| 摘要 |
<p>WIRE DRAWING DIE AND METHOD OF MAKING THE SAME A wire drawing die employing a synthetic hard, wearresistant material, such as a polycrystalline aggregate of synthetic diamond or a polycrystalline cubic boron nitride includes a metal casing having flat, parallel front and back sides. A cylindrical cavity is formed in the front casing side having a flat bottom, the side wall of the cavity being undercut adjacent the bottom. A first layer of metal powder is deposited in the casing cavity covering the bottom and the undercut. An annular metal blank having flat opposite sides and a core formed of the hard, wear-resistant material is placed on the first metal powder layer and adhered thereto, the core being concentric with the cavity. A second layer of metal powder is deposited in the cavity covering the first layer and the blank, the metal powder of both layers having a melting point lower than the thermal degradation temperature of the core. A cylindrical cavity having a flat bottom is formed in one end of a cylindrical plug, the inside diameter of the plug cavity adjacent the bottom being greater than that at the one plug end. The plug is inserted in the casing cavity with the plug cavity facing the second metal powder layer until the plug cavity bottom engages the second metal powder layer, and pressure is applied to the plug to compress the metal powder layers. The casing is then heated for a time and at a temperature sufficient to melt the metal powder, but at a temperature less than the thermal degradation temperature of the core thus forming a body of molten metal which encapsulates the blank. The pressure and heating is then terminated and the casing is cooled to solidify the metal body to secure the plug and blank in the casing cavity. Countersunk openings are formed in the back side of the casing and the other end of the plug which respectively extend through the metal body to the core, and a die opening is drilled through the core communicating between the countersunk openings.</p> |
