SU1091979A1 - Method for preparing mould wash - Google Patents

Abstract

THE METHOD FOR PREPARING CASTING PAINTS, used mainly to obtain the metal-ceramic layer on castings, includes pouring water into the mixer, introducing refined alkylaryl sulfonate, loading boric acid, quartz sand and introducing neutralized black contact with the help of drawing, throwing neutralized black contact with the help of quartz sand, and drawing neutralized black contact with the help of quartz sand. covering ability and strength of the coating formed by the paint, boric acid in an amount equal to its limiting solubility in water at temperatures preparing paints, charged before introduction refined alkilarili sulfonate, and the rest amount of boric acid charged after the Introduction (I refined spinning alkilarilsulfon ta.

Description

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110 The invention relates to foundry, in particular, to the methods of making foundry paints used mainly to obtain the cermet layer on castings. There is a known method for preparing a casting paint by mixing loose components in a paint mixer with water ti. The disadvantage of this method is that it does not take into account the possibility of the interaction of some bulk components with water, which does not allow using this interaction to improve the technological properties of the paint. The closest to the proposed technical essence and the achieved effect is a method of preparing a casting paint used to obtain a cermet layer on a casting, including pouring water into the mixer, introducing refined alkyl aryl sulfonate, loading boric acid, silica sand and introducing neutralized black contact at Continuous mixing is composed of 1X components. In this method, the paint components perform the following functions: water - dispersion medium, refined alkyl alkyl aryl sulfonate (DS-PAC) foaming agent, boric acid granular soluble modifier, quartz sand - granular filler, neutralized black contact (LFC 1 - antifoam 2 1. This method although provides for a certain sequence of introduction of all the components of the paint, but The sequence of the components is not optimal. Boric acid, partially dissolved in water, is the binder. However, when you enter it after DS-RLS, it has a solubility lower than in pure water. This is because the foaming agent, adsorbing on the modifier grains, forms a film that envelops the grains and retards or completely blocks the solubility of the modifier. As a consequence, the solubility of the modifier in water, which is equal to 5.04% for boric acid, in an aqueous solution of the frother DS-PAC, barely reaches 2.7%. This prepared paint has unsatisfactory technological properties, in particular, poor covering power, due to which the process of applying paint is significantly lengthened, and also the very low strength of the coat obtained on the basis of such a pattern. It cracks, partly falls off during transportation of the mold assembly, clogs the metal of the casting. The purpose of the invention is to improve the ability of the fabric and to increase the strength of the coating formed by the paint. The goal is achieved by the method of preparing the casting paint used mainly for obtaining the cermet layer on the castings, including pouring water into the mixer, introducing the refined alkylaryl sulfonate, loading the bory acid; and the introduction of neutralized black kongakt with their continuous mixing, boric acid in an amount equal to its limit solubility in water at the preparation temperature of the paint is loaded before the introduction of refined alkylaryl sulfonate, and the rest of boric acid is loaded after the introduction of refined alkylaryl sulfonate. Loading the modifier in an amount less than the limit of solubility is impractical because the properties of the paint deteriorate due to the low concentration of the binder. When the modifier is loaded in an amount greater than the solubility limit (for example, the total amount of boric acid), the foaming capacity of the frother decreases sharply, since part of it is used to create an adsorption film on the modifier grains and does not hinder the formation of foam. This necessitates an increase in the content of the foaming agent in the paint, which is undesirable from the point of view of its influence on the impregnation of the coating of a liquid metal coating,. The non-combustible residue resulting from the combustion of the blowing agent worsens the wetting

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OMor.Tij is ferrous oxide liquid metal, fills the pores of the ceramic coating, preventing metal from penetrating into them.

Under identical conditions, a comparative analysis of the method for preparing the casting paint according to the invention and the prototype is carried out. Test paint containing, wt.%: Quartz sand 55.7; boric acid 15.3; DS-PAC 0.3; FCM 0.08; water 38.62,

The paint is prepared in a tank with a turbine agitator at different water temperatures (teaper-atura paint preparation). In the proposed paint preparation method, the amount of boric acid introduced before the introduction of the blowing agent is 50, 100 and 150% of the limit of its solubility in water at the paint preparation temperature. The solubility of boric acid in water at 20c is equal to 5.04%, and at 40 ° C - 8.72%.

