Aluminum is one of the most used metals in today’s society – Aluminium Doors Durban in Gauteng it can be found across a number of industries, such as construction and commercial, and in a number of applications, such as beverage cans and appliances. When choosing a manufacturer of aluminium extrusion for supplying the metal that you use in your workplace, however, it is important that you carefully consider which one will be best for your needs.
The manufacturer will begin by removing the aluminium from deep within the earth’s crust (either as bauxite ore or feldspar). Often, the Bayer’s method, Wohler’s method or Hall Heroult method is chosen to remove the metal in its molten form. It is then hardened and moulded into whatever shape the manufacturer desires. When the aluminium is extracted from the earth in its solid form, Aluminum Extrusions For Glass it will be passed through a number of mechanical processes that are designed to give the metal its desired shape. These processes include: rolling, drawing, forging, spinning, piercing and extrusion.
Regardless of whether aluminium has been found in its molten or solid form, the manufacturer will then pass it through either a hot working or cold working process to prepare it for their customers. When using the hot working process (the most popular of the two), a billet will be heated to a temperature of over 79 degrees Celsius, which will allow the aluminium to be easily distorted and placed into its desired shape.
The reason for the popularity of the hot working process over the cold working one can be fully realized when you compare aluminium extrusion to squeezing toothpaste out of its tube. It is much easier to extrude the metal when it is malleable, meaning that it must have been heated to a certain temperature.
Finally, the aluminium will pass through an extrusion and drawing process that runs almost parallel to each other. This is the final step in the whole extrusion process and is the step that gives the metal its entire shape. Deep drawing, for example, is used give the metal a cup, conical tapered, cylinder and seamless tube shape. For less curved shapes, Window Frame Extrusion the drawing process is skipped.
Once you are satisfied with the processes and methods utilized by a potential manufacturer of aluminium extrusions, you can begin submitting your orders with them. If, after your first delivery, you are still satisfied with the manufacturer based on the promptness of the order being filled and the quality of the aluminium that you receive, you can continue the relationship.
Aluminium Doors Durban in Gauteng?
When double glazing first became a popular window choice in the 1960s, most frames were made of aluminum. Aluminum remained the most popular choice for framing double glazing windows through the mid-1980s, when it held over 60% of the market. Since the introduction of PVC window framing, the market share of aluminum framed windows has dropped steadily. As of 2003, less than 17% of windows sold were aluminum framed. There are many reasons for the drop in popularity - and still some good reasons for choosing aluminum over PVC or wood frames.
The early popularity of aluminum was based on price and convenience. Aluminum was far less expensive than wood, the only other choice for window framing in the early years of double glazing. In addition, aluminum is easily extruded in the shapes and lengths needed to frame windows of any shape or size. It's strong, durable and very close to maintenance free.
Aluminum frames do have one significant drawback, however. Aluminum is an excellent conductor of heat and cold. It's such a good conductor, in fact, that in colder temperatures, frost often forms on interior surfaces of the windows close to the aluminum joints. The end result is windows that are significantly less able to conserve heat and energy than those framed in other materials.
PVCu was introduced in the mid-80s as a choice for framing double glazing windows, and immediately began to climb in popularity. When compared with aluminum frames, PVCu was less expensive, and more energy conservative. It can't match the strength of aluminum, however, and there are security concerns with its use. In addition, the introduction of 'thermal breaks' reduces the heat conductivity (measured in U values) of aluminum framed windows significantly. By fitting a less conductive material between the panes of the window as a sort of 'bridge' between the glass, manufacturers can bring the U value of aluminum framed double glazed windows within conservation standards.
The main selling points for aluminum window frames, then, were:
1. Strength - aluminum framed windows are far less prone to warping. The aluminum withstands weather well, needs no painting and forms strong, rigid window frames that will fit for far longer than wood frames.
2. Cost - aluminum frames are far less expensive than wood frames. They are easier to manufacture, and the material is less expensive to begin with. On the other hand, the introduction of PVC has largely negated the advantage of cost. Far lower in price, and with more efficient heating, PVC has become the material of choice for framing double glazing windows.
3. Ease of maintenance - As opposed to wood, which is subject to warping and decay and needs repainting every 3-5 years, aluminum is virtually maintenance free. It never needs painting, doesn't rot or warp, and is rigid and strong enough to bear the load of window lintels with minimal reinforcement.
