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Kinetics of the Binding Process of Furan Moulding Sands, Under Conditions of Forced Air Flow, Monitored by the Ultrasonic Technique

Matonis Natalia, Zych Jerzy

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

93--98

EN

The paper presents the results of research on the kinetics of the binding process of self-hardening moulding sands with an organic binder under conditions of forced air flow at various pressure values. Three moulding sands made using urea-furfuryl resin Furanol FR75A technology were studied. The moulding sands were prepared on a base of quartz sand with an average grain size of dL = 0.25, 0.29 and 0.37 mm, with permeability values of 306, 391 and 476 m2108Pa x s (for ρo = 1.60, 1.60 and 1.61 g/cm3 , respectively). The research was conducted for a resin content of 1% with a constant proportion of hardener to resin, which was equal to 50%. Samples of the tested moulding sands were blown with air at pressures of 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 bar. The kinetics of the hardening process was monitored using ultrasound technology, according to a previously developed methodology [1]. The research was carried out on an ultrasound testing station equipped with a temperature chamber and an airflow reducer. The tests were conducted at a temperature of 20°C, and of the air flow pressure on the changes in ultrasonic wave velocity in the hardening mouldins sand as a function of time, the kinetics of the hardening process, and the degree of moulding sand hardening were determined. Additionally, the influence of the moulding sand permeability on the course of the hardening process at a constant air flow pressure was determined.

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Plasticity Changes of Moulding Sands with Chemical Binders Caused by Increasing the Hardening Degree

Matonis N., Zych J.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

71--76

EN

The results of investigations of plasticity of moulding sands with binders obtained by measuring deflection angles in the single point bend test in dependence on their hardening degree are presented in the hereby paper. Shaped samples made of moulding sands obtained in the technology with urea-furfuryl resin Furanol FR75A and in the technology with water glass, were subjected to various tests. Shaped samples were made on the quartz matrix of a medium grains size 𝑑𝑙=0,29 𝑚𝑚. Investigations were performed for the resin content being 1% and 2%, at a constant proportion of a hardener versus resin - equal 60%. In the case of sands from the technology with water glass, investigations were performed for 3.5% of water glass versus sand matrix and 0.35% of Flodur. Plasticity tests were carried out with using the strength machine with a continuous recording of a sample deflection value. Measurements of deflection angles values in the bend test were performed on a series of simultaneously made samples at constant time intervals from the moment of their making. To determine the sand hardening degree the ultrasound technique was applied, according to the previously developed methodology [1]. Every time from the obtained results the characteristic of the growing stress as a function of deflection was prepared (𝜎). In addition, for the tested group of moulding sands, empirical relationships between the maximum deflection angle (αmax) in the bend test and the hardening degree were determined (Sx): α = f(Sx).

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Badania, metodą nieniszczącą, procesu wiązania mas szybkoutwardzalnych przedmuchiwanych gazami

Zych J.

Archiwum Odlewnictwa

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2003

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R. 3, nr 10

297--306

PL

W pracy przedstawiono wyniki badań techniką ultradźwiękową procesu wiązania mas ze spoiwami chemicznymi przedmuchiwanych gazami. W pracy prezentowane są wyniki badań mas z alkaliczna żywicą fenolową utwardzaną CO2. Badania dotyczą kinetyki procesu oraz określenia wpływu ziarnistości osnowy, przepuszczalności i ciśnienia gazu na szybkość narastania warstwy utwardzonej masy. Badania mają charakter nieniszczący, a ich wyniki mogą być wykorzystane dla praktyki przemysłowej.

EN

In the work the results of ultrasonic investigation of the process of the chemical bounded moulding sand purged with gases setting are presented. Presented results concern the moulding sands based on an alkaline phenolic resin hardened with CO2. The kinetics of the process, and the relation between: the matrix granulation, the matrix permeability, a gas pressure, and the rate of growing of the layer of hardened moulding sand are studied. The investigations are non-destructive, and obtained results can be employed in the factory practice.