RU2507057C1 - Polygranular mass for production of structured abrasive tool - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of abrasive tools of ceramic binders with fine-count-structures. Abrasive mass comprises the mix of grains of three groups: first group is composed of the grain sized to 160-420 mcm, second group is composed the grain sized to 120-159 mcm and third group is composed the grain sized to 90-119 mcm. Note here that total volume content of the first two groups corresponds to volume content of abrasive for preset count of abrasive tool structure while that of the third group makes 5-15% of the first group grain volume content. Filler consists of the mix of pit particles sized to 250-800 mcm in amount of 15% of abrasive mass volume. Invention allows decreasing the volume strain ay high-temperature tool sintering. Application of minor fineness of equal-density grains with working abrasive grains allows more homogeneous mixing of abrasive mass for producing more homogeneous volume structure.

EFFECT: increased quantity of solid crystallisation centres of fused ceramic binder at its cooling with formation of strong chemical bond.

2 cl, 1 tbl, 8 ex

Description

The invention relates to the production of abrasive tools on ceramic bonds with high structure numbers.

The prior art mass for the manufacture of highly porous abrasive tools containing heat-resistant filler in the form of hollow spherical particles of electrocorundum, and the magnitude of the spherical particles is 0.45-0.65 of the size of the abrasive grains with a content of the last 30-37 vol.% (Copyright certificate No. 1073082, B24D 3/14, 1984)

The main disadvantage of abrasive tools made from this composition is that increased porosity is achieved by increasing the content of heat-resistant spherical filler, which, in turn, reduces the hardness of the abrasive tool. This leads to increased tool wear during forced processing.

The closest solution in technical essence and the achieved result is a mass for the manufacture of an abrasive tool, including an abrasive, a ceramic bond and a filler in the form of hollow spherical particles of aluminosilicate in the form of a mixture of particles ranging in size from 5 to 560 μm in an amount of 2-200 vol.% Abrasive. Additionally, the mass may contain a burnable filler in an amount of 5-250% by volume of an aluminosilicate filler and a filler in the form of hollow spherical particles of low-melting glass in an amount of 5-100% by volume of an aluminosilicate filler both individually and in a mixture of two fillers with a total content of 5 to 250% of the volume content of aluminosilicate filler (see RF Patent No. 2152298, B24D 3/18, 2000)

The results of a study of the manufacturability of grinding wheels based on white aluminum oxide and green silicon carbide found that the use of abrasive compositions in a known technical solution is advisable only for the production of tools with structure numbers up to 12, that is, with a volumetric abrasive content of at least 38%. In the manufacture of an abrasive tool with higher structure numbers, its volumetric deformation (shrinkage) after high-temperature firing reaches critical values at which the prerequisites for the appearance of cracks and possible destruction of grinding wheels are created (Stark V.K. “Grinding with highly porous wheels”, M., Mechanical Engineering , 2007, p. 207). By increasing the structure number of the instrument to 22, the volumetric deformation of the instrument made using a filler in the form of hollow spherical particles of aluminosilicate and low-melting glass in a mixture with a burnt filler in the form of ground fruit seeds according to the prototype can reach 38.1% (Stark V.K. Grinding with highly porous circles ”, M., Mechanical Engineering, 2007, p. 208).

To increase the structure number of the abrasive tool or its structure, it is necessary to reduce the volume content of the abrasive in the mass for its manufacture. To reduce the increasing deformation of the abrasive tool while reducing the abrasive content in it, it is necessary to compensate for its absence by the additional introduction of fillers.

As the filler can be used, for example, corundum, aluminosilicate and glass hollow spherical particles, ground fruit seeds (see RF Patent No. 2152298, B24D 3/18, 2000) or naphthalene (see Stark V.K. “Grinding highly porous circles ", M, Engineering, 2007, p. 48).

The disadvantage of grinding wheels made of abrasive mass with the introduction of two or more of these fillers is the inability to produce a homogeneous mass due to the significant heterogeneity of the components introduced into it. The density range of the components of the abrasive mass, for example, based on white electrocorundum on a ceramic bond, is 3.95 g / cm3 for grain, 2.5 g / cm3 bond, 1.5 g / cm3 fruit seed and 0.4- hollow spherical particles 0.7 g / cm3, that is, the different density can fluctuate almost 10 times.

The heterogeneity of the formed abrasive mass during its preparation by mixing results in increased instability of hardness in the volume of the tool and a spread in the values of its mass imbalance.

The main disadvantage of an abrasive tool made using a burnable filler and a filler in the form of hollow spherical particles of corundum, aluminosilicate and glass is its increased deformation (shrinkage) during drying and high temperature sintering.

The technical result of the claimed technical solution is to reduce volumetric deformation during high-temperature sintering of the tool.

The essence of the invention lies in the fact that the polymeric mass for the manufacture of highly structural abrasive tools, including abrasive, ceramic bond, adhesive and moisturizing additives and filler, according to the invention, consists of a mixture of grains of three groups, the first group of grains with sizes ranging from 160-420 microns; the second - grains with a size in the range of 120-159 microns; the third - grains with sizes ranging from 50-119 microns, while the total volumetric content of the first two groups corresponds to the volumetric abrasive content for a given structure number of the abrasive tool, and the volumetric grain content of the third group is 5-15% of the volumetric grain content of the first group, and the filler is a mixture of particles of fruit seeds with sizes in the range of 250-800 microns in the amount of 5-15% of the volume of abrasive mass.

Optimally, the filler is made in the form of a mixture of hollow spherical particles of aluminosilicate with a size in the range from 85 to 560 microns in an amount of 20-50% vol. more abrasive grit.

An additional introduction to the mass of abrasive grains with a small size relative to the other two grains does not affect the cutting ability of the tool. They practically do not participate in the process of removing the processed material, which is provided by abrasive grains on the working surface of the tool with sizes 2-8 times larger than grains of the third grain size.

The advantage of a polysulphuric mass consisting of three groups of grains with different sizes is the increased role of abrasive grains in improving the manufacturability of tool manufacturing. The use of finer grain size grain with the same density with working abrasive grains provides a more uniform mixing of the polysulphuric mass with the formation of a more uniform bulk structure. The number of solid crystallization centers of the molten ceramic binder also increases as it cools to form a strong chemical bond “grain-binder”.

Examples of the use of the claimed polysulphurous mass are given below.

Example 1

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with a size of 120 μm (grain size) F100 and 100 μm (grain size F120) with a structure of N = 16 consists of the following components,% vol .:

Grade 25A abrasive grain with a size of 160 microns (grain size F80) - 28 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 2 The total grain content with a size of 160 μm (grain size F80) and grain size of 120 μm (grain size F100) - thirty Abrasive grain grade 25A with a size of 100 microns (grit F120) - 1.4 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 5% Ceramic bond K5C - 8

Fruit bone KF25 with a size of 250 microns (filler) - 5 Adhesive and moisturizing additives - 22

Example 2

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 18 consists of the following components,% vol .:

Grade 25A abrasive grain with a size of 160 microns (grain size F80) - 22 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - four The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - 26 Abrasive grain grade 25A with a size of 100 microns (grit F120) -1.8 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 8.2% Ceramic bond K5C - 8.5 Fruit pit KF40 with a size of 400 microns (filler) - 8 Adhesive and moisturizing additives - 23

Example 3

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 20 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) - 19 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 3 The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - 22 Abrasive grain grade 25A with a size of 100 microns (grit F120) - 2.1 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 11.05% Ceramic bond K5C - 9 Fruit stone KF63 with a size of 630 microns (filler) - eleven Adhesive and moisturizing additives - 24

Example 4

The granular mass for the manufacture of grinding wheel from white alumina grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 22 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) - 16 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 2 The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - eighteen Abrasive grain grade 25A with a size of 100 microns (grit F120) - 2.4 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - fifteen% Ceramic bond K5C - 9.5 Fruit pit KF80 with a size of 800 microns (filler) - fifteen Adhesive and moisturizing additives - 25

A disadvantage of grinding wheels made on the basis of an abrasive mass containing hollow spherical particles of aluminosilicate in the form of a mixture of particles with sizes from 5 to 560 microns, is also that it contains 20-29% aluminosilicate particles with sizes from 5 to 84 microns . These small-sized particles of aluminosilicate due to the absence of an internal cavity in them have a higher density in comparison with larger aluminosilicate particles, are prone to segregation during the preparation (mixing) of the abrasive mass, during high-temperature roasting of the tool they do not melt and migrate through the liquid bundle under the action of force gravity to the bottom surface of the tool mounted on the pallet. For these reasons, the introduction of aluminosilicate particles from 5 to 84 μm into the abrasive mass negatively affects the stability of hardness in the volume of the tool and contributes to the formation of increased values of its mass imbalance (imbalance).

Technically, it is not difficult to remove from the finished product in the form of aluminosilicate particles from 5 to 560 μm in size its fine fraction from 5 to 84 μm in size by additional sieving.

If you use aluminosilicate hollow spherical particles ranging in size from 85 to 560 microns in an amount of 20-50% of the volume content of abrasive grains with the highest grain size as an additional filler, the efficiency of manufacturing highly structured circles with structure numbers from 16 to 22 increases.

Possible examples of the compositions of the abrasive mass with the additional introduction of a filler in the form of aluminosilicate hollow spherical particles ranging in size from 85 to 560 μm are described below.

Example 5

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 16 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) - 28 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 2 The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - thirty Abrasive grain grade 25A with a size of 100 microns (grit F120) - 1.4 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 5% Ceramic bond K5C - 8 Aluminosilicate hollow spherical particles (filler) in the form of a mixture of particles with sizes from 85 to 560 microns - 5.6 The relative content of aluminosilicate hollow spherical particles to the content of abrasive grain 25A with a size of 160 μm (grain size F80) - twenty% Adhesive and moisturizing additives - 22

Example 6

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 18 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) - 22 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - four The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - 26

Abrasive grain grade 25A with a size of 100 microns (grit F120) - 1.8 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 8.2% Ceramic bond K5C - 8.5 Aluminosilicate hollow spherical particles (filler) in the form of a mixture of particles with sizes from 85 to 560 microns - 6.5 The relative content of aluminosilicate hollow spherical particles to the content of abrasive grain 25A with a size of 160 μm (grain size F80) - 29.8% Adhesive and moisturizing additives - 23

Example 7

The granular mass for the manufacture of grinding wheel from white aluminum oxide grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 20 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) -19 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 3 The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - 22 Abrasive grain grade 25A with a size of 100 microns (grit F120) - 2.1 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - 11.05% Ceramic bond K5C - 9 Aluminosilicate hollow spherical particles (filler) in the form of a mixture of particles with sizes from 85 to 560 microns - 7 The relative content of aluminosilicate hollow spherical particles to the content of abrasive grain 25A with a size of 160 μm (grain size F80) - 36.8% Adhesive and moisturizing additives - 24

Example 8

The granular mass for the manufacture of grinding wheel from white alumina grade 25A with a size of 160 μm (grain size F80) and with dimensions of 120 μm (grain size F100) and 100 μm (grain size F120) with a structure of N = 22 consists of the following components,% vol .:

Abrasive grain grade 25A with a size of 160 microns (grain size F80) - 16 Abrasive grain grade 25A with a size of 120 microns (grain size F100) - 2 The total content of grain with a size of 160 μm (grit F80) and grain with a size of 120 μm (grit F100) - eighteen Abrasive grain grade 25A with a size of 100 microns (grit F120) - 2.4 Relative grain content with a size of 100 μm (grit F120) to the grain content with a size of 160 μm (grit F80) - fifteen% Ceramic bond K5C - 9.5 Aluminosilicate hollow spherical particles (filler) in the form of a mixture of particles with sizes from 85 to 560 microns - 8 The relative content of aluminosilicate hollow spherical particles to the content of abrasive grain with a size of 160 μm (grain size F80) - fifty% Adhesive and moisturizing additives - 25

For experimental verification of the proposed technical solutions, 8 masses were made for laboratory samples and grinding wheels in accordance with the examples presented above.

The properties of abrasive masses according to examples 1-8 were studied on special samples.

To determine the volumetric strain after firing, dies with a diameter of 80 mm and a height of 20 mm were used. Volumetric deformation of the samples was established by the difference in sample volumes before and after firing.

The table shows the results of measuring volumetric deformation on samples made from 8 declared masses and abrasive masses according to the prototype.

In all cases, the results for the declared masses were better than for samples from the masses of the prototype.

Table Granular mass for the manufacture of highly structural abrasive tools No. Volumetric strain,% Declared mass The mass of the prototype one 3.93 6.82 2 4.98 3 6.41 four 8.0 5 3.62 6 4.79 7 5.92 38.1 8 7.73

Thus, the claimed combination of features set forth in the claims allows, in comparison with the prototype, to provide a reduction in volumetric deformation during high-temperature sintering of the tool ..

The analysis of the claimed technical solution for compliance with the conditions of patentability showed that the characteristics indicated in the independent claim are interrelated with each other with the formation of a stable set of necessary attributes unknown at the priority date from the prior art sufficient to obtain the required synergistic (over-total) technical result.

The properties regulated in the claimed compound by individual features are well known in the art and do not require further explanation.

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed technical solution:

- the object embodying the claimed technical solution, in its implementation is intended for the manufacture of grinding wheels;

- for the claimed object in the form described in the independent claim, the possibility of its implementation using the means and methods known from the prior art on the priority date on the priority date has been confirmed;

- the object embodying the claimed technical solution, when implemented, is able to ensure the achievement of the technical result perceived by the applicant.

Therefore, the claimed subject matter meets the requirements of patentability “novelty”, “inventive step” and “industrial applicability” under applicable law.

Claims (2)

1. A granular mass for the manufacture of a highly structural abrasive tool, including an abrasive, a ceramic bond, adhesive and moisturizing additives and a filler, characterized in that the abrasive consists of a mixture of grains of three groups, the first group of grains ranging in size from 160-420 microns, the second - grain size in the range of 120-159 μm, and the third grain size in the range of 50-119 μm, while the total volume content of the first two groups corresponds to the volume content of the abrasive for a given structure number of the abrasive tool, and about the bulk content of grains of the third group is 5-15% of the volumetric content of grains of the first group, the filler is a mixture of particles of fruit seeds with sizes in the range of 250-800 microns in an amount of 5-15% of the volume of abrasive mass. 2. The granular mass according to claim 1, characterized in that it further comprises a filler in the form of a mixture of hollow spherical particles of aluminosilicate with a size in the range from 85 to 560 μm in an amount of 20-50 vol.% Abrasive with a larger grain size.