CS253169B1 - Powder mixture - Google Patents

Abstract

The solution relates to the field of powder metallurgy, where it solves the powder mixture for creating a connection between a steel sleeve and a polycrystalline diamond core in a hard metal sleeve, respectively a steel sleeve and a diamond core. The essence of the solution is that the powder mixture contains 30 to 50% by mass. iron, 2 to 15 wt.% iron silicide, 40 to 60 wt.% copper and 2 to 10 wt.% tin.

Description

The invention relates to a powder mixture for forming a connection between a steel sleeve and a polycrystalline diamond core in a carbide sleeve respectively a steel sleeve and a diamond core.

The most common connection between the steel sleeve and the die core itself is formed by placing a polycrystalline or monocrystalline diamond core in or without the carbide sleeve in the steel sleeve and sprinkling with a pre-homogenized powder mixture.

The set thus prepared is heat-treated - usually heated under external pressure. This results in diffusion processes resulting in sufficient fixation of the core in the steel sleeve. At the end of this operation, the inlet cone in the sintered surrogate is drilled from the powder mixture. To date, in particular, a combination of powdered copper and tin is used as the powder mixture for the intermediate sleeve material. It is also known to use a mixture of tungsten carbide and cobalt or a combination of cobalt and copper.

The current situation shows a number of shortcomings. When using a copper-tin CuSn solder, the operation of the solder, in particular during the heat-up of the entire die, results in the erosion of the solder, which melts the parts bordering the die core and eventually releases the entire core. The tungsten carbide-cobalt WC-Co mixture requires a high sintering temperature which leads to graphitization of the diamond polycrystalline die core itself. Other prior art compositions used as interlayer material have a different coefficient of thermal expansion, which results in undesirable cracks in the diamond core due to the stresses.

These drawbacks are eliminated by the powder mixture for forming the bond between the steel sleeve and the polycrystalline diamond core in the carbide sleeve respectively the steel sleeve and the diamond core of the present invention, which comprises 30 to 50 wt. % Fe, 2 to 15 wt. % FeSi iron silicide, 40 to 50 wt. % copper Cu and 2 to 10 wt. Tin Sn.

The basic advantage of this material is a sufficiently low sintering temperature, good mechanical properties such as impact and flexural strength and in particular a favorable coefficient of thermal expansion.

Example 1

A die with or without a polycrystalline diamond core in or without a carbide sleeve requires a powder mixture for the intermediate sleeve of the following composition. 40% iron Fe, 5% iron silicide FeSi, 49% copper Cu, 6% tin Sn.

Example 2

The die with the diamond single crystal core without treatment or pre-plated requires a powder mixture for the intermediate sleeve of the following composition. 46% iron Fe, 3% iron silicide FeSi, 46% copper, Cu, 6% Sn. Application of the inter-mixture mixture resulted in an increase in thermal and chemical erosion resistance of up to 30%.

Claims (1)

PftEASE OF THE INVENTION Powder mixture for forming a connection between a steel sleeve and a polycrystalline diamond core in a carbide sleeve and a steel sleeve and a diamond core, respectively, characterized in that it contains 30 to 50% by weight of a steel sleeve. Fe 2 to 15 wt. % FeSi iron silicide, 40 to 60 wt. % copper Cu and 2 to 10 wt. Tin Sn.