RU2043870C1 - Hard alloy tools production method - Google Patents

Abstract

FIELD: powder metallurgy. SUBSTANCE: method to produce hard alloy tools production provides for mixing of carbides, blast pressing and following impregnation of blank with alloy-binder. In the case, after blast pressing blank is sintered and impregnation is exercised after sintering, and cobalt is used as alloy-binder. EFFECT: increased efficiency of hard alloy tools production.

Description

 The invention relates to mechanical engineering production, in particular to the manufacture of carbide cutting inserts for cutters, milling cutters, countersinks, drills.

A known method of manufacturing a carbide tool, comprising mixing carbides of titanium, tungsten and tantalum with cobalt as a binder. The resulting mixture is subjected to mechanical pressing at low pressure, and then sintered [1]
However, mechanical pressing does not provide a strong bond between carbide grains. To this end, the proposed technical solution uses shock wave compression, in which carbide grains are crushed to form bonds between them on developed contact and exposed juvenile surfaces, which gives the pressing the strength of bond bridges.

 A known method of producing high-density compacts [2] in which shock wave pressing is also used. However, it is combined with exothermic sintering, which is achieved by mixing compactable powders with exothermic additives, for example Ti-C, Ti-Al.

 An exothermic reaction, starting on one edge of the compact, does not ensure its uniform heating, resulting in areas with uneven hardness and insufficiently strong bridges of the bundle. Due to uneven volumetric diffusion, microcracks can occur, leading to a decrease in compressive strength.

 In order to increase the strength and cutting ability of the carbide tool in the proposed method, after impact pressing, sintering is carried out in a furnace, which ensures uniform heating of the pressing and its further hardening. The introduction of liquid cobalt after sintering provides high hardness and compressive strength.

 A method of manufacturing a carbide tool includes mixing carbide components: tungsten carbides, titanium carbides, tantalum carbide, etc. in proportions corresponding to the obtained grade of hard alloy. So, for example, to obtain a T5K10 grade alloy, 1 part (mass) of titanium carbide is mixed with 17 parts (mass) of tungsten carbide. Then, the thoroughly mixed mixture is poured into a mold, the shape of the cavity of which corresponds to the shape of the plate, and is subjected to compression by shock waves in an electro-hydraulic installation. The energy developed as a result of pressing reaches 20-60 kJ.

After pressing, the compact is removed from the mold and placed in an electric vacuum sintering furnace at a temperature equal to 0.8 of the lowest melting temperature of the carbide component. Sintering is carried out for 1-3 hours. After cooling the furnace and removing the carbide blanks, the latter are placed in heat-resistant baths (crucibles, pallets, etc.), cobalt plates are superimposed on them based on the proportions corresponding to the manufactured alloy grade. For example, to obtain a T5K10 grade plate for one mass part of titanium carbide, which is part of the workpiece, it is necessary to take two mass parts of cobalt. Blanks and cobalt again placed in the electric vacuum furnace, the contents are heated to the melting point of cobalt ^(about 1494 C) and maintained at this temperature for one hour, then the furnace heating is turned off, the oven and the contents cooled and the finished tool is removed from the furnace.

PRI me R. Braley powder tungsten carbide (79 wt.) Was mixed with titanium carbide powder (15 wt.), Was compressed by a shock wave to the electro installation type "kick" and sintered in an electric vacuum furnace at 1600 ^C for 2 hours. Then the impregnated liquid cobalt at 1500 ^C for 3 hours. The resulting plate had predelnodopuskaemoe bending stress 1600 MPa, 5200 MPa compressive hardness HRA of 95 units.

 The plate obtained by the proposed method was used for turning steels 40X, 4X5MFS, 3X3M3F, 12X18H10T. Processing of 12Kh18N10T steel was carried out under the following conditions: cutting speed 52 m / min, feed 0.15 mm / rev, cutting depth 1.0 mm. After 20 minutes of processing, wear at the tip of the cutter with a plate made by the proposed method was 0.15 mm, while the T15K6 alloy with a titanium nitride coating had a wear value of 0.2 mm.

 When turning 40X steel, the following cutting conditions were used: cutting speed 130 m / min; feed 0.2 mm / rev, cutting depth 1.0 mm. At the same time, wear at the tip of the cutter with a carbide insert manufactured by the proposed method, after 20 minutes of processing was 0.085 mm, while the cutter with a T15K6 plate coated with titanium nitride (when processing the same steel at the same cutting conditions) had wear at the apex of 0.13 mm.

 Turning of steel 4X5MFS was carried out under the following cutting conditions: cutting speed 130 m / min, feed 0.5 mm / rev, cutting depth 1.5 mm. After processing for 20 minutes, the wear at the tip of the cutter was: for a plate according to the proposed manufacturing method, 0.20 mm, for a T15K6 plate with a titanium nitride coating 0.24 mm.

 Turning of 333M3F steel was carried out under the following cutting conditions: cutting speed 105 m / min, feed 0.4 mm / rev, cutting depth 3 mm. Processing was carried out for 20 minutes. After that, wear at the tip of the cutter was determined. The wear of the carbide plate manufactured by the proposed method was 0.52 mm, while the wear of the T15K6 plate with a titanium nitride coating was 0.65 mm. Moreover, in the latter case, private chips of the cutting inserts were observed.

Claims (1)

 METHOD FOR PRODUCING A CARBIDE INSTALLATION TOOL, including carbide mixing, explosive pressing and subsequent impregnation of a workpiece with a binder alloy, characterized in that after explosive pressing, the workpiece is sintered, impregnated after sintering, and cobalt is used as a binder alloy.