Composite cutting element containing cubic boron nitride and method of making the same
AssigneeSociete Industrielle de Combustible Nucleaire
InventorsJean M. Cerceau, Yves Boyat
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Abstract
A cutting element of flat shape suitable for use as a drill tip comprises a central abrading blade containing more than 80% vol. CBN sandwiched between two lateral support layers. The lateral layers consist of a refractory metal or alloy selected from the group consisiting of tungsten, titanium and alloys thereof. The compact may particularly have a roof or pentagonal shape. An intermediate transition film may be located between the refractory metal or alloy and the CBN blade.
Claims9
A flat cutting element for a drill, comprising a central abrading blade consisting of a sintered cubic boron nitride compact having a cubic boron nitride content higher than 80% vol. sandwiched between a pair of lateral support layers composed of a refractory metal selected from the group consisting of tungsten, titanium and alloys thereof and having a metallurgical bond with the blade, the sum of the thicknesses of the lateral layers being in a ratio of from 1:1 to 2:1 with the thickness of the blade.
A process for manufacturing a cutting element having a sandwich structure, comprising the steps of:
- successively placing, in a cup, a first layer of a refractory metal selected from the group consisting of tungsten, titanium and alloys thereof in powder or strip form, a layer of cubic boron nitride grains and catalytic binder, the amount of the CBN being of at least 80% vol. of the CBN-binder layer, and a second layer of said refractory metal in powder or strip form;
- sealing the cup;
- and
- subjecting the cup containing said layers to temperature and pressure conditions at which cubic boron nitride is in stable thermodynamic condition, for a sufficient time to cause sintering and intercrystalline bonding of the cubic boron nitride grains as a sintered compact.
Dependencies are inferred from the claim text.