Metallurgy and Foundry Engineering
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ISSN 1230-2325
e-ISSN: 2300-8377
Issue Date
2015
Volume
Vol. 41
Number
No. 3
Description
Journal Volume
Metallurgy and Foundry Engineering
Vol. 41 (2015)
Projects
Pages
Articles
FTIR method in studies of the resol-type phenol resin structure in the air atmosphere over certain time intervals
(2015) Bobrowski, Artur; Grabowska, Beata
This paper presents the results of structural-type studies of resol phenolic resin used for the preparation of molding and core sands exposed to air. The FTIR study was carried out using a transmittance technique. Recorded changes in the IR spectra of resin can indicate a progressive polycondensation process, the consequences of which being changes in the aromatic rings of methylene bridges (among others).
Structural construction of hardeners with different hardening rates intended for geopolimer binder systems used for the preparation of moulding sands
(2015) Bobrowski, Artur; Grabowska, Beata; Kaczmarska, Karolina
The paper presents the results of structural investigations of hardeners with different hardening rate for geopolymer binder system Geopol, manufactured by the Sand-Team Company. Studies have shown that these hardeners have similar chemical structures and that the hardening rate of the binder depends on the proper selection of the proportions of the respective components.
Theoretical analysis of the AZ31 magnesium alloy deformation process by a modified method of angular extrusion
(2015) Bajor, Teresa; Krakowiak, Marlena; Berski, Szymon Arkadiusz
The paper presents the results of the numerical modeling of a chosen magnesium alloy deformation process by a modified method of angular extrusion (AE). The research was made using a die with a circular cross-section, where the channels were arranged at right angles relative to each other. The modification concerned the differing values of applied unit strain obtained by changing the material enter/exit diameter ratio. The extrusion process was analyzed for several temperature-velocity variants. The aim of this work was to determine the most favorable conditions of the extrusion process that result in the most uniform stress and strain distribution in the material.
An assessment of the effectiveness of physical curing methods of molding sand bonded by binders based on starch and aluminosilicates
(2015) Kaczmarska, Karolina; Grabowska, Beata; Drożyński, Dariusz; Kurleto, Żaneta; Szymański, Łukasz
In this study, the effectiveness of curing methods by conventional heating and innovative microwave curing were compared, based on the results of determining molding sand selected properties such as permeability, tensile strength, and wear resistance. The tested molding sand used for our research was a composition of silica sand with a commercial binder in the form of Albertine F/1 (Hüttenes Albertus). This binder is a mixture of water-swellable starch derivatives and aluminosilicates. Binding in the molding sand occurred via solvent evaporation from the samples (water).The obtained results showed a dependence of molding sand properties and selected methods of physical cure, especially after one and four hours of cured-sample storage. However, after 24 hours of sample storage (as apparent from the analysis of the obtained results), both curing methods used were almost equally effective, and marked differences in the molding sand properties were located in the range of measurement uncertainty. Using electromagnetic waves in the microwave range made it possible to significantly reduce the time of curing as well as the energy consumption of the drying process.
Mechanical properties and structure evolution of the AZ91 magnesium alloy after hot rolling and annealing
(2015) Sułkowski, Bartosz; Boczkal, Grzegorz
The AZ91 magnesium alloy was processed up to 87.5% of total thickness reduction in several thermodynamic routes, consisted of hot rolling and intermediate annealing. The hot-rolling process was performed at a high strain rate equal to 1.6 s−1 and at a temperature of 430°C. The intermediate annealing was performed at 430°C for 15 minutes after each route. It was found that, during hot rolling, the hardness of the material increased from 32 HV to 40 HV, and the structure investigations showed a huge amount of twins formed inside the grains (which were not observed after annealing). Tensile tests have shown strong anisotropy in mechanical properties of the “as-rolled” samples dependent onthe orientation between tension direction (TD) and rolling direction (RD). The samples with TD perpendicular to RD provedhigher ultimate tensile strength (UTS) and (on the other hand) worse plastic properties as compared to the samples with TD parallel to RD. The annealing has an effect on the reduction of mechanical properties anisotropy. X-ray investigations have shown texture changes from the basal type with the additional (0001) <1120> component for “as-rolled” samples to the texture with the main (0001) <1010> component for annealed samples. The texture changes had a great impact on the anisotropy of mechanical properties of the investigated AZ91 magnesium alloy.