Study On Preparation Technology Of CX2 WC-TiC-TaC-Co Cemented Carbides

In this paper,optimizing component by consulting a large number of related literature and previous experimental results to obtain the component of CX2,studying on the ball-milling process,molding process and sintering process to obtain the preparation process of CX2,and studying on the effect of VC/Cr3C2 to obtain the best combination and quantity of the added inhibitor.Finally,concluded as follows:1?The raw materials are WC powder,Co powder and WC-TiC-TaC solid solution powder,planetary muller was used to refine and uniform mixture the raw material.In the beginning 36h,the particle size reduced very fast,during 36h to 60h,changed very little,after 72h,the particle size began to grow.The ultrafine CX2 composite powder was 0.34?m after 42h ball-milling.2?The composite powers were pressed by compression molding,Compression molding of 200 Mpa with the holding time of 1 min can strengthen the compacts and obtain compacts with density of 6.22g.cm-3 and relative density of 51.2%.3?Sintering the CX2 compacts at 1350°C?1380??1410??1420??1430? in vacuum sintering oven,the result is:the Hc,relative density,TRS and hardness of CX2 increased as the sintering temperature increases at first,and respectively reach the maximum value 18.74KA.m-1,99.4%,1054Mpa at 1420?and 92.4HRA at 1410?.then reduced as the temperature keep elevating,while the relative magnetic saturation reduced as the temperature increases.The optimum sintering temperature for CX2 samples was 1420?.4?With the increased of added quantity of VC in the combined inhibitor(0.2wt.%Cr3C2),the hardness and TRS increased and the relative density decreased,while the He increased rapidly first and then decreased.The Com/Co of samples which added VC/Cr3C2 were lower than undoped ones.The optimum added quantity of Cr3C2/VC was 0.7wt.%,and the value of hardness and TRS reached 92.8HRA and 1256Mpa when added(0.5VC+0.2 Cr3C2)wt.%.The value of hardness and TRS reached 92.5HRA and 1336MPa when added(0.2VC+0.5 Cr3C2)wt.%.Magnified 5000 times with SEM found that most of the WC grain size was 0.4?m?0.5?m,but there existed some rough acicular,flake carbides.It indicated that inhibitors were not evenly distributed,So only a part of the WC grain size were refined,a handful of WC grain became extremely large,The inhibitors had no effect on the grain size of(Ti,Ta,W)C.