Patent ID: 8889063
Filing Date: 2014-11-18
Classification: B22F,F27B,F27D

Abstract:
1. A method of making cutting tools comprising a substrate comprising a hard phase and a binder phase, the method comprising: forming green powder compacts using powder metallurgical techniques; charging the green powder compacts, placed on one or several trays, in a furnace; and sintering the green powder compacts, wherein the furnace comprises an insulation package, at least three individually controlled heating elements located inside the insulation package including a vertical heating element, an upper horizontal heating element arranged in an upper part of the furnace, and a lower horizontal heating element arranged in a lower part of the furnace, wherein sintering comprises a cooling step in which each of the at least three heating elements are individually operated and more than 70% of the total power is applied from the vertical cylindrical heating element such that an average controlled cooling rate from a sintering temperature down to at least a solidification temperature of the binder phase is 0.1-4.0° C./min while a temperature gradient over any one tray in a radial direction is minimized, and wherein the furnace further comprises a thermocouple extending vertically through the center of the furnace through a center hole of the one or the several trays such that the one or the several trays are radially symmetrical about the thermocouple, the thermocouple thereby monitoring the solidification of the binder phase.