Manufacture of foundry forms by steam-microwave hardening by models from frozen sand-water mixtures

Шрифт:
222

https://doi.org/10.15407/steelcast2021.01.038

Met. litʹe Ukr., 2021, Tom 29, №1, P. 38-45

L.I. Solonenko1, PhD (Engin.), Associate Professor at the Department of Technology and Management of Foundry Processes,e-mail: solonenkoli14@gmail.com, https://orcid.org/0000-0003-2029-8044
S.I. Repyakh2, Dr. Sci. (Engin.), Professor at the Department of Foundry, e-mail: 123rs@ua.fm, https://orcid.org/0000-0003-0203-4135

1Odessa National Polytechnic University (Odessa, Ukraine)
2National Metallurgical Academy of Ukraine (Dnipro, Ukraine)

Received 22.11.2020

UDK 621.744

The article investigates the possibility of using (combining) a frozen sand-water model, which is a source of steam when heated, and steam-microwave curing to obtain complex configurations of volume-closed forms, as well as the influence of mass water content in the sand-water model on the surface quality of the obtained three-dimensional closed molds.
The studies used quartz sand brand 1K2O202, distilled water, sodium liquid glass with a silicate modulus of 2.8–3.0 and a specific gravity of 1.43–1.46g/cm3, clad quartz sand 1 % liquid glass (by weight, more than 100 % sand) dried in air and in the field of microwave radiation. The temperature was measured with a precise thermometer Greisinger G 1700 with an accuracy of 1 °C, weighing was performed on electronic scales brand MH200 with an accuracy of 0.01 g. Form structuring, drying of clad sand, heating of weighed portions of water, a mixture of water and sand, frozen portions of a mixture of water and sand were carried out in a microwave oven with a nominal magnetron power of 900 W and a radiation frequency of 2.45 GHz.
The analysis of the obtained results shows that the combination of steam-microwave curing and the model of frozen sandwater mixture allows to obtain complex configurations of volume-closed forms. Manufactured molds according to this technical solution immediately after manufacture are suitable for use because they contain virtually no moisture and, accordingly, virtually no gas. The proposed method can produce molds of any complexity, and their limitations in weight and size will be due solely to the size of the working space of the used freezer and microwave.
It is established that the duration of water evaporation in the field of microwave radiation increases with increasing mass of water that evaporates, and largely depends on the material of the medium from which it evaporates and its initial temperature. 
For the manufacture of volume-closed forms, frozen models should be made from a mixture of quartz sand and 5–10 % of water (by weight, over 100 % sand). The proposed method of manufacturing three-dimensional closed molds is quite technological and can be recommended for the production of small castings from alloys based on iron, copper, aluminum for general engineering purposes in terms of single and small-scale production of castings.

Keywords: Mold, sand-liquid glass mixture, steam-microwave curing, frozen model, liquid glass, sand, water.

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