SU884821A1 - Suspension for producing refractory casting moulds with use of investment patterns - Google Patents

Description

(54) SUSPHASIA FOR THE EXAMINATION OF REFRACTORY

CASTING FORMS BY THE MELTED MODELS The invention relates to foundry production, namely, the compositions of refractory suspensions used ol the preparation of molds on melted mopel in which the casting of chemical K1c active metals, for example titanium, are obtained. A known refractory suspension for the preparation of ceramic molds in melted models fll. . A suspension consists of a filler in the face of a mixture of electrocorundum powder and powder fraction and a binder in the form of ethyl silicate in the following ratio, wt.%: Electrocorundum of the micropowder fraction64 Electrocorundum of the powder fraction 16 Ethyl silicate 2O. It forms oligons with reactive metals, such as titanium, because of the need for long-term treatment of pyrolytic carbon in the process of their calcination (for 36 hours) to form on them surfaces of a protective coating that protects the forms from interaction with the chemically active metal poured into them. In addition, forsil from this suspension has low strength before calcination, which leads to cases of destruction during technological operations of calcination. A known refractory suspension 1.2J for the manufacture of ceramic molds in melted models for casting reactive metals, which contains a solid refractory binder, such as microcorundum micropowder fraction, a binder — a hydrolyzed ethyl silicate solution and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed ethyl silicate solution and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate, and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate, and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate and a hardening additive — polyethylene-enoxide, a representative, a hydrolyzed solution of ethyl silicate and a hardening additive — polyethylene-enoxide; polyethylene with a molecular weight of 10OOOO - 5OOOOO, at the following ratio of components, wt.%: Refractory filler 7O-8O Polyethylene O, O1-1.5 Hydrolyzed solution etklsili ataOstalnoe In preparing the slurry polietilenokeil dissolved in hydrolyzed ethyl silicate solution. Then the filler is poured into the resulting solution and the components are mixed until the mass is obtained. The disadvantage of the known suspension is the duration of up to 48 hours of the use of powdered polyethylene oxide in the liquid phase of the suspension (hydrolized. Solution of ethyl silicate). In addition, the forms of this suspension have insufficient strength after calcination, which leads to the destruction of the forms, naprmer, with the centrifugal method of pouring metal. The purpose of the invention is to reduce the time of preparation of the suspension and increase the strength of the forms after calcination. The goal is achieved by the fact that a refractory suspension is known, containing a refractory filler and a hydrolyzed solution of ethyl silicate, as a technological 1T1 additive contains proxanol in the following ratio of ingredients, wt.%: 1.4 Refractory filler 70-85 Proxol 0.1-2.0 Elastic Proxyol Hydropized Ethyl Silicate Solution is a copolymer of ethylene oxide and propylene oxide with a molecular weight of 640 O-1000 O. Proxonol is a transparent liquid that is easily soluble in water and many organic solvents (ethyl alcohol, acetone, etc.), as a result of which the npv.rot suspension process is significantly reduced. In addition, molds made from this slurry are highly durable after calcination due to the fact that during the process of calcining molds in a reducing gas medium, it decomposes with release of pyrolytic carbon, which additionally binds the refractory filler particles to each other. Suspension formulations were tested with an optimal content of a refractory filler and hydrolyzed ethyl silicate, differing in the content of loxonol or its absence (Table 1. Table 1

Fireproof nopopnitpe

(ectrocorundum micropowder

fractions)

Proxonop

Popietipenoksizitsa solution of etipsipikata

(with social symposium SiO 12%)

With this content of silicon dioxide, the chemical inertness of the forms is maximized.

As a refractory filler, other highly refractory powder materials that are chemically resistant to active metals, such as zirconium oxide, bakor, can also be used.

Each suspension is prepared as follows.

in a way.

. To the mixer pour a hydrolyzed solution of ethyl cmlic and proksonol and pour the electrocorundum mm powder, then mix everything at a frequency of rotation

75

75 2.0

1.0

23.024.0

activator 2800 rpm to obtain

homogeneous mass.

The preparation time of the suspension is 0.8 hours. The suspensions are made into forms of titanium by melting models. To do this, prepare the suspension

model blocks are dipped, then they are sprinkled with ectrocorundum of the grain fraction and dried for 1.1 hours. Thus, 7 layers are applied.

Claims (2)

Then, a model composition is smelted from the shells and the forms are calcined in a precautionary gas mixture (a mixture of hydrocarbon and nitrogen) for 12 hours at. 5 In finished forms wash down the alloy W 5L. The slurry preparation time for compounds 1 and 3 is 0.8 hours each, and 4 - 48.8 hours. Forms are made of suspension (1-4) for 6O hours. The thickness of the oxidized layer on the surface of the taps, made in forms of suspensions em, mm: 1234 O, 3 O, 2 0.15 0.38 From the Viano table, that the duration of the preparation of the proposed suspension is 48 hours less than the known suspension. The strength of bending forms after calcination is also higher than that made from a known suspension 1.31, 8 times. This is achieved due to the pyrolytic carbon released during decomposition of Proxol. When proxol is contained in a suspension less than 0.1 wt.%, The strength of the forms becomes less acceptable, and when its content is more than 2.0 wt.%, There is a further increase in strength. molds are also higher than acceptable, since the increased form strength prevents the metal from shrinking during solidification and the destruction of the casting is possible. The thickness of the oxidized layer on the surface of the castings obtained in the forms of the proposed suspension is 2–30% less than that of the dips obtained in the forms of the known suspension. This is achieved due to the fact that the pyroptic perperum released during the passage forms a protective film on the perimeter of the forms, a titanium film. Tables 1 and 2 show the compositions and 8848214 properties of suspensions. Table 2 stores the form from interaction with molten titanium. The duration of the manufacture of the forms is the same as that of the known suspension. The strength of the bending forms before calcination is at the level of the strength of the forms from a known suspension. The implementation of the proposed invention will reduce the time of preparation of the suspension, increase the strength of the forms after calcination. DETAILED DESCRIPTION OF THE INVENTION A suspension for the manufacture of refractory casting molds in melted models for casting reactive metals, containing a refractory filler, a hydrolyzed solution of ethylsilicate and a hardening additive, so that it is used to reduce the time preparing the suspension and increasing the strength of the forms after calcination, it contains proxanol as a technological strengthening additive in the following ratio of components, wt.%: Refractory filler 7O-85 Proxonol 0.1-2 O Hydrolyzed p etilsilikataOstalnoe target Sources of information received into account when 1.Avtorskoe examination certificate USSR № 394152, cl. In 22 C 1 / OO, 1967. 2.Association of SSSS-. No. 457528, cl. In 22 C 1/00, 1973.