| 摘要 |
Cemented carbide tool insert/button for mining and construction comprises hard constituents in a binder phase of cobalt and/or nickel and surface portion(s) and an interior portion. The grain size of the surface portion is smaller than in the interior portion. The surface portion with the fine grain size has a lower binder phase content than the interior portion. - An INDEPENDENT CLAIM is included for a method of making a cemented carbide body with a wear resistant surface zone comprising: providing a compact of cemented carbide from a single powder; possibly presintering the compact and grinding to desired shape and size; placing a powder of grain refiner containing carbon and/or nitrogen on portion(s) of the exposed surface of the compact/presintered blank, preferably containing chromium; sintering the compact/presintered blank and grain refiner powder so as to diffuse the grain refiner toward the center of the body, forming a surface zone inwardly from the exposed surface on which the grain refiner was placed, and forming an interior zone; possibly adding an isostatic gas pressure during the final stage of sintering to obtain a dense body; possibly post-HIP-ing at a temperature lower than the sintering temperature and at a pressure of 1-100 MPa; possibly grinding to final shape; possibly removing undesired carbides and/or graphite from the surface using grinding and/or any other mechanical method, with the sintering performed for a time enough to obtain a dense body with a surface portion having a smaller grain size and lower cobalt content than in the interior portion. |
