Carbide Specifications Anvil Defects Eliminated

The flaw as micropore and so forth in the cemented carbide will made material brittle fracture. Especially the flaw in big size cemented carbide is more difficult to prevent the brittle fracture. This paper says how to achieve the cemented carbide of high compact and high strength. Research the product technology of compacting and sintering process about cemented carbide anvil in systematic, regularity about different process date influence resist break strength, Seeked the principle about eliminate the flaw in cemented carbide.Through the reaseach about process make clear: Compacting slowly and equally as common single-action pressing, also can produce good anvil compact. Pattern about ejection process gradually with 0.5mm/sec and top punch hold down can avoid compact crack by spring back. From pressing equation LgP=LgP_max-L(β-1) can know, want to get complete compact big size anvil compact, cold isostatic pressing can provide pressing pressure and make compact all kinds direction equally compact. The big size anvil used wax as plasticizer at dewaxing. The main dewax stage from 270℃ to 400℃. Have gas release summit between 400℃ and 750℃. Setting up rational process date at dewax stage can prevent cemented carbide crack. But the crack will appear and impair the quality of products when the microcrack flaw inner compact. Resistance about capillary pressure of big size anvil at high sintering temperature is P_r,thevalue of resistance about capillary pressure calculate in this paper Pr =3.96 x 106Pa. Pressure of gas pressure sintering P=5 * 106Pa>Pr, pore in sintering blank can be remove. The length of pore 2a can be decreased when cemented carbide quickly cool as 13°C/min from 1420°C to 1300 °C. The distance of surface tension to flaw A t will increase. The cemented carbide used quickly cool is equal to reduce sintering time at high sintering temperature,the extremely growth of tungsten carbide grain be restrained, made the tungsten carbide grain more equal,so the strength of cemented carbide improved.