| 摘要 |
882,693. Extruding; welding by pressure; working at specified temperatures; making composite metal strip or rod. JOHNSON, MATTHEY & CO. Ltd. May 24, 1960 [July 10, 1959], No. 23814/59. Classes 83 (2) and 83 (4). Bi-metallic or multilayered strip or rod 21 is made by extruding simultaneously two or more separate billets 19, 20 of different metals or alloy, from separate containers 5, 6 through a common die 4. In the manufacture of silver-copper bi-metal strip, a heated billet of silver 19 is extruded by a ram 11 and simultaneously a heated billet of copper 20 is extruded by a ram 12. An extrusion temperature of 750‹ C. is used to ensure that the silver and copper layers are pressure welded together. The rams are operated by double-acting pistons 9, 10 working in cylinders 2, 3 having fluid ports 13-16. Separate pistons 18 working on a cross head 17 maintain a seal between the containers 5, 6 and die 4 during extrusion. The billets 19, 20 may be of the same cross-sectional area in which case the extrusion speeds of the two rams 11, 12 are adjusted to obtain the required proportion of metals in the bi-metal strip 21. Alternatively, the billets may have different areas whereby the rams are driven at the same speed and may be actuated or controlled by a common mechanism. The press may have its containers disposed on one side of the die or in an alternative embodiment a vertical press may have parallel containers arranged above or below the die. The billets may be of solid metal or of pressed and sintered metal powder. Other examples are given of overlay, inlay or edge-lay bi-metal strip formed of silver and steel, silver and phosphor bronze or silver and cadmium. One of the layers may be discontinuous.
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