Paints prepared in various ways are evaluated for coating ability and strength. Paint coverage is evaluated when applied 94

Research Institute of its spray on the cores with surface temperature. The coating obtained as a result of the rods (in all experiments, a thickness of 3.0-3.2 mm was tested for crumbling according to GOST 2189-62 and the scattered mass of paint was estimated as a percentage of the paint used during application. Coatings are also tested for abrasion resistance according to GOST 10772 -78, for which they are sprayed onto a frosted glass heated to

Next, the coated rods are installed in a casting mold and cast it with cast iron of eutectic composition at 1250 ° C. From the obtained castings, samples are prepared for measuring the thickness of the cermet layer to determine the degree of impregnation of the ceramic coating with metal. This indicator is estimated in percent as the ratio of the thickness of the cermet layer to the thickness of the corresponding ceramic coating.

The results of the experiments are shown in the table.

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H As can be seen from the table, with the introduction of boric acid after DS-PAC (experiments 1 and 21 and before DS-PAC, but in an amount less than its limiting solubility at the paint preparation temperature (experiments 3 and 4 /, the paint is characterized by unsatisfactory covering power As a result, the coating on the rods has under-the-teks and at the same time unpainted areas of the rods are observed. To obtain a ceramic coating on the rods with a thickness of 3 mm, it is required for paint in experiments I and 2 times five times, and for paint in experiments 3 and 4 - three times. .Lawability cr The prototype cooked plates (samples 1 and 2 / are high and are in the range of 70.5-74.6%. For the coating of these coatings, no more than 1740 g of sand are needed. The introduction of boric acid before DS-RAS, even in amount less than the solubility limit (experiments 2 and 3 /, slightly increases the strength of the coating: shedding decreases by 14.5-16.6%, and the resistance to abrasion increases by 17-18%. With the introduction of boric acid before DS-PAC in an amount equal to (experiments of 5 and 6 greater) (experiments 7 and S) of the limit of its solubility, the coating power of the paint will improve dramatically and, consequently, rytie obtained evenly without streaks; applied with a layer of 3.0-3.2 mm for 1-2 times. The strength of these coatings is higher than in Experiments 1 and 2. Their dropping ability decreases on average by 1.67 times, and the resistance to abrasion increases by 30-54%. At the same time, the strength of the coatings in experiments 7 and 8 is somewhat lower than in experiments 5 and 6. This is due to the negative effect of a large amount of DS-PAC introduced into the paint additionally over the calculated I to increase its sedimentation stability, because of an excess of boron acid in water, DS-RAS in a calculated amount does not give enough foam. The addition of DS-PAC in excess of the calculated amount adversely affects the penetrability of ceramic coatings with liquid metal. Ti experiments 1-6 degree of impregnation is 52-55%, and in experiments 7 and 8 only 30-32%, i.e. 1.71, 8 times less. The negative effect is even more pronounced, up to the lack of impregnation, if all the boric acid is injected before the XRDPS with a corresponding increase in the content of the latter by 30-37%. Based on the above results, the optimal amount of boric acid loaded into the mixer before the DS-PAC should be considered as an amount equal to the limit of its solubility at the preparation temperature. The implementation of the invention allows for a 15-20% increase in labor productivity in the paint sections of the rods of the tool shops, a 30% reduction in the amount of paint used to obtain the cermet layer on the castings, and an increase in the quality of products.

Claims (1)

METHOD FOR PREPARING A CASTING PAINT, used mainly for producing a ceramic-metal layer on castings, including pouring water into a paint mixer, introducing refined alkylarylsulfonate, loading boric acid, quartz sand and introducing neutralized black contact with continuous mixing, characterized in that, for the purpose improve hiding power and increase the strength formed by the paint coating, boric acid in an amount equal to its ultimate solubility in water at a temperature at paint preparation is loaded before the introduction of refined alkylarylsulfonate, and the remaining amount of boric acid is loaded after the introduction of refined alkylarylsulfonate. SU „., 109197.9