| 摘要 |
1,069,742. Extruding. CALUMET & HECLA Inc. June 24, 1964 [July 15, 1963], No. 26202/64. Heading B3P. In the hot working of refractory metal or alloy, having a melting-point above 4000‹ F., such as tungsten, rhenium, tantalum, molybdenum, columbium or their alloys, a billet 10 is coated with a softer metal 32 such as copper, nickel or steel to provide a lubricant during working. The coating is made air-tight and, for certain refractory metals, a barrier layer of mild steel or molybdenum may be provided under the lubricating metal, Fig. 6 (not shown). Solid and hollow billets are described, Figs. 2-7 (not shown). They are heated in a gas furnace, inserted in the press container 12 and extruded through die 16 by ram 24. A mandrel 28 is used when extruding tubes. During extrusion a lubricant of graphite and grease is also used. The coating is removed subsequently by acid leeching. A specific example is given for extruding a molybdenum base alloy containing titanium and zirconium. |
