| 摘要 |
899,453. Extruding; working at specified temperatures. COMMISSARIAT A L'ENERGIE ATOMIQUE. Jan. 22, 1960 [Jan. 27, 1959], No. 2385/60. Class 83 (4). In the extrusion of a billet 5 from a container 1 through a die 3 using a lubricant 4, a frangible closure member 2 is placed in or adjacent the die orifice to cause distribution of the lubricant throughout the space 10 between the billet and container upon initial application of pressure, the closure member being subsequently broken by the extrusion pressure. The closure member 2 may be of soft steel, nickel-chrome steel, bronze, brass, copper, aluminium bronze, gun-metal, rolled zinc, lead, tin, polyamide, phenol formaldehyde, polyvinyl chloride, polyolefine, cellulose or cellulose ester or polyester; it may be of cup shape placed between the die 3 and the end of the container 1. A further closure member 7 may be placed between dummy blocks 6, 8 or between a dummy block and the billet. The latter may have a conical leading end to enter the conical orifice of the die 3. In another embodiment, Fig. 3, the closure comprises a conical slug 13 placed in the die orifice. A separate sealing collar 14 of alloy steel is provided; a hemisphericalshaped closure may be used with certain dies. In a further embodiment, Fig. 4 (not shown), the die has a conical aperture and a conical outer surface fitting into a conical end of the container. The closure consists of a flat disc fitting between the outer surface of the die and a support plate therefor; a separate cylindrical liner is used as a packing. The lubricant used depends upon the temperature of extrusion and may be oils, greases, metallic soaps such as stearates of aluminium, zinc or magnesium which may be mixed with grease or fatty substances with graphite or molybdenum disulphide or a mixture of colloidal graphite with paraffin or with an organic resin. Specific examples are given for the extrusion of copper at 800- 900‹ C., brass at 700‹ C., phosphor-bronze or silicon-bronze or lead bronze at 800-900‹ C., magnesium or magnesium alloy at 300-500‹ C. and zinc or zinc alloy at 250-300‹ C. |
