초록 ▼

A method of thermally treating a preform element, of the kind having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, comprises the steps of: (a) heating the element to a soaking temperature of 550-625° C., and preferably about 600° C., (b) maintaining th

A method of thermally treating a preform element, of the kind having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, comprises the steps of: (a) heating the element to a soaking temperature of 550-625° C., and preferably about 600° C., (b) maintaining the element at that temperature for at least one hour, and (c) cooling the element to ambient temperature. The resulting preform element has a substrate with a cobalt binder including a substrate interface zone with at least 30 percent by volume of the cobalt binder a hexagonal close packed crystal structure. This reduces the risk of cracking or delamination of the element in use.

대표청구항 ▼

1. A method of treating a preform element having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, the method comprising the steps of: (a) heating the element to a soaking temperature in the range of 550-700° C., (b) maintaining the temperature of the

1. A method of treating a preform element having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, the method comprising the steps of: (a) heating the element to a soaking temperature in the range of 550-700° C., (b) maintaining the temperature of the element in said range for a period of at least eighteen hours, and (c) cooling the element to ambient temperature. 2. A method according to claim 1 wherein, in the heating step (a), the temperature of the element is raised to the soaking temperature, for a period in the range of one half to one and a half hours. 3. A method according to claim 1, wherein, in step (a), the temperature of the element is raised to a value in the range of 550-625° C. 4. A method according to claim 1, wherein, in step (a), the temperature of the element is raised to a value in the range of 575-620° C. 5. A method according to claim 1, wherein, in step (a), the temperature of the element is raised to about 600° C. 6. A method according claim 1, wherein the facing table of the preform element has a substantially flat front face, a peripheral surface, and a rear surface bonded to a front surface of the substrate. 7. A method according to claim 1, wherein the facing table of the preform element has a domed front face, and a rear surface bonded to a domed front surface of the substrate. 8. A method according to claim 6, where the facing table of the preform element comprises a plurality of layers of polycrystalline diamond. 9. A method according to claim 1, wherein at least steps (a) and (b) are effected in a non-oxidizing atmosphere. 10. A method according to claim 1, wherein in step (b) the temperature of the element is maintained for a period of at least thirty-six hours in a non-oxidizing atmosphere.