Water gas saturation as a lever for controlling the level of properties of frozen foundry molds
DOI:
https://doi.org/10.15407/steelcast2024.01.003Keywords:
Mixture, form, water, gas, solubility, survivability, strengthAbstract
The purpose of the work is to increase the survivability of sand-clay forms that freeze in equipment without the use of liquefied gases.
Quartz sand 1K3O3016, bentonite clay BS2T2, kaolin clay KS2T2, tap water, carbonated water and degassed (boiled) water were used in the research. Flowability was determined according to GOST 23409.9, compressive strength — GOST 23409.7, gas permeability — GOST 29234.11.
In order to achieve the specified level of the main parameters of sand-clay mixtures frozen at –15 °С with a simultaneous increase in the survivability of frozen casting molds and rods up to ~18 min, it is most appropriate to use a mixture of 5 % bentonite clay of the BS2T2 brand and 5 % of degassed (boiled) water with clay activation in such water as part of the mixture for 24 hours. At the same time, the use of KS2T2 kaolin clay as part of mixtures is impractical, since mixtures with such clay do not meet the requirements for molding and core mixtures.
Molding mixtures consisting exclusively of sand and water are not suitable for the production of casting molds and rods due to high flowability. To increase the strength and reduce the flowability, it is necessary to use a mixture of sand, water and clay for the production of frozen molds and rods. Addition of bentonite (BS2T2) or kaolin (КS2Т2) clay to sand and water leads to a decrease in the flowability of frozen mixtures and an increase in their strength. Frozen at –15 °C mixtures with a kaolin clay content of up to 7 % (by mass) and 5 % (by mass) of tap water are characterized by increased flowability, which makes it impossible to use them as a molding or core mixture. When adding 5 % of bentonite clay BS2T2 swollen with degassed water to quartz sand, the flowability of the frozen mixture becomes less than 0.1 %, the gas permeability reaches 129 units, and the compressive strength exceeds 4.0 MPa, which meets the requirements for molding and rod mixtures. The gas saturation of water is a powerful lever in the system of controlling the level of properties of frozen casting molds, which include quartz sand and swollen bentonite clay.
References
Solonenko, L., Prokopovitch, I., Repyakh, S., Sukhoi, K., Dmytrenko, D. (2019). System analysis of modern areas of increasing environmental and sanitary hygienic safety of using cold hardening mixtures in foundry. Proceedings of Odessa Polytechnic University, 1(57), 90-98. https://doi.org/10.15276/opu.1.57.2019.11
Kukuy, D.M., Skvortsov, V.A., Andrianov, N.V. (2011). Theory and technology of foundry production. In 2 parts. Part 1. Molding materials and mixtures. Minsk: New knowledge; Moscow: INFRA-M. 384 р. [in Russian].
Solonenko, L.I., Usenko, R.V., Belyi, A.P., Repyakh, S.I. (2019). Characteristics of some casting methods and mixtures of disposable molds and cores for castings weighing up to 300 kg. Perspectives of world science and education: Abstracts of I International Scientific and Practical Conference, Osaka, Japan, 2-4 October 2019. Osaka, 202-210 [in Russian].
Tao, Y., Zou, W., Jia, J., Li, W., & Cremer, D. (2016). Different ways of hydrogen bonding in water – why does warm water freeze faster than cold water? Journal of Chemical Theory and Computation, 13(1), 55-76. https://doi.org/10.1021/acs.jctc.6b00735
Shinskii, O.I., Lysenko, T.V. & Solonenko, L.I. (2016). The influence of composition, dispersity and temperature of cooling mold materials on the mechanical properties of low-temperature forms. Metal and Casting of Ukraine, 11-12 (282-283), 47-51 [in Russian].
J. Shan Zhongde, Yang Hao Qin & Shi Jianpei (2022). Large complex sand freezing mold, low temperature molding and joint production method with undercooling control. (China Patent No. CN113579161B). Nanjing University of Aeronautics and Astronautics.
N. Gundolf Dipl Ing Helering (1979). Foundry molds made by freezing wet sand – the sand is cooled by a liquid, nitrogen is mixed with the wet sand and driven into a flask. (German Patent No. DE2909839A1). Linde GmbH.
Bakshi, B., Singh & Emil, Jespersen (1985). Method for making frozen molds for casting. (Canadian Patent No. CA1183320A). Dansk Industri Syndikat AS.
Shan Zhongde, Yang Hao Qin & Dai Yufeng (2021). A method of preparing a mold from a mixture of frozen sand and short fibers. (China Patent No. CN113560486A). Nanjing University of Aeronautics and Astronautics.
Hoshiyama, Y., Nakashima, K., & Matsumoto, H. (2020). Simultaneous fabrication of multiple castings using frozen mold casting method. Defect and Diffusion Forum, 405, 75-79. https://doi.org/10.4028/www.scientific.net/DDF.405.75
Yang, H., Shan, Z., Yan, D., Shi, J., & Liu, Q. (2023). Research on forming method of additive manufacturing of frozen sand mold. Heliyon, 9(8), 1-5. https://doi.org/10.1016/j.heliyon.2023.e19340
Shan Zhongde, Liu Fenglandun & Dong Xiaoli (2016). A variation of the containerless casting process is formed from frozen sand. (China Patent No. CN105665637B). Center for Advanced Manufacturing Technology of Chinese Academy of Engineering Science and Technology.
Shang Zhongde, Liu Fenglandong & Dong Xiaoli (2018). A kind of frost sand mold production process of containerless casting. (China Patent No. CN105665637B). Beijing Institute of Light Quantitative Science and Research.
Zamyatin, N.I., Lysenko, T.V., Kreitser, K.A., Bondar, A.A. (2013). Production of castings in frozen molds under low pressure. East European Journal of Advanced Technologies. 2/5(62), 50-54 [in Russian].
Doroshenko, V.S. (2017). Ice models in liquefied fermentation of metal-producing substances are a technology based on the “just add water” method. Svitoglyad, 1(63), 62-69 [in Ukrainian].
Doroshenko, V.S. (2017). Research structure for the development of ice casting technology using a number of features and natural phenomena. Casting Processes, 1, 39-46 [in Russian].
Shinsky, O.I., Moskovka, V.I., Shevchenko, V.A. (1984). One-piece frozen model for low temperature molding (A.S. No. 1121089 USSR), publ. 1984 [in Russian].
Shi, J., Shan, Z., Yang, H. (2023). Experimental and modeling investigation of freezing behavior for frozen sand molds. International Journal of Heat and Mass Transfer, 215, 124499. https://doi.org/10.1016/j.ijheatmasstransfer.2023.124499
Solonenko, L.I., Repyakh, S.I. (2019). Flaking of liquid glass molds and rods. New materials and technologies in machine-building: materials of the XI International Scientific and Technical Conference (Kyiv, May 30-31, 2019). Kyiv: KPI im. Igor Sikorsky, 178-179 [in Russian].
Downloads
Published
Issue
Section
License
Copyright (c) 2024 Metal and Casting of Ukraine
This work is licensed under a Creative Commons Attribution 4.0 International License.
