In the production process of cemented carbide wire drawing dies, the surface of the wire drawing die needs to be processed by machine tools. During the processing of the machine tool, the dimensional accuracy and shape and position accuracy are achieved by grinding. Because the grinding force of cemented carbide is 2-3 times that of general steel. Therefore, the grinding machine is required to have high power and high rigidity. As far as my country's current machine tool level is concerned, there is no special grinding machine for processing cemented carbide. Therefore, machining errors are often caused, and the cumulative effect of the errors will seriously damage the service life of the wire drawing die. In the process of EDM, because the wire drawing die material is subjected to a high temperature of about 1000 ℃ at the moment of discharge, the effect and the action of the liquid medium will cause the surface layer to change the metallographic structure, and there may be carburization (carbon in the working fluid). ), metal infiltration (copper and tungsten), and even micro-cracks, which undoubtedly affect the life. In order to enable the alloy to withstand greater impact and extrusion load, whether it is hot-pressed or cold-pressed, the clearance requirements are very strict. Generally, the interference of 0.03-0.05mm is selected for cold pressing inserts, 0.08-0.10mm for hot pressing inserts, the heating of the cavity sleeve is 700-800℃, and the cemented carbide is about 300℃. After the hot pressing is completed, Put it in a 600℃ box furnace for heat preservation to eliminate stress.
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