Browsing by Subject "cooling rate"

Now showing 1 - 6 of 6

Access status: Open Access ,
Design of a solidification rate measurement experiment for cast steel in molds made of different sands using computer simulation
(AGH University Press, 2025) Mordyl, Natalia; Jakubski, Jarosław; Żak, Paweł Leszek
This article presents the design process of the casting technology for a step-shaped casting made of steel using simulation tools. A series of proposals for gating and feeding systems were simulated in the MAGMASoftÂ® software. Results of numerical simulations allowed the Authors to select the casting technology which allows defect-free casting to be obtained. A numer ical analysis of the cooling rate of a step-shaped casting made of GX70CrMnSiNiMo2 tool steel with a 5% Ti addition was carried out for the selected manufacturing technology. Due to the nature of the material used and the extended presence of martensite during cooling, in-mold hardening of the casting may occur. The simulations showed that the type of molding material affects the cooling rate, which is confirmed by the analysis of cooling curves and the morphology of shrinkage po rosity. The analysis of solidification rates provides a valuable starting point and basis for subsequent research stages, taking into account the actual properties of the molding sands and the phase transformations occurring in the selected steel type. The casting technology design, which ensures the production of sound casting, was developed as part of this study. A series of simulations using different molding materials confirms the significant impact that the choice of mold material has on the casting solidification and cooling process.
Access status: Open Access ,
Grain-size prediction model in aluminum castings manufactured by Low-Pressure technology
(AGH University of Science and Technology Press, 2018) Fernández-Calvo, Ana Isabel; Lizarralde, Ibon; Sal, Elisa; Rodríguez, Patxi; Ochoa de Zabalegui Pereda, María Edurne; Cia, Igor; Rios, Ariane
The grain refinement in a real casting manufactured by Low Pressure Die Casting (LPDC) such as wheels and steering knuckles depends on the grain-refinement potential of the