Processing, aluminum alloys extrusion

Aluminum. The majority of aluminum containers are of monobloc (one-piece) construction, impact extruded from a slug of lubricated aluminum alloy. These containers are widely used for many products and are available in a vast array of heights and diameters. Because these containers lend themselves to additional shaping, many unusual shapes can be found in the marketplace. They may also be coated after the extrusion process. 

Spray deposition The spray deposition process, which was developed by Osprey Ltd during the late 1970s for producing monolithic alloys [365], has been adapted by several manufacturers to produce particulate-reinforced MMC billets with a residual porosity of 5% [366]. The porosity is eliminated by a secondary processing, such as extrusion or rolling. A spray gun is used to produce an atomized stream of aluminum alloy, into which heated SiC particles are injected. An optimum particle size is... 

In cold extrusion, the metal is made to flow while cold by the application of high pressure. The process is used with any cold workable material, e.g., tin, zinc, copper and its alloys, aluminum and its alloys, and low-carbon soft-annealed steels. 

In 1797, Joseph Barmah patented the first extrusion process for making lead pipes. The metal used to be preheated and ram was hand-driven. In 1820, Thomas Burr built the first hydraulic power press that was to extrude lead pipes (Sheppard 2013). The process was called squirting. By the end of nineteenth century, the extmsion methods were also in use for copper and brass alloys. Alexander Dick invented a hot extrusion process for nonferrous metals in 1894. North America has its first aluminum extrusion process in 1904. In 1950s, Sejounet introduced molten glass as lubricant in extmsion process. 

The core material to be used depends on the actual processing requirements, particularly temperature. It can range from a wax to different ratios of zinc-aluminum eutectic mixtures (alloys) to special fusible eutectic alloys. The core material has to melt below the melt temperature of the plastic. These shaped cores are usually inserted in a mold cavity where it is retained by the mold (such as is used with a mold core puller) or by spiders (as used in certain metal core supports for extrusion dies). After processing, the core material... 

These improvement possibilities are not restricted to injection molds. Thus, in addition to the mold cavities for thermoplastic, thermoset, and elastomer processing, also extrusion molds, slides and jaws, ejector systems, melt control systems and return valves are treated with success. Also for the treatable types of mold materials, the frontiers have been pushed back in recent years. In addition to typical mold steels, nonferrous metals like aluminum or copper alloys can be optimized through different surface and coating technologies. 

Ip, pitting time i, crevice time. Specimens were immersed in 1000 ppmCeCl3 for I week prior to their immersion in aerated 0.S /VNaCI for 90 days, (a) Passivated I month in CeQ3. (b) The SiC/alumimim composite contained 2S voI% of 10 pm SiC particulates, which were mi xed with 6061 alloy powder and processed by extrusion, (c) Hie graphite/ aluminum composite contained 55 vol% of graphite fibers with 8 alternating layers of graphite and aluminum and was clad with a 6061 fiuie sheet of 50 pm thickness. Source Ref 25... 

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