molybdenum, stainless steel 316L is able to resist intergranular corrosion. This makes it particularly suitable for the chemical and food industries, the nitrate explosives industry and environments containing halogen (fluorine and chlorine).
Decontamination of stainless steels
There are two key stages for prolonging the service life of the product and, by implication, the installation:
Pickling in acid after degreasing eliminates pollutants.
Passivation artificially creates a film of chromium oxide on the surface of the steel.
Corrosion-resistance tests involving salt spray and SO2 (sulphur dioxide) highlight the importance of these two processes.
Pickling and passivation give CABLOFIL's stainless steel a very clean uniform and a distinctly matte finish.
All CABLOFIL stainless steel products are pickled and passivated.
Pickled and Passivated
Pickled and Passivated
Corrosion is the result of an electrochemical phenomenon caused by a difference in potential between different metals, or between a metal and the impurities within it when they are connected electrically.
It is important to understand this phenomenon if you want to be sure of selecting the best supports, fixings and earthing terminals. This will ensure that surface treatments are compatible: