New york mcgraw hill publishing company 1986 used

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Unformatted text preview: g Company, 1986. Used with permission. Components for Extruding Hollow Shapes Figure 15.9 (a) An extruded 6063-T6 aluminum ladder lock for aluminum extension ladders. This part is 8 mm (5/16 in.) thick and is sawed from the extrusion (see Fig. 15.2). (b)-(d) Components of various dies for extruding intricate hollow shapes. Source: for (b)-(d): K. Laue and H. Stenger, Extrusion--Processes, Machinery, Tooling. American Society for Metals, Metals Park, Ohio, 1981. Used with permission. Extrusion Processes Hot extrusion Keeping the processing temperature to above the re-crystalline temperature. Reducing the ram force, increasing the ram speed, and reduction of grain flow characteristics. Controlling the cooling is a problem. Glass may be used as a lubricant. Cold extrusion Often used to produce discrete parts. Increase strength due to strain hardening, close tolerances, improved surface finish, absence of oxide layer and high production rates. Extrusion Temperature Ranges for Various Metals C 200250 375475 650975 8751300 9752200 Lead Aluminum and its alloys Copper and its alloys Steels Refractory alloys Extrusion Defects a) Centre-burst: internal crack due to excessive tensile stress at the centre possibly because of high die angle, low extrusion ratio. b) Piping: sink hole at the end of bil...
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This document was uploaded on 03/14/2014.

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