SU871998A1 - Solution for treating investment patterns - Google Patents

Description

(54) SOLUTION FOR TREATING PERFORMED MODELS

one

The invention relates to foundry production, namely, compositions for processing models produced.

Solutions for the treatment of the melted models are known, which are aqueous solutions of anionic surfactants 1.

However, these solutions do not provide the required quality of the casting surface (the defect of castings on the ball spurts of the metal is high), which leads to an additional metalwork processing of castings and an increase in the labor intensity of the casting manufacturing process.

The closest in technical essence and the achieved result to the proposed is a solution containing ethyl silicate, hydrochloric acid and water for a given ratio of ingredients 2.

This solution does not provide the required quality of the surface of the castings, since during processing the model of .blocks has poor wetting properties. This is due to the fact that a large amount of ethyl silicate in the hydrolyzed solution (22% based on the content of

conditional silica) leads to an increase in the wetting angle. The increase in the wetting angle is due to the spatial difficulties in the manifestation of surface forces with the enlargement of polymer molecules and the increase in their total number. The specified amount of conditional silica in solution also leads to

10 rapid aging of the solution, accompanied by an increase in viscosity, which leads to an increase in casting defects due to spherical flows of metal.

15

The purpose of the invention is to improve the quality of the surface of the castings by reducing the defects in the ball flows of the metal.

20

To achieve this goal

The solution for processing the melted models, including ethyl silicate, hydrochloric acid and water, additionally

25 contains anionic surfactant of carboxylic acids and their salts in the following ratio of ingredients, wt.%:

Ethyl silicate 25-28

30 hydrochloric acid 0.15-0.3

Anionic surfactant of carboxylic acids and their salts 0.04-0.1 Water

The anionic surfactant of carboxylic acids and their salts (wetting agent CB-133) is an octa-based (glycerol-1.3) wicked salt and a mixture of 2- (2-ethylhexin) succinic acids.

When processing the melted models with the proposed solution, the surface of the model is activated, the surface tension decreases, increasing the wetting ability of the model with suspension. As a result, the adhesion of the suspension to the melted model is improved, which leads to a reduction in the defect of castings due to the ball spurts of the metal and a reduction in the labor intensity of the manufacture of the castings.

The compositions and properties of the proposed solution are given in Tables 1 and 2.

Ceramic forms are prepared using a slurry of powdered quartz in an aqueous ethyl silicate binder. Forms are prepared by applying four coats. Before applying the 1st layer of the refractory coating, the model blocks are immersed in the proposed solution, kept in the solution for 2-5 s. After exposure to air for 10–15 s, four layers of refractory coating are applied according to the conventional technology. Ceramic forms are calcined in flasks with a base filler of 8 hours. Fillings are made with 50 L steel. Castings are visually inspected for the presence of ball spikes in sharp corners, which are usually removed by metalworking.

The proposed solution is prepared by stirring ethyl synclate - 40 V

water in the presence of hydrochloric acid and a surfactant (wetting agent CB-133). 18% by weight of the amount of ethyl silicate-40 is poured into the hydrolyzer, hydrochloric acid is poured into it and all ethyl silicate is added with constant stirring. When the temperature reaches 45-5 (PC, the rest of the water is poured into the solution. 3-5 minutes before the end of mixing, the surfactant CB-133 is added. The total time of stirring the solution is 40 minutes. After preparation, the solution is allowed to settle for 5-7 minutes - The optimal addition of ethyl silicate is within 25-28 wt.%, With a further increase in the amount of its scrap on the metal ball spikes in sharp corners remains at the same level. Therefore, an increase in the content of ethyl silicate in the solution above 28 wt.% Is economically uncensible. A decrease in the content of ethyl silicate in the solution leads to poor wettability with the solution of the models, as a result of which the reject rate for the ball flows of metal f in sharp corners increases.

The optimal addition of the surfactant CB-133 is 0.04-0.1 wt.%. Reducing the surfactant content below 0.04 wt.% Does not give a positive effect on reducing the rejection of ball nodules. Increasing the surfactant content in ae to 0.1 weight.% Is not economically feasible.

The use of the proposed solution will improve the applicability of the suspension to the model, which will provide a high-quality surface for steel castings by reducing defects due to ball flows in sharp corners, this will reduce the laboriousness of the metalworking processing of castings.

Table 1

25 0.15

0.04

74.81

28

89.7

25 0.3

0.15 0.2 0.3

0.06 0.08 0.1 71.47 74.72 71.6

ten

The number of castings with ball flows of metal, 14

Flexural strength at room temperature, kgf / cm

Bending strength after firing, kgf / cm

Claims (2)

1. Patent CIA 3156023, cl. , 1973. 2. The author's certificate of the USSR 485815, cl. B 22 C 1/20, 1969.