SU1210950A1 - Binder for making moulds and cores - Google Patents

Description

 , one

This invention relates to a foundry, in particular, to compositions of bonding materials used to make foundry molds and cores.

The aim of the invention is to increase the strength after heat drying and reduce the rejection of rods and molds by increasing the film-forming part and reducing the amount of solvent in its composition, the USK binder being used as the latter, and the tar used as the film-forming agent.

The tar is a bottoms (CO) distillation of fatty acids and is a by-product of the production of soap and fats. QoS are formed by the distillation of fatty acids from vegetable oils. animal fats and their mixtures.

Tars are composed of high molecular weight limit and unsaturated kirov compounds. They contain stearins and their esters, gossypol (pigment) and other hydrocarbon and nitrogen-containing compounds.

Soapstock stock of black cottonseed oil and technical grease should meet the following requirements:

-

-

Homogeneous product from liquid to a greasy consistency, from brown to black.

0.90-0.95 65-70

30-70 .43-52

Absent

250-285 305-522

Mol the weight is determined by the cryoscopic method using benzene.

502

The USK binder is a solution of the polycondensation products of synthetic fatty acids activated by asphalt-resin additive in a solvent isolated from narrow gasoline fractions.

The use of the USK binder as a solvent ensures the production of a new complex binder, per unit volume of which increases the amount of film-forming CO and decreases the amount of solvent. This ensures that the bonding ability of a new complex binder increases, which significantly increases the strength of the mixture in stretching in a dry state. The use of the proposed binder increases the overall and surface strength of the rods and shapes, which ensures high dimensional accuracy and cleanliness of the surface of castings and reduces the scrap of rods, shapes and castings that occur during

transport operations, drying and pouring.

Increasing the strength of the mixture in the proposed binder makes it possible to reduce the consumption of the binder and, consequently, reduce the cost of castings, as well as improve sanitary and hygienic conditions in foundries.

Binder was prepared by mixing the ingredients in the specified ratios x listed in Table. one .

Table

Tar 25 35 40 50 45 Binder USK 75 65 60 50

An increase in tar content in bonding more than 50.0 wt.% Is undesirable, since this increases its gas-creativity, and a decrease in its amount below 25 wt.% Leads to a decrease in strength. The amount of solvent USK in the binder should be no more than 75 wt.%, Since an increase in its content leads to a drop in strength, and a decrease in its content below 50 wt.% Will increase the degree of friability.

For a comparative assessment of physical, mechanical and technological

Binding known (tar 70-75% and white spirit 25-30%)

The proposed binder

LKBZH

Mixtures were prepared in laboratory runners. Mixing weight 3 kg. First, the dry components were loaded and mixed for 2 minutes. Then the binder was poured, the time was stirred. Compressive strength in the wet state, kgf / cm

Tensile strength in dry condition, kgf / cm

Gas permeability Accuracy,% Gas production, Humidity,% Binder specific weight, g / cm

Binder viscosity as per OT-4 s. at 20 C, s

Drying time of the rod at 250-260 ° C, h

go I

mixtures

in table 2

famous prep

specified

Table 2

2.5

2.0

2.0

3.5 3.5

3.0

Vani 3 min. Then sulphite-alcohol bard was poured and mixed for 3 minutes.

The properties of the prepared mixtures are given in table. 3

Table 3

0.06 0.07

0.075 0.08 0,, 1-0.15

5 12109506

From tab. 2 and 3 it can be seen that the pre-optimal for their use

Increased strength increases in foundries. dry stretch mixtures

The research institute is almost double in comparison with iz-, use of a binder in the middle, other physicomechanical js can increase surface strength

the properties are retained on the molds and rods, as well as their common

the required level. strength, which contributes to the reduction of the physical and mechanical properties of the blend of their marriage during transportation and

These binders I, It, III are metal casting.

Claims (1)

A BINDER FOR THE PRODUCTION OF CASTING FORMS AND RODS, including tar and an organic solvent, characterized in that, in order to increase the strength after thermal drying and reduce the rejection of rods and molds, the binder contains the polycondensation product of synthetic fatty acids as an organic solvent, activated asphalt resin compounds (USK), in the following ratio of ingredients, wt. ^: . Tar 25-40 Polycondensation Product of Synthetic Fatty Acids Activated with Asphalt Resin Compounds (USK) 60-75