Realization of Internal Reserves of Sand Form by Dual Use of Model-Forming Materials in Foundry

Processy litʹâ, 2019, Tom 134, №2, p.35-39

Abstract

Received 10.12.2018

UDK 621.74.045.072.2

The urgency of the development of the technology of sand mold, as an important component of foundry processes, is based on the fact that in such molds produce up to 80 % of the tonnage of castings, including special types of casting in such molds. The capacity of the equipment, area and personnel of foundries on 60−70 % relate to the molding processes, including mixing and core manufacturing. Pollution due to fault mold can reach 80 %. Significant potential for the development of molding technology is the improvement of the processes of casting metal into molds from loose sandy mixtures without binder, in particular, in the Lost Foam Casting process. The concept of improving the processes of casting metal in the mold of granular sand using the dual use of pattern and molding materials is presented, and examples of such an application are given. The use of loose molding compounds for rapid cooling of the casting, including heat treatment, makes it possible to strengthen its metal and shorten the duration of cooling of castings in the mold, which leads to an increase in the productivity of foundries without increasing the number of tooling and mold filler. Methods of isothermal quenching (austempering) from a hot state of castings from iron-carbon alloys exclude heating and aging for their austenization, which reduces the time and energy consumption of obtaining products with a bainitic structure, and also, in fact, corresponds to the concept of the implementation of internal reserves of both sand mold and cast metal. Сasting ice patterns are not only suitable for the reproduction of castings with high accuracy, but also take part in the hardening of sand mixtures by the method of cold hardening by forming crystalline hydrates in them, and also contribute to the environmental and efficiency of foundry processes by replacing conventional organic pattern and molding materials with inorganic ones.