Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia:

I. O. Leushin, Dr. Eng., Professor, Head of the Dept. of Metallurgical Technologies and Equipment, e-mail: igoleu@yandex.ru
A. N. Grachev, Cand. Eng., Associate Professor, Dept. of Metallurgical Technologies and Equipment, e-mail: alexgra76@mail.ru
L. I. Leushina, Cand. Eng., Associate Professor, Dept. of Metallurgical Technologies and Equipment, e-mail: kafmto@mail.ru
P. M. Yavtushenko, Postgraduate Student, Dept. of Metallurgical Technologies and Equipment

Liquid, or liquid, self-hardening mixtures successfully combine the properties of a liquid, which make it possible to manufacture casting molds and cores by free pouring the mixture in a gravitational field without applying external influences to it, and the ability to independently solidify in air for a certain time and ensure residual gas permeability of the casting mold, or rod up to 400 units. However, until now, such mixtures have not been widely used in practice due to their insufficient manufacturability. In this work, the task was to find the composition and test a self-hardening liquid mixture with improved manufacturability for the production of molds and cores of steel casting. The expected technical result of its solution was the provision of high compressive strength and survivability with minimal crumbling of the mixture without reducing its fluidity and gas permeability. The composition of the mixture is proposed, including a refractory filler, a binder, a hardener, a foaming agent, a foam stabilizer and water, in which quartz sand acts as a refractory filler, a binder is water glass, a hardener is ethylene glycol acetate, a foaming agent is a synthetic detergent from the group of alkyl sulfates, and in as a foam stabilizer - a ready-made organosilicon binder. The roles of each of the components and their influence on the complex of technological properties of the mixture are described. The results of experimental work carried out to assess the effectiveness of the proposed solution are presented. The results of the experiments showed that the self-hardening liquid mixture proposed by them can be successfully used for the manufacture of casting molds and cores of steel casting for critical purposes.

1. Reichert M., Schulte E. Neues Verfahren für anorganisch gebundene Gießereisande. Giesserei. 2021. No. 5. pp. 56–58.
2. Sander V. Wo die metallurgischen Zusatzstoffe in Gießereien herkommen? Giesserei. 2021. No. 4. pp. 62–65.
3. Lechner Ph., Ettemeyer F., Volk W. Mechanisches Bruchmodell für wasserglasgebundene Kerne. Giesserei. 2021. No. 3. pp. 24–30.
4. Piterek R., Steller I., Rennings T. Formstoffforum in München. Giesserei. 2020. No. 3. pp. 20–24.
5. Tkachenko S. S., Krivitskiy V. S., Muravyev Yu. N., Kolodiy G. А. Revival of shaping technology in machine tool industry based on inorganic components. Stankoinstrument. 2018. No. 1 (010). pp. 62–67.
6. Tkachenko S. S., Kolodiy G. А., Znamenskiy L. G., Ermolenko А. А. Cold-hardening mixtures based on an inorganic binder: state of the art and development prospects (inorganic versus organic). Lityo i metallurgiya. 2018. No. 2 (91). pp. 16–22.
7. Kidalov N. А., Grigoryeva N. V., Orlova А. V. Study of the effect of alkalized technical lignosulfonates on the physical, mechanical and technological properties of liquid glass mixtures. Izvestiya Volgogradskogo gosudarstvennogo tekhnicheskogo universiteta. 2021. No. 7 (254). pp. 41–45.
8. Milochkina D. I. et. al. Liquid self-hardening mixture. USSR author’s certificate No. 837551. Published: 15.06.1981. Bulletin No. 22.
9. Prozorin S. I. et. al. Liquid self-hardening mixture for the manufacture of molds and cores. USSR author’s certificate No. 1360869. Published: 23.12.1987. Bulletin No. 47.
10. Boldin А. N., Davydov N. I., Zhukovskiy S. S. et. al. Foundry molding materials. Moscow: Mashinostroenie, 2006. 507 p.
11. Doroshenko S. P., Avdokushin V. P., Rusin К. Molding materials and mixtures. Kiev: Visha shkola, 1990. 415 p.
12. Zinchenko Yu. А. Study of a liquid self-hardening mixture for steel casting molds in order to optimize its composition. Vestnik DGTU. 2010. Vol. 10. No. 2 (45). pp. 258–265.
13. Ponomarenko О. I., Karateev А. М., Evtushenko N. S., Berlizeva Т. V. Experience in the manufacture of castings based on liquid glass using ATsEG. Metall i lityo Ukrainy. 2010. No. 11. pp. 20–23.
14. Rodina Т. А. Flotation reagents. Blagoveshchensk: Izdatelstvo AmGU, 2015. 36 p.
15. Repyakh S. I. Technological foundations of investment casting. Dnepropetrovsk: Lira, 2006. 1056 p.
16. GOST 13078. Sodium silicate solute. Specifications. Introduced: 01.01.1982.
17. GOST 2138–91. Moulding sands. General specifications. Introduced: 01.01.1993.
18. Koryshev A. N. et. al. Liquid self-hardening composition for making casting molds and cores. Patent RF No. 2262409. Published: 20.10.2005. Bulletin No. 29.
19. GOST 23409.7–78. Molding sands, molding and core sand mixtures. Methods for determination of compressive, tensile, bending and shearing strength. Introduced: 01.01.1980.
20. GOST 29234.11–91. Molding sands. Methods for determination of gas permeability. Introduced: 01.01.1993.
21. GOST 23409.9–78. Molding and core sand mixtures. Methods for determination of friability. Introduced: 01.01.1980.
22. GOST 977–88. Steel castings. General specifications. Introduced: 01.01.1990.