4. Security - Because of the tight fit possible with aluminum framed double glazed windows, they were - and still are - the choice where security is a paramount concern. It's very difficult to 'pop' an aluminum framed window from its frame if it's properly fitted.
Greenhouse Kit Frames
High strength aluminium alloys.
The origin of aluminium alloys in aircraft construction started with the first practical all-metal aircraft in 1915 made by Junkers in Germany, of materials said to be `iron and steel'. Steel presented the advantages of a high modulus of elasticity, high proof stress and high tensile strength. Unfortunately these were accompanied by a high specific gravity, almost three times that of the aluminium alloys and about ten times that of plywood. Aircraft designers during the 1930s were therefore forced to use steel in its thinnest forms. To ensure stability against buckling of the thin plate, intricate shapes for spar sections were devised.
In 1909 Alfred Wilm, in Germany, accidentally discovered that an aluminium alloy containing 3.5 per cent copper, 0.5 per cent magnesium and silicon and iron, as unintended impurities, spontaneously hardened after quenching from about 480°C. The patent rights of this material were acquired by Durener Metallwerke who marketed the alloy under the name Duralumin. For half a century this alloy has been used in the wrought heat-treated, naturally aged condition. The improvements in these properties produced by artificial ageing at a raised temperature of, for example, 175°C, were not exploited in the aircraft industry until about 1934.
In addition to the development of duralumin (first used as a main structural material by Junkers in 1917) three other causes contributed to the replacement of steel by aluminium alloys. These were a better understanding of the process of heat treatment, the introduction of extrusions in a wide range of sections and the use of pure aluminium cladding to provide greater resistance to corrosion. By 1938, three groups of aluminium alloys dominated the field of aircraft construction and, in fact, they retain their importance to the present day. The groups are separated by virtue of their chemical composition, to which they owe their capacity for strengthening under heat treatment.
The first group is contained under the general name duralumin having a typical composition of: 4 per cent copper, 0.5 per cent magnesium, 0.5 per cent manganese, 0.3 per cent silicon, 0.2 per cent iron, with the remainder aluminium. The naturally aged version was covered by Air Ministry Specification DTD 18 issued in 1924, while artificially aged duralumin came under Specification DTD 111 in 1929. DTD 111 provided for slight reductions in 0.1 per cent proof stress and tensile strength.
The second group of aluminium alloys differs from duralumin chiefly by the introduction of 1 to 2 per cent of nickel, a high content of magnesium and possible variations in the amounts of copper, silicon and iron. `Y' alloy, the oldest member of the group, has a typical composition of. 4 per cent copper, 2 per cent nickel, 1.5 cent magnesium, the remainder being aluminium and was covered by Specification DTD 58A issued in 1927. Its most important property was its retention of strength at high temperatures, which meant that it was a particularly suitable material for aero engine pistons. Its use in airframe construction has been of a limited nature only. Research by Rolls-Royce and development by High Duty Alloys Ltd produced the `RR' series of alloys. Based on Y alloy, the RR alloys had some of the nickel replaced by iron and the copper reduced. One of the earliest of these alloys, RR56 had approximately half of the 2 per cent nickel replaced by iron, the copper content reduced from 4 to 2 per cent, and was used for forgings and extrusions in aero engines and airframes.
The third and latest group depends upon the inclusion of zinc and magnesium and their high strength. Covered by Specification DTD 363 issued in 1937, these alloys had a nominal composition: 2.5 per cent copper, 5 per cent zinc, 3 per cent magnesium and up to 1 per cent nickel. In modern versions of this alloy nickel has been eliminated and provision made for the addition of chromium and further amounts of manganese.
Aircraft structural aluminium.
Of the three basic structural materials, namely wood, steel and aluminium alloy, only wood is no longer of significance except in laminates for non-structural bulkheads, floorings and furnishings. Most modern aircraft still rely on modified forms of the high strength aerospace aluminium alloys which were introduced during the early part of the 20th century. Steels are used where high strength, high stiffness and wear resistance are required. Other materials, such as titanium and fibre-reinforced composites first used about 1950, are finding expanding uses in airframe construction.