SU689777A1 - Composition for making moulds and cores with heated tooling - Google Patents

Description

(54) MIXTURE FOR THE MANUFACTURE OF CASTING RODS AND FORMS ON A HEATED TOOLING

This invention relates to a foundry, in particular, to the composition of mixtures for the manufacture of foundry cores and molds that are curable in a heated tooling.

Closest to the described invention in its technical essence and the achieved result is a mixture for the manufacture of rods and molds on heated equipment, containing refractory filler, carbamide-furan binder and complex curing catalyst based on sulfite-alcohol stillage, phosphoric acid and water 1.

This mixture is not characterized by high survivability.

The aim of the invention is to increase the survivability of the mixture and reduce its cost.

To achieve this goal, the mixture for making casting cores and molds on heated equipment, including a refractory filler, carbamide-furan resin, sulfite-alcohol bard, an acidic compound and water, contains the following ingredients as an acidic sulfate ammonium compound, weight,%, Urea-furan resin2.0 -3.5

Sulfite-alcohol bard 0,15-0,40

Aafloni sulfate 0.015-0.080 Water 0.30 -0.65

Flame retardant Else. When the ammonium sulfate content is below the lower limit, the rate of hot curing and the strength of the mixture decrease, and when it is above the upper limit, life is deteriorated. vuchest mixture.

Ammonium sulphate is introduced into the mixture in the form of a previously prepared composition with sulphite-alcohol barda and water. Said composition is a complex catalyst for hot curing of the following composition (% of the total weight of the complex catalyst): ammonium sulfate 3-7; sulphite-alcohol bard 32-38; water - the rest is up to 100, the total consumption of the complex catalyst in the composition of the mixture is 0. lts 0,465-1,130 wt.%.

The PH of a complex catalyst, equal to 4.40-4.45, provides mixtures with increased survivability.

When the mixture is heated to a temperature of more than ammonium sulfate decomposes into ammonia and sulfuric acid, which leads to a decrease in the pH of the system and a sharp increase in the rate of curing of the mixture.

The content in the mixture of ammonium sulfate at the upper limit is preferable for those cases when carbamide-furan binders are used with a high content of furyl alcohol (such as resin KF-90

The accepted relationship between sulphite-alcohol barda and water in the composition of the complex catalyst provides good wettability of quartz sand with catalyst and binder and obtaining the minimum strength in the wet state required for sandblasting the production of rods using a hot snap.

Quartz sand 2K0315 Quartz sand 2K016 Urea-furan resin Sulfite-alcohol bard Ammonium sulfate Water

Complex hardener (total)

The complex hardener based on sulphite-alcohol bards, water and 10% orthophosphoric acid / The rods of the proposed mixtures (eights) were cured in a heating cabinet at a temperature of 220–240 s for 5–10 min, or in an OSTO heated heating rod. 1M 60

When the content of ammonium sulfate in the composition of the complex catalyst is more than 7 wt.%, The stability of the state of the catalyst during storage is disturbed (stratification and precipitation are possible).

The order of introduction of the ingredients during the preparation of the mixture is as follows. A pre-prepared composition (complex catalyst) based on sulphite-dry stillage, ammonium sulphate and water is introduced into the sand, mixed until uniformly distributed, after which urea-furan binder is added and mixed again.

Rods are made from the proposed mixture, the quality of which does not deteriorate with fluctuations of the heating temperature of the equipment and the dwell time of the heated equipment.

The invention is illustrated by the following example.

In tab. 1 shows the composition of the mixtures.

T a b

faces

47,68548.25 48.77

47,68548.25 48.77

3.52.75 2

0,40,275 0,15

0.08 0.045 0.015

0.65 0.43 0.3

4.13 0.75 0.465 at the same temperature for 40-60 seconds. The test results are shown in table 2.

Vitality, hour Humidity,%

Compressive strength in wet condition, kgf / cm

Tensile strength in the cured state, kgm / cm

Claims (1)

Gas permeability, units From the data of Table 2, it follows that the mixture in comparison with the known mixture has a higher (2–4 times vitality while maintaining at approximately the same level the other physicomechanical and technological properties. 1 ton of ammonium sulfate is cheaper than 1 ton of phosphoric acid, and the consumption of primary in the proposed mixture is lower than the cost of the second in the known mixture. Therefore, the cost of the proposed mixture is lower than the cost of the known. Formula of the invention The mixture for the manufacture of casting cores and molds on heated equipment, including refractories th on T a b l a 2 and n 9 1.2 13.5 4 1.6 1.6 0,014 0,014 0,014 0,016 filler, carbamide-furan resin, sulfite-alcohol bard, acidic compound and water, characterized in that, in order to increase its survivability and cost reduction, it contains ammonium sulfate as an acidic compound in the following ratio of ingredients, weight .% Carbamide-furan resin2.0 -3.5 Sulfite-alcohol bard0.15 -0.4 Ammonium sulfate 0.015-0.08 Water0.3 -0.65 Refractory fillerEverything else. Sources of information taken into account in the examination 1. USSR author's certificate 387777, cl / H 22 C 1 / 00.02.10.70,