RU2354534C2 - Mass for manufacture of abrasive tool - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention is related to the field of abrasive machining and may be used in manufacture of roughing tool for processing of grinding discs. Mass contains carbide-silicon grains and particles of abrasive fire-resistant filler, which is adhesively active to ceramic binder. Carbide silicon grains used are of isometric shape. Particles of abrasive fire-resistant filler are arranged with plate and needle shape. Content of main fractions of carbide-silicon grains and particles of abrasive fire-resistant filler in size makes at least 60%.

EFFECT: mass has even distribution of abrasive grains with increased strength of binding bridges and fixation of abrasive grains, which helps to increase tool quality, to reduce height difference in profile of working surface and its unbalance.

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Description

The invention relates to the production of abrasive tools, in particular peeling tools for processing grinding wheels.

Known mass for the manufacture of abrasive tools on a ceramic bond, containing a mixture of silicon carbide grains of at least two adjacent grit and filler particles made of adhesive-active material to a ceramic bond (see the description of the invention to patent RU 2262434 C1, CL B24D 3/14, October 20, 2005 Bull. No. 29). This mass allows you to create an abrasive tool with improved quality in strength and higher productivity. This mass for the manufacture of abrasive tools is taken as a prototype.

The disadvantage of the prototype is that when using silicon carbide grains and filler particles, classified only by size with the content of the main fraction within 45 ÷ 55%, an inhomogeneous mass is obtained. This is due to the presence in the mass of this number of grain size of various fractions of grains in size from extremely large to small. When mixing such a mass, small grains move faster than large grains. Therefore, there is a chance of their collision and the formation of a conglomerate of two or more large particles. This leads to the formation in the volume of the instrument of local foci of increased density and the heterogeneous distribution of the hardness of the shard of the instrument. At the same time, an uneven distribution of abrasive grains per unit area and their high different heights due to the difference in their sizes will be observed on the working surface of the tool. All this increases the imbalance of the tool, reduces the quality of the grinding surfaces of the products and the productivity of the processing process. In addition, the use of filler particles that have not been classified by shape reduces the quality of the tool in terms of strength, since disperse hardening of a composite material, such as a shard of a tool, is more effective in cases of using longitudinal flat and needle-like filler particles (see F. Matthews, R. Rawlings Composite materials. Mechanics and technology. M.: Technosphere, 2004).

The present invention solves the problem of eliminating these disadvantages of the prototype through the use of silicon carbide grains of isometric shape, and electrocorundum particles of lamellar and needle-shaped filler with a content of their main fractions of at least 60% in size. The use of isometric grains with a high content of their main fraction contributes to a more uniform and uniform distribution of grains both in the volume and on the working surface of the tool. In addition, isometric grains have greater strength than conventional intermediate grains, which will increase tool life and productivity. Simultaneously with the use of lamellar and needle-shaped filler particles, the tool strength is increased due to better reinforcement of the ligament bridges and, in general, the tool shard.

The solution to this problem allows you to achieve the following technical result - to improve the quality of the tool and its productivity, the mechanical strength of the crock and the strength of the abrasive grains in the bond, to reduce the different height profile of the working surface of the tool, imbalance or imbalance of the tool.

The goal is achieved by the fact that in the mass for the manufacture of an abrasive tool, silicon carbide grains are taken in isometric shape, and the filler particles are made in a plate and needle shape, while the content of the main fractions of grains and particles in size is at least 60%.

The use of abrasive grains of an isometric shape with a content of the main fraction of at least 60% allows to obtain uniform mixing of the abrasive mass, to ensure uniformity of the structure of the tool during its manufacture, to reduce the imbalance or imbalance of the tool. In addition, the use of isometric grains with a high content of the main fraction makes it possible to increase the pore space between grains on the working surface of the tool during dressing and during grinding by removing from the working surface some grains that are larger than conventional tools. This increases the average probability distance between the grains and at the same time decreases the height difference in the profile of the working surface of the tool, which will increase productivity and grinding quality. The choice of lamellar and needle-shaped filler particles with a high content of the main fraction makes it possible to increase the degree of reinforcement of the bridges of the bond between the abrasive grains and increase the overall mechanical strength of the tool and, as a result, increase the tool life and productivity. Thus, the proposed mass allows you to create an abrasive tool with improved quality in strength and higher productivity.

An abrasive tool from the proposed mixture is prepared in a known manner by mixing grains of silicon carbide and particles of electrocorundum filler, followed by the introduction of a ceramic binder, dextrin and water. From the finished mass, preforms of the abrasive tool are formed and their heat treatment is carried out at 1250 ° C.

The table shows comparative test data of tools made of abrasive mass according to the prototype and the proposed mass.

Abrasive tool made from mass The strength of the "eight" on the gap, MPa Grinding coefficient Resistance to products, pcs. prototype 6.9 9.2 76 proposed 7.8 12.3 92

An analysis of the results presented in the table shows that an abrasive tool made from the proposed mass has a tensile strength of "Eight" of 1.13 times, a grinding coefficient of 1.34 times and a resistance of 1.21 times higher than the corresponding figures for the tool prototype.

Claims (1)

A mass for the manufacture of an abrasive tool, containing silicon carbide grains and particles of an abrasive refractory filler, adhesive-active to a ceramic bond, characterized in that the silicon carbide grains are used in isometric form, and the particles of abrasive refractory filler are made in a plate and needle shape, while the content of the main fractions of carbide and particles of abrasive refractory filler in size is not less than 60%.