Process for producing automatic lubricating material for instruments

Abstract

A method for manufacturing a self-lubricating tool material which comprises grinding, mixing, pressing and sintering, wherein a mixture of a solid lubricant and a high-melting compound is previously prepared by mixing the solid lubricant with the high-melting compound, said components being capable of being ground simultaneously, and the prepared mixture is mixed with a powdered tool steel in the following proportions of components, in % by weight: - the solid lubricant 0.15 to 1 - the high-melting compound 5 to 30 - the powdered tool steel the remainder, wherein at least one compound selected from a group comprising hexagonal boron nitride, molybdenum disulfide, tungsten disulfide is used as the solid lubricant, while at least one compound selected from a group comprising carbides, nitrides, borides, oxides, except hexagonal boron nitride, is used as the high-melting compound.

Description

Title of the invention: Method for producing automatic lubricating material for instruments FIELD OF THE INVENTION

[0001] The invention relates to powder metallurgy, in particular, to methods of manufacturing a self-lubricating tool material, and can be used in the manufacture of wear-resistant tools and parts. Prior art

[0002] A method of manufacturing a tool material is known, the method comprises grinding, mixing, pressing and sintering (USSR Author's Certificate for an invention No. SU 1280908 "Sintered composite material based on tool steel" of 1985, IPC C22C 33 / 02).

[0003] A disadvantage of the described method is that agglomerates of aggregated particles of a high-melting compound are formed in the method during the preparation of a mixture of components, i.e. the components of the mixture are not distributed uniformly, and separate melted zones, shrinkage holes, loosening are formed in the material during subsequent sintering.

[0004] As a result, a tool material which is manufactured using the known method has a non-uniform structure and a high coefficient of friction, which generally decreases the wear resistance properties and degrades the tribotechnical and operational properties of the manufactured material. Summary of the invention

[0005] A technical objective of the claimed invention is to provide a method of manufacturing a self-lubricating tool material which could make it possible, by using the method, to increase the wear resistance properties and to improve the tribotechnical and operational properties of the material manufactured according to the present method.

[0006] The technical objective is achieved by a method for manufacturing a self-lubricating tool material which comprises grinding, mixing, pressing and sintering, wherein, according to the invention, a mixture of a solid lubricant and a high-melting compound is prepared by mixing the solid lubricant with the high-melting compound, said compounds being capable of being ground simultaneously, and the prepared mixture is mixed with a powdered tool steel in the following proportions of the compounds, in wt.%:

[0007] - solid lubricant - 0.15 to 1;

[0008] - the high melting point compound - 5 to 30;

[0009] - powdered tool steel - the rest,

[0010] wherein at least one compound selected from a group comprising hexagonal boron nitride, molybdenum disulfide, tungsten disulfide is used as a solid lubricant, while at least one compound selected from a group comprising carbides, nitrides, borides, oxides, with the exception of hexagonal boron nitride, is used as a high melting point compound.

[0011] During the preliminary preparation of the mixture of the solid lubricant and the high-melting compound by mixing the solid lubricant with the high-melting compound, said components being capable of being ground simultaneously, particles of the high-melting compound are enveloped by particles of the solid lubricant, which reduces the aggregation of the particles, simplifies and increases the efficiency of a void-filling process, which upon further mixing with the powdered tool steel leads to a uniform distribution of the particles of the high-melting compound and the solid lubricant within the material structure, as a result of which the material manufactured by this method has the uniform structure, its friction coefficient is reduced, and the tribotechnical, wear-resistant and operational properties are generally improved.

[0012] At the same time, the ability to grind the high melting point compound and the solid lubricant simultaneously with the mixing allows uniformity to be achieved and the coefficient of friction of the material to be reduced more quickly due to an increase in the number and specific surface area of the particles of the high melting point compound and the solid lubricant to provide more effective lubrication.

[0013] An addition of the solid lubricant in the amount of less than 0.15% by weight is not sufficient to lubricate the particles of the high-melting compound, while the addition of the solid lubricant in the amount of more than 1% by weight does not lead to a further reduction of the coefficient of friction, and an excess amount of the lubricant reduces the mechanical properties of the material (in particular, the rigidity) which results in a degradation of the tribotechnical, wear-resistant and operational properties of the material in general.

[0014] An addition of the high melting point compound in the amount of less than 5 wt% leads to the non-uniform distribution of the insufficient number of the particles of the high melting point compound in the excess amount of the solid lubricant, the mixture and the material which is eventually made therefrom become non-uniform, the wear resistance of the material is generally decreased, whereas the addition of the high melting point compound in the amount of more than 30 wt% leads to a condition, when the lubricant becomes insufficient to lubricate the increased number of the particles of the high melting point compound which prevents the reduction of the friction coefficient, the distribution of the particles in the mixture becomes non-uniform which results in a degradation of the tribotechnical properties, wear resistance and operational properties of the final material in general.

[0015] At least one compound selected from the group comprising hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, but without any limitation, is used as a solid lubricant, since these particular compounds exhibit the greatest lubricating properties in combination with the high melting point compound, at least one compound selected from a group comprising carbides, nitrides, borides, oxides, except hexagonal boron nitride, being used as the high melting point compound.

[0016] In particular, the latter compounds exhibit optimal properties with respect to steel, namely high rigidity, do not change their properties during sintering, and have good sintering with steel.

[0017] Thus, the use of the claimed method for the manufacture of the self-lubricating tool material makes it possible to increase the wear resistance properties and to improve the tribotechnical and operational properties of the material manufactured according to the present method.

[0018] EMBODIMENTS OF THE INVENTION

[0019] The invention will be explained below by a detailed description of its specific embodiment given by way of example.

[0020] The powdered steel is ground in a continuously operating jet mill.

[0021] A powdered titanium carbide, taken as a high melting point compound which is selected from the group comprising carbides, nitrides, borides, oxides, is ground in a vibration mill.

[0022] The ground powdered steel is supplemented with a mixture which is previously prepared by mixing 0.6% by weight of molybdenum disulfide taken as a solid lubricant which is preferably chosen from the group which comprises hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, and 20% by weight of the ground titanium carbide taken as a high melting point compound which is chosen from the group which comprises carbides, nitrides, borides, oxides, with the exception of hexagonal boron nitride.

[0023] Preliminary stirring of molybdenum disulfide taken as a solid lubricant with titanium carbide taken as a high-melting compound leads to the fact that due to the preliminary distribution of molybdenum disulfide in titanium carbide, the latter is provided with plastic and mobility properties.

[0024] As an example, it is possible to grind titanium carbide and molybdenum disulfide, while stirring them simultaneously. With this, the number of titanium carbide and molybdenum disulfide particles is increased and, thus, their specific surface area is increased, and, for this reason, making the lubricating surface is increased, which strengthens and accelerates the lubrication of the titanium carbide by the molybdenum disulfide.

[0025] For this reason, upon further addition of this previously prepared mixture to the powdered steel, agglomeration of the particles of the mixed materials is avoided, the distribution of the mixture between the particles of the steel component is improved, which makes it possible to obtain a more uniform structure of the material, to reduce the coefficient of friction, and, thus, to strengthen the tribotechnical properties of the material.

[0026] Then, the mixture thus obtained is loaded into capsules which are sealed.

[0027] Then, as an example, the capsules are sintered in an isostatic press at a pressure of 160 MPa at a temperature of 1140°C for 1.5 hours.

[0028] As another example, the capsules are heated to a temperature of 1130°C (sintered) after sealing and hot pressing (extruded) on a hot extrusion press with a degree of deformation of 90%.

[0029] Then, the obtained composite material is removed from the capsules.

[0030] The self-lubricating tool material manufactured according to the claimed method has the uniform structure and the low coefficient of friction which provide, during the manufacture of tools and parts, a reduction of wear, a reduction of heating of the tool and its softening, an extension of the service life of the tool and parts.

[0031] Generally, the use of the claimed method for the manufacture of the self-lubricating tool material makes it possible to increase the wear resistance properties and to improve the tribotechnical and operational properties of the material manufactured according to the present method.

[0032] The claimed method for manufacturing the self-lubricating tool material is efficient in use and can be used to a wide extent in industry in the manufacture of wear-resistant tools and parts, in particular, cutting, stamping and forming tools and parts for machine engineering.

Claims

[Claim 1] Claims A method of manufacturing a self-lubricating tool material which comprises grinding, mixing, pressing and sintering, wherein a mixture of a solid lubricant and a high-melting compound is previously prepared by mixing the solid lubricant with the high-melting compound, said components being capable of being ground simultaneously or separately, and the prepared mixture is mixed with a powdered tool steel in the following proportions of the components, in % by weight: - solid lubricant 0.15 to 1 - high melting point compound 5 to 30 - powdered tool steel the rest, wherein at least one compound selected from a group comprising hexagonal boron nitride, molybdenum disulfide, tungsten disulfide is used as a solid lubricant, while at least one compound selected from a group comprising carbides, nitrides, borides, oxides, except hexagonal boron nitride, is used as a high melting point compound.