Aluminum is one of the most used metals in today’s society – Aluminium Extruders Sa in Pretoria 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, Stock Aluminum Extrusions 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, Aluminium Structural Framing 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 Extruders Sa in Pretoria?
Greenhouse kit frames may be made of galvanized steel pipe, aluminum, plastic or wood. It is very important when considering purchasing a greenhouse to look at the type of frame it is constructed of. There are also many different grades of these materials used. With the steel pipe frame you not only have to consider the size of the tubing, but also the spacing of the tubing. Naturally, closer spacing of the bows will result in a stronger frame. This is also true of aluminum frames. The thickness of the aluminum, the spacing and the extra supports will all determine the strength. What type of wood is being used is very important also.
Typically the prices going from low to high will be as follows.
1. Plastic frames
2. Lightweight Aluminum Frames
3. Pipe Frames
4. Wood Frames
5. Heavy Duty Aluminum Frames
Some of these such as the wood frames will require maintenance to keep up. The rest of the frame types are typically maintenance free.
Many consumers simply look at size, shape and price and do not consider that at some point they will probably want to add some accessories such as circulating fans, ventilation systems, hanging heaters, misting or fogging systems, etc. to their greenhouse. With plastic frames it is virtually impossible to add any accessories without building a frame to mount the accessories to. Many times these frames simply are not heavy enough to support even a hanging basket. Usually with wood and pipe frames the strength is there, but you will still need to do some extra framing out to mount the accessories. There are also some lighter weight aluminum frame greenhouse kits which will require additional framing to mount your accessories. Most quality aluminum framed greenhouses will offer a channel where bolts will slide to the exact location you desire to put your accessories. Usually this type of frame will even make it possible to add a wire shelf above your benches for extra space.
These are all just general guidelines. It is best to investigate each greenhouse kit on an individual basis.
Understanding The Processes Used In Aluminum Extrusion
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.