Diamond-hard alloy macrocomposite material: Development and application

A new diamond-hard alloy macrocomposite material consisting of diamond grits (0.5–0.8 mm or more in size) and a WC-Co matrix has been developed. The material is characterized by high mechanical properties of the matrix (the same as for WC-Co monolithic hard alloys) while diamonds remain completely intact (no graphitization or dissolution in cobalt melt). This process does not require superhigh pressures. Hard-alloy samples sintered beforehand in conditions that ensure the maximum mechanical properties (1450–1500°C, 30–60 min holding) are used as initial materials. Hollows (cells) or ditches of specific sizes (depth, width) are made in these samples with mechanical or electrophysical methods, and then diamond crystals (grits) commensurate with the hollows, cells, or ditches are placed in them. Vacuum infiltration (brazing) at moderate temperatures (900–1150°C) with adhesion-active alloys (or metallized diamonds) is the final stage in the formation of the composite. Therefore, strong adhesion-mechanical fixation of diamond grits in the hard-alloy matrix is ensured. The new material is efficiently used in diamond bits.     

Blood parameter determination by conductometric hemolysis recording

Translated from Izmeritel'naya Tekhnika, No. 1, pp. 65–66, January, 1989.     

Improving the quality of layers deposited on rolling rolls by optimising the composition of flux-cored wires

ABSTRACT

Experiments were carried out to investigate the effect of adding carbon–fluorine compounds (the waste from metallurgical production) and nickel powder to the composition of flux-cored wires of the C–Si–Mn–Cr–W–V and C–Si–Mn–Cr–V–Mo alloying systems. The results show that the addition of these compounds to the composition of the charge for producing the wires of the 35V9Kh3SF and 25Kh5FMS types improves a large number of the characteristics of the deposited layer: reduces the extent of contamination with non-metallic inclusions, increases the hardness of the deposited layer, refines austenite grains and results in the formation of fine-dispersion carbides which in practice may improve the thermal resistance of rolling rolls, and also prevents the formation of a ferrite network which may have a beneficial effect on cracking resistance. The experimental results can be used to develop new compositions of flux-cored wires for hardfacing rolling rolls protected by Russian Federation patents. The hardfacing technologies of the rolls using these flux-cored wires with the C–Si–Mn–Cr–W and C–Si–Mn–Cr–V–Mo alloying systems are now produced by the ElSib company.     

Wear resistance of chromium-containing matrices of diamond drilling tools

The paper examines the wear rate in friction of copper-impregnated samples produced by pressing of VK6 powder with chromium additions. The test is conducted on a cast iron disk in the presence of a wet SiC powder and on a diamond wheel without cooling. It is shown that higher chromium content insignificantly increases the sample wear rate in friction with the cast iron disk. At the same time, the wear rate abruptly decreases for the diamond wheel. The hardness of the samples does not significantly change with increasing chromium content to 6 wt.%.