Material Specification
Aluminium
Our poles are produced from 6060T5 Aluminium alloy, the brackets and other tubular elements from 6060T6 alloy, the backing plates from 5038H111, the resistance elements from AlSi7Mg or AlSi10Mg cast Aluminium and decorative parts in AlSi13 cast Aluminium.
These Aluminium alloys comply with NF EN 755 series standards for conical posts, brackets and other tubular parts as well as backing plates, and standard NF EN 1706 for parts in cast Aluminium.
Bars, tubes and spun profiles - 6060T5 or T6:
The mechanical characteristics are obtained by tempering and rendering. Valmont’s specific rendering treatment makes it possible to obtain above-standard mechanical characteristics. The 6060 alloy is a good compromise between mechanical strength and corrosion; it is particularly apt for anodising and cold deforming. Good welding results are obtained with classic procedures under inert gas (TIG or MIG).
Piece of cast Aluminium AlSi7Mg and AlSi10Mg:
There are two main casting processes used - sand or shell - according to the geometrical complexity of the product, the degree of precision needed for the dimensions and the quantities to be produced. According to the level of resistance required, the pieces can be heat treated.
The Aluminium Process
Valmont aluminium columns are formed via cold tapering.
After the aluminium tubes have been received and stocked in the production workshop, the tubes are then cut to length according to the technical specifications of the products to be manufactured, and automatically put into a storeroom for rough products. When they leave the storeroom, the tubes are automatically taken to the tapering machine.
The tapering operation consists of cold embossing the raw tubes to give them the required shape. This process is
called cold spinning treatment. This spinning machine is made of a broach and a tailstock, which turns the raw shaft, then a shaping carriage made up of specific rollers moves along it and models the product following the technical specifications programmed into the machine.
Depending on the size of the end products, 1, 2, 3 or 4 can be made from one raw shaft. Once tapered, the raw shaft is moved to a saw bench where it will be cut to length. This whole tapering process is entirely automatic: the 3D product models made by our design department are directly sent to the machine’s digital controls; the operator checks the data and then launches the production process.
This expertise and the machine’s technical abilities allow us to produce complex shapes and obtain large tapering ratios.
The Aluminium Production Line
A rendering furnace, where the rough tapered tubes are heated for 6 hours to acquire the mechanical strength fixed by our technical specifications. The products are checked as they leave the furnace to ensure that our products are well above minimum values.
After cooling, the tapered tubes are straightened and sent to the polishing line. 2 polishing operations are performed on 2 specific machines: the first gives a rough polish and the second carries out the finishing, which gives the end product that brushed and polished appearance.
The next stage is cutting the door. The tapered tube is held in clamps and a horizontal saw with a thin band saw blade does the cutting. Thus the door is perfectly adjusted in relation to the shape cut in the column. On the same machine, we
reinforce the opening if necessary. This operation consists of expanding a strengthening tube inside the pole.
The last stage on this line is welding the base plates; this is done by qualified welders.
The column thus produced are moved to a storage zone within the factory. Access doors are equipped and assembled. Any specific operations seen to be necessary are performed, followed by the final control before individual packing and sending them to the client, putting them in stock or sending them for painting on our powder coating line.