Nizhniy Novgorod State Technical University (Nizhniy Novgorod, Russia):

A. N. Grachev, Cand. Eng., Associate Prof., Deputy head of the chair “Metallurgical equipment and technologies”, e-mail: mto@nntu.ru
I. O. Leushin, Dr. Eng., Prof., Head of the chair “Metallurgical equipment and technologies”, e-mail: igoleu@yandex.ru
L. I. Leushina, Cand Eng., Associate Prof.

Exothermic cores are used for rising the efficiency of operation of casting feeders and for their weight lowering. When casting feeder is covered by exothermic mixture, it is heated up owing to liquid metal. As a result, feeder’s work time increases and shrink corruption decreases. At present time Russian factories use basically foreign and expensive exothermic cores for steel and high-strength cast iron castings. It is proposed in the article to use wastes of thermal production (slurry of the quenching tanks and slurry of nitre baths) to lower price of feed cores and to develop recycling technologies. The slurry of the quenching tanks contains about 70% mass. of ferric oxide and play a role of exothermic mixture’s oxidant. The slurry of nitre baths is an additive, which enable fast mixture’s inflammation, because of about 80% mass. of NaNO₃ and KNO₃. Aluminium powder is an oxidizer of the proposed mixture, and silica sand is a mixture filler. Binder composition consists of water glass and ethylene glycol acetates as a hardener. To exclude moulding operation, mixtures convert in liquid self-hardening condition by introduction of surface-active material (water solution of triethanolamine sulphate). Developed exothermic mixtures have displayed their effectiveness while testing on operating casting factories.

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