SU933427A1 - Abrasive mass composition - Google Patents

Description

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The invention relates to the manufacture of an abrasive tool.

A known abrasive mass for the manufacture of an abrasive tool, including an organic bond based on a phenol-formaldehyde resin, mineral fillers and an abrasive 1.

A disadvantage of the known solution is the relatively low tool life caused by its salting due to the exothermic reaction between fillers (pyrite and cryolite) with low-temperature melting that occurs at a temperature of grinding, which leads to a decrease in the effective ability of the tool. In addition, in the grinding process, volatile fluoride and sulfur compounds are released due to decomposition of cryolite and pyrite, which leads to pollution of the atmosphere and polishing waste.

Nin The latter makes it difficult to recycle the chips.

The aim of the invention is to increase the cutting ability and grinding ratio of wheels for high-speed grinding, while increasing their strength and reducing the release of toxic gases into the atmosphere by adjusting the solid-phase interaction of the filler components in the abrasive sand.

The goal is achieved by the fact that an abrasive molding mixture for making these circles, including an organic bond based on a phenol-formaldehyde resin, a mineral filler (cryolite) in fine condition and an abrasive material, contains carbon coke as a filler and thermally treated limestone as follows Component ratio, wt.%: Organic binder based on phenol formaldehyde resin 9-10 Cryo it4.5-6.5 Stone-coated coke 3.5-6.5 Thermally processed lime5-5-6.5 Grinding mother l 72.5-75.5 Organic binder contains, wt%: phenol-formaldehyde resin (pulverbakelite) 91.6, furfural 4.2 i anthracene oil 4.2, Heat-treated limestone is a product of high temperatures (900-1300. C) to natural ores, at which thermal dissociation of CaCOd occurs. In a heat-treated lime, the lime content (CaO) is in the range of 30-70% J limestone (CaCO) 30-70 weight In the manufacture of grinding wheels from the proposed mixture, the heat-treated limestone enters in the temperature range of 100-500 seconds reaction. with cryolite. The interaction of cryolite with lime of heat-treated limestone leads to the formation of the following products: cryolite of the composition l a-jAIF and fine CaF ,. , NaF. The resulting fine products of this reaction catalyze the reaction of cryolite with limestone, CaCET, leading to the further formation of CaF2 and NaF until complete decomposition of limestone and cryolite. Coal coke in the abrasive mixture, creating a reducing environment, inhibits the decomposition of cryolite and promotes its active solid phase interaction with the heat-treated limestone. The reactivity of the filler components in the proposed mixture at the polymerization temperature contributes to the adhesion of the filler to the bond, and the formation of fine products of solid-phase reactions — dispersion hardening of circles made of this mixture, leads to an increase in their grinding coefficient. The solid phase reaction of cryolite with thermally treated lime associates volatile fluorides and suppresses the melting of cryolite. The reactivity of the filler components in the proposed mixture at the grinding temperature during operation weakens the bond in the thin layer, contributing to the self-sharpening of the wheel and, consequently, increasing its cutting ability. The use of the components of the mixture in a quantitative ratio, less than that indicated, is not enough to fully carry out solid-phase reactions, and the use of the components in the mixture in a quantitative ratio that indicated above results in an increase in the flow of the wheels during operation. An example of a specific embodiment of the invention. Grinding material, a mixture of zirconium and normal electro-corundum, is moistened with furfural, stirred for 10 minutes, then the complex filler is filled in a finely dispersed state (100 µm fraction) and a granted mesh material. -O 19A, mix the components for 10 minutes, moisten the mixture with anthracene oil and mix for another 10 minutes. From the mixture obtained, at a temperature of 165 + 5 ° C. A test pressure of 350 + 10 kg / cm is pressed by experienced grinding wheels with holding for 60 minutes under pressure and samples of a figure eight abrasive tool with holding by pressure for 10 minutes, which are then subjected to heat treatment in a chamber bakelizer at a temperature of 185 C for 20.5 hours. Eight samples were tested in the laboratory for a Mexai strength. Similar comparisons and eights made from a mixture of known composition were also tested in comparison. All test mixes, test circles, eights were made and tested under the same conditions. The table shows the compositions of abrasive molding compounds used to make experienced grinding wheels and eights (eights), and comparative data from their tests.

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From the data in the table, it can be seen that the mechanical strength of the samples made from mixtures 1–12 is higher than the mechanical strength of the sample from the mixture, 13 (according to the known solution) by 13.3%. The use of the proposed abrasive mold mixture in the manufacture of grinding wheels, mainly by hot pressing, poses, as compared with the use of the known abrasive molding sand, to increase the cutting ability of the wheels by 2.3 times, and the rate of fluff rate by 44.4%. In addition, the operation of grinding wheels made of the proposed abrasive sand mixture proceeds without contamination of the atmosphere due to a significant reduction in toxic fluoride gas emissions. Grinding waste is suitable for subsequent remelting.

Claims (1)

1. Patent of Great Britain No. 993894, cl. With 1 G, pub. 1965.