SU1748916A1 - Binder for manufacturing casting bars and heat hardening molds - Google Patents

Abstract

The invention relates to foundry, in particular for the manufacture of casting cores and heat curing forms. SUMMARY OF THE INVENTION A binder comprising a solution of bottoms of fatty acids and activating additives in the form of asphalt-resin compounds in the residue from the release of narrow gasoline fractions of 8.3-16.66% and the active reagent, it contains urotropin 3,33-5,0 as the last and additionally tall oil 3.33-5.0 and technical lignosulfonates - the rest. The proposed binder provides for the reduction of internal stresses, elimination of the crumbling of the rods and the possibility of the formation of cuts in the metal in castings. Urotropin is introduced into the composition to eliminate the crumbliness of the cured rods. At curing temperatures of the rods 250-330 ° C, it interacts with technical lignosulphonates with the formation of a gummy product with which the filler grains are held together and the crumbling of the rods is prevented. Tall oil is a plasticizer in the mixture and injecting it reduces the internal stresses that occur during the curing of the mixtures. 2 tabl C

Description

The invention relates to a foundry and can be used as a binder in the manufacture of casting cores and molds curable mainly by heat drying.

It is known to use in the foundry industry a binder consisting of technical lignosulfonates (LST), a USK-1 fixer and ammonium sulfate. However, when used in core mixtures, the rods have a high crushability and significant internal stresses

The closest to the proposed technical essence and the achieved result is a binder for casting cores and forms, including LST, a solution of bottom residues of fatty acids and activating additives in the form of asphalt-resinous compounds in the residue from the separation of narrow gasoline fractions (USK-1 forcer) active reagent (urea).

The disadvantages of this binder are significant internal stresses that occur in the rods during curing and cause microcracks in the bonding cuffs of the filler. At high temperatures in the process of pouring metal micro

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cracks go t in macrocracks, causing the formation of perforations.

The purpose of the invention is to improve the quality of the rods and shapes by reducing the internal stresses arising in them during curing of the binder, preventing crumbling and the possibility of the formation of metal gaps,

The proposed binder contains technical lignosulfonates, a solution of bottom residues of fatty acids and activating additives in the form of asphalt-resin compounds in the residue from the separation of narrow gasoline fractions, urotropine and tall oil.

An example of a solution of bottoms of fatty acids and activating additives in the form of asphalt-resinous compounds in the residue from the separation of narrow gasoline fractions can be USK-1 or SKT-10.

At hardening temperatures of rods 250-330 ° C, urotropine, interacting with LST, forms a resinous product that securely holds the filler grains, preventing the crumble of the hardened rods while maintaining their high strength.

Tall oil is a plasticizer; adding it to the mixture reduces the internal stresses that occur in the seaming cuffs of the filler during curing of the rods.

The binder composition is prepared as follows.

LST with a density of 1250-1300 kg / m3 is poured into the container and urotropin is loaded, the components are stirred until complete dissolution of urotropine. Then, tall oil is injected and, after stirring for 1-2 minutes, UCL-1 is poured. After stirring for 1-2 minutes, the binder is ready for use. The binder must be stored in a closed container and stirred before use.

It is possible to introduce the components directly in the process of preparing the core mixture. Then, in order to achieve higher strength characteristics of the mixture, it is prepared as follows.

A runner (quartz sand) and urotropin are poured into the runners, after mixing for 1-2 minutes LST and tall oil are successively introduced. After mixing the components for 10-15 minutes, pour USK-1, and mix the mixture for an additional 1-2

min The finished mixture is produced in a box and covered with plastic wrap. The term of use of the mixture is 8-10 hours.

It is possible either to introduce a pre-prepared binder composition into the mixture, or to prepare a mixture for making casting cores and molds with the binder composition components being sequentially introduced into it. However, the preliminary preparation of the binder composition provides higher strength properties of the rods due to the uniform distribution of the activator in the LST.

The compositions of core mixtures with the proposed binder (1,2,3) and known (A) are listed in Table 1, their technological properties are given in Table 2.

From table 2 it follows that the proposed

the binder ensures the reduction of internal stresses arising in the bonding cuffs of the filler (quartz sand) in comparison with the prototype, prevents crumbling of the rods while maintaining high indicators of their strength and ensures the production of castings without gaps .x

Claims (1)

Invention Formula Binder for the manufacture of casting cores and heat curing forms, including technical lignosulfonates, a solution of bottom residues of fatty acids and activating additives in the form of Asphalt-resinous compounds in the residue from the release of gasoline fractions and active reagents are characterized in that, in order to increase the quality of rods and shapes by reducing the internal stresses during curing of the binder, to prevent crumbling and the possibility of formation of perforations of the metal, as an active reagent it contains urotropin and additionally tall oil in the following ratio, wt.%: The solution of the bottoms of fatty acids and activating additives in the form of asphalt-resin compounds in the residue from the release of narrow bin Zine fractions8,33-46,66 Urotropin3,33-5,0 Tall tall oil 3,33-5,0 Technical lignosulfonates Else Table 1 Note. The numerator indicates the indicators of the properties for the mixtures in which they were injected complex, pre-cooked, binder, denominator - introduction complex binder components during mixture preparation. table 2