SU768528A1 - Mixture for producing water soluble cores - Google Patents

Description

Table 1

Calcium nitrate — Ca (Li3) 2 — is a white crystalline powder with a molecular weight of 164.9. Density is 2.36 kg / cm. Melting point 56 ° C. Solubility in water at 20 ° С - 126 g / 100 g Noob, at 100 ° C - 363 g / 100 g H2O.

Potassium orthophosphate is a colorless transparent crystals, in the mass of white, hygroscopic, molecular weight - 338.38. Melting point is 1340 ° C. The solubility in water at 20 ° С is 98.5 g / 100 g НЗО, at 60 ° С - 178.5 g / 100 g Н20. Potassium orthophosphate contributes to the phosphorization of the surface of the cooled cavity, which eliminates the possibility of metal corrosion. In the case that calcium nitrate is used as a refractory material in a mixture, the mixture contains talc or aerosil, or magnesium oxide, or alumina, or graphite, or iron oxide. When used in potassium orthophosphate mixtures, the mixture contains talc or magnesium oxide, or alumina, or iron oxide.

A mixture for making water-soluble rods is produced by mechanically mixing them until a uniform mass is obtained. In the final form, the mixture is a powdery mass.

In order to obtain water-soluble rods, the mixture obtained is filled in a special mold, a die is inserted and pressed at a specific pressure of 1500-2000 kgf / cm.

The extruded rods are heat treated to remove residual moisture and increase the mechanical strength of the rods.

The ratio of components in the mixture is optimal, since going beyond the limits of these components in the direction of their reduction does not allow; significantly increase the solubility of the rods.

Going beyond these components in the direction of increasing increases the hygroscopicity of the charge, which impairs the manufacturability of the process of forming (pressing) the rods.

The optimal ratio of the ingredients of the mixture is illustrated by the compositions and

technological properties that

are presented respectively in table. 1 and 2.

table 2

As follows from the table. 1 and 2, the use of components in the mixture in other quantities that are EXCELLENT from the examples indicated in the formula either weakly increases the solution of iMOcfb rods compared to the prototype, or results in a mixture that is poorly compressible at room temperature and atmospheric pressure due to the high hygroscopicity of the moldable charge.

The invention is illustrated by examples No. 1-5 and by the stakes and technological properties, which are respectively given in table. 3 and 4.

Example 1. 89.5% by weight of powdered sodium chloride, 10 sec.% Of calcium nitrate and 0.5% by weight of aerosil are displaced

until a homogeneous mass. The mixture is formed in special molds with a specific pressure of pressing 1800 kgf / cm. Pressed rods are heat treated at 300 ° C for three hours.

Molded water-soluble rods are used to produce Oil Cooling strips in forged or cast pistons of internal combustion engines.

Washing water-soluble rod with tap water during forging (casting) a D-70 engine piston, with a diameter of two channels of 80 mm each, takes 1 h 55 min versus 3 h 50 min for rods made of the known charge.

Example 2. 84% by weight of powdered sodium chloride, 15% by weight of potassium orthophosphate and 1% by weight of talc are mixed to Table 4

homogeneous mass. The mixture is molded in special molds, with a specific pressure of 1800 kgf / cm. Pressed, the rods are heat treated at 700 ° C for three hours. The obtained water-soluble rods and Table 3

used to produce cavity oil cooling in cast or forged powders. Water washing up of a water-soluble rod during forging (casting) a D-70 engine piston through 2 channels with a diameter of 10 mm, drilled in a mold (casting), occurs within 1 hour and 50 minutes versus 3 hours and 50 minutes for rods made of the known mixture.

Example 3. 78.5% by weight of powdered sodium chloride, 20% by weight of potassium orthophosphate and 1.5% by weight of talc are mixed until a homogeneous mass is obtained. Molding, heat treatment and washing of the rod are performed as in Example-1. Water leaching occurs within 14 to 10 minutes versus 3 hours and 50 minutes for rods made of the known charge: Example 4. 68% by weight of powdered

sodium chloride, 30 wt.% potassium ortho-phosphate and 2 wt.% magnesium oxide are mixed until a homogeneous mass is obtained. Molding, heat treatment and vyshshanie water: the rod occurs within 1 h-against

3 h. 50 min. For rods made of the known charge ...

Example 5. 58% by weight of powdered sodium chloride, 40% by weight of potassium orthophosphate and 2% by weight of talc are mixed until a homogeneous mass is obtained. The molding, heat treatment and washing of the core are carried out as in Example 1. The washing of the rod with water occurs within 50 minutes versus 3 hours and 50 minutes for rods made of the known charge.

Strength characteristics were determined on a semi-automatic 084M strength tester.

The amount of residual moisture of the pressed rods after heating them at 300 ° C for 3 hours is not more than 0.2%.

The mixture in accordance with the invention has a scrubbing capacity 2 times better than is known, by improving the solubility of the rods.

And when using potassium orthophosphate, it has a reduced corrosive effect of the salts of the mixture on the material of the part while maintaining the high thermal stability of the water-soluble rod due to the phosphorization of the surface of the parts.

The mixture according to the invention can be used in the production of cast and forged pistons of internal combustion engines of light metals and their alloys.

Claims (3)

1. Mixture for making water soluble rods, including chloride sodium and refractory material, distinguish w; and so that, in order to increase the solubility of the rods, it additionally contains calcium nitrate or potassium orthophosphate in the following ratio of ingredients, wt.%: Refractory material 0.5-5.0 Calcium Nitrate or potassium orthophosphate 10-40 Sodium chloride 2. A mixture according to claim 1, characterized in that, in order to reduce the corrosive effect of the mixture on the material of the parts while maintaining the high temperature resistance of the rod, it contains 15-40% by weight of potassium orthophosphate and 1-2% by weight of the refractory material. 3. A mixture according to claim 1, characterized in that as a refractory material, the mixture contains talc, aerosil or magnesium oxide, or alumina, or graphite, or iron oxide. 25  Sources of information taken into account in the examination 1. The patent of Germany No. 1483641, cl. In 22C 9/10, 1973. 2. USSR author's certificate number 435045, cl. B 22 C 1/12, 1972 (prototype).