SU1748913A1 - Sand for casting molds and cores - Google Patents

Abstract

The invention relates to foundry, in particular, to the manufacture of cores and molds on a heated snap. The essence of the invention: the mixture has good technological properties and is hygienically acceptable. In order to prevent cracking of the rods during storage, diesel fuel was introduced into its composition in combination with silicone emulsion KE-60-09 and glycerin in the following ratio of components, wt.%: Aluminum-chroma-phosphate binder (AHFS) 2.5-5.5, water - 0.5-3, diesel fuel 0.3-1.0, silicone emulsion KE-60-09 0.1-0.2, glycerin 0.1-0.3, powdered quartz 2-3, quartz sand - rest. The mixture is prepared by mixing the starting components in any mixing equipment used in foundries. Sand is loaded into the runners, then the AHFS is poured in and then, after mixing for 1-2 minutes, diesel fuel and KE 60-09 silicone emulsion are poured in, the dust-like quartz is stirred for 1 minute and stirred for another 2 minutes. 2 tab. cl

Description

The invention relates to foundry and can be used for the manufacture of casting molds and rods of phosphate mixtures on a heated snap.

A known mixture for the manufacture of casting cores, containing, in wt.%: Aluminum-chromophosphate binder, 2.0-2.3; glycerol-0.5-1.0 and refractory filler - the rest.

The disadvantages of this mixture are the cracking of the rods during their storage, as well as the high cost.

The core mixture is also known, containing, in wt.%: Aluminum-chromophosphate binder - 2.8-3.6, glycerin - 0.2-0.3, aqueous polyox composition - 1.7-2.5; powdered quartz - 1.6-2.4 and quartz sand else (auth. St. USSR number 1322569, class B 22 C 1/16, 1984, unpublished. In the open press).

The disadvantage of this mixture is that the rods made from it are cracked during storage, and the cost of the mixture is increased due to the use of expensive polyox.

A mixture containing in wt.% Is also known: aluminum-chromophosphate binder - 2.2-4.5, water - 0.5-3.0, higher fatty alcohols - 0.05-0.2; powdered quartz - 1.6 - 2.4 and quartz sand - the rest.

SUMMARY OF THE INVENTION The essence of the invention is that the mixture containing a refractory filler based on silicon dioxide, an aluminum-chromophosphate binder, water, powdered quartz, and a technological additive contains the diesel

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fuel with a viscosity of 3.5–8 eats, an aqueous solution of a silicone emulsion with a pH of 6.0–7.5, and a content of 17.5–20.0 wt.% silicon and glycerin.

The alumochromophosphate binder (AHPS) was used with a density of 1.6-1.75 g / cm3. AHFS has the following chemical composition, in wt.%: AlaOs - 6.5-9.0; SpgOz - 3.5-4.5; P20s - 35.0-39.0; 50l - not more than 0.5; formaldehyde - not more than 0.2; loss on ignition - 47-55.0. Silicone emulsion used brand KE-60-09 with the content of 17.5-20.0% silicon; The pH of the aqueous solution is 6.0-7.5, which is an aqueous composition of polyvinyl alcohol and dimethylsiloxane rubber.

Diesel fuel is a liquid petroleum fuel for automotive engines. The use of two grades: winter DZ (viscosity at 20 ° С - 3.5-6.0 ets., Cetane number - 40, sulfur content 0.2%, taacr - 45 ° C; tBCn. - 50 ° C) and summer DL (viscosity - 3.5–8.0 est., cetane number 45, sulfur content –0.2%, taacr. –10 ° C, teen. –60 ° C). Glycerin was used as a technical one, which is a triatomic alcohol.

Quartz sand was used according to GOST 2138-84.

Powdered quartz used the obtained mildms of pure quartz sand in ball or vibration mills.

The introduction of a mixture of silicone emulsion, diesel fuel and glycerin contributes to the plasticization of the film AHFS, relaxation of internal and thermal stresses, which leads to the elimination of the cracking of the rods.

The mixture is prepared by mixing the starting components in any mixing equipment used in foundries. The runners are loaded with sand, then water and glycerin are poured in, mixed for 1 minute and AHFS is injected, further mixed for 1-2 minutes, diesel fuel and CE-60-09 organic organic emulsion are poured, and all the ingredients are mixed for 1 minute, after which the quartz powder is filled up and the final mixing is carried out for 2 minutes.

The compositions of the mixtures according to the invention are given in table 1, their physico-mechanical and technological properties are given in table 2. From the data given in Table 2, the mixture according to the invention as compared with the known one has a shorter curing time, the cracking of the rods is eliminated during storage.

Claims (1)

Claims of the Invention Mixture for the manufacture of casting molds and cores on heated equipment, containing a silica-based refractory storage unit, an aluminum-chromium-phosphate binder, water, powdered quartz, and a technological additive, which in order to reduce the thermal stresses of the mixture, the duration its curing in the heated equipment and elimination of cracking of the rods and forms during storage, it contains diesel fuel with a viscosity of 3.5-8 eats as a technological additive, an aqueous solution of silicon silicon . Eskoy emulsion pH 6.0-7.5 and comprising 17,5- 20.0% by weight silicon and glycerol in the following ratio of ingredients, wt%: Alyumohromfosfatnoe communication zuyuschee2,5-5,5 Water 0.5-3.0 Diesel fuel viscosity 3,5-8,0 est0,3-1,0 An aqueous solution of silicone emulsion pH 6.0-7.5 and with a content of 17.5-20.0 wt.% silicon 0.1-0.2 Glycerin 0.1-0.3 Dusty quartz2.0-3.0 Refractory filler based on silicon dioxide Else Table 1 table 2