SU1248780A1 - Abrasive composition - Google Patents

Description

25

The invention relates to the abrasive industry and can be used in the manufacture of cut-off wheels on a bakelite link.

 The purpose of the invention is to increase the mechanical strength of an abrasive tool by introducing quartz with a particle size from 10 to 100 microns into the abrasive mass as a filler.

The offered abrasive. The mass contains grinding material, synthetic resin and fillers, in addition, in addition quartz with a particle size of 15 from 10 to 100 microns is introduced as a filler with the following ratio of components, wt.%:

Grinding material 67-84 Synthetic resin 11-16 Quartz1-7 20

FillersEverything

Quartz has a linear expansion coefficient ranging from 0, 510 to 3 10, degrees, which is an order of magnitude less than the linear expansion coefficient of the binder. Therefore, with its uniform distribution in the associated linear expansion coefficient, the binding decreases. In addition, the introduction of abrasive mass of quartz particles ranging in size from 10 to 100 µm contributes to the strengthening of the bridges of the bond. With an increase in the quartz size of more than 100 microns, the quartz particles appear. stress centers in conjunction with the difference between their linear expansion coefficient and the binder, which has a negative effect on the strength of the tool. When the quartz size is less than 10 µm, the hardening effect disappears. This is due to the fact that the polymer bond does not provide a uniform coating of quartz particles less than 10 µm. less myio strength than bond itself. In addition to reducing the stresses that occur in a circle during heat treatment and during subsequent cooling, quartz lowers the linear expansion coefficient of the tool itself as a whole. And when cutting metal, heated up to, the circle is heated through the end surfaces and stresses occur between the inner carrier and the outer cutting also.

thirty

35

40

45

50

55

five

50

five

0

0

five

0

five

These stresses are summed with the stresses caused by centrifugal forces, which leads to the separation of the parts of the circle in contact with the heated metal. The reduction in the linear expansion ratio of the abrasive wheel due to the introduction of quartz leads to an increase in the dynamic strength of the tool.

Quartz particles, having strength,. superior strength of the other bond, actively participate in its dispersion strengthening, stopping the growth of microcracks. With increases of more than 2000, many microcracks and defects are found in quartz crystals, which, along with polarity, contributes to the strong adhesion of quartz particles to the binder.

An important feature of quartz in comparison with other fillers is that it improves the gas permeability of products. As a result, the gases that are heated during heat treatment (water vapor, ammonia, phenol) do not accumulate in the body of the circle, causing the formation of pores, boils, delamination, and output.

An analysis of the microsections of the abrasive tool with the addition of quartz showed that the porosity is reduced by 10-30%. Decreasing porosity increases tool strength.

The increase in quartz in the abrasive mass increases the described effects. However, increasing it to more than 7 wt.%, The process of brining the wheel begins, friction increases, which leads to overheating of the binder, its destruction, the grinding coefficient starts to decrease, despite the fact that the strength of the circle increases.

The introduction of quartz less than 1 May.% Does not allow to fix a positive effect, both the grinding coefficient and the strength of the abrasive tool are of the same order as the abrasive tool made without the use of quartz,

Example. Recipes abrasive mass are shown in table 1.

The calculated amount of grain doped with normal electrocorundum, grade 93A, grain 80 is loaded into a paddle stirrer, moistened with liquid BJ-3 Bakelite. and stirred for 2 minutes.

pulped bakelite of the SPP-012A brand, cryolite, antimonite, quartz are fed to a separate paddle stirrer and mixed for 4 minutes.

The abrasive mass is rubbed through a sieve with a cell size of 2.5 x 2.5 mm to remove aggregate formations. The abrasive mass is ready to make an abrasive tool out of it.

Quartz, which is introduced into the abrasive mass (examples 1-5), is a negative product after crushing of lumpy quartz and subsequent sieving on a sieve with a cell size of 100 x 100 microns. A positive product (with a particle size greater than an LLP of microns) is used in Example 6. In Example 7, micropowder-MlO of quartz obtained by sedimentation is used.

In parallel, a known abrasive mass is produced.

Made from abrasive mass according to examples 1-8 circles have the strength and performance indicators are given in table.2.

The data in Table 2 show that cutting wheels made from the proposed abrasive masses have

Liquid Bakelite BZH-3

Pulverbakelit SFP-012A

Cryolite ANTIMONITE

Quartz size, microns:

Over 100 10-100 less than 10

6 6,5

6.5 6.5 6.5

5 5

2 3.5 2.25. 4.5 3.5 3.5 5.5 2 3.5 2.25 4.5 3.5 3.5 5.5

0.5

s

YU .

tS 248780 .4

higher strength and performance indicators.

The breaking speed of cutting wheels in examples 1-3 is 5-3% higher than in example 8 ,.

The grinding coefficient of cutting wheels in examples 1-3 is 2-0% higher than in example 8.

Cutting wheels made of abrasive mass with a quartz content below the lower limit (example 4). have strength and performance indicators at the level of known ..

An increase in the abrasive mass in the abrasive mass over the upper limit (Example 5) gives the cutting wheels a higher strength (by 25%), but reduces the grinding coefficient.

The introduction of .in the abrasive mass of quartz with a particle size of more than 100 microns and less than 10 microns (examples 6 and 7) does not allow an increase in strength and performance indicators in circles.

Thus, the introduction of abrasive mass as a filler of quartz with a particle size of from 10 to 100 microns makes it possible to increase the discharge strength of the circles and use them to cut the metal heated to Bbmie.

: Table 1

20

25

3.0

7 00 ° С

6.5 6.5 6.5

0.5

 Breaking speed, m / s 135 115 130 110 137 110 110 110

Coefficient

grinding 5.1 5.2 6.0 5.0 4.8 4.8 5.0 5.0.

table 2

Claims (1)

ABRASIVE MASS, containing abrasive material, synthetic resin and fillers, characterized in that, in order to increase the mechanical strength of the tool, quartz with an additional particle size of 10 to 100 μm is introduced into it with the following ratio of components, wt.%: Abrasive material 67-84 Synthetic resin 11-16 Quartz with a particle size of 10 to 100 microns Fillers 1-7 The rest is about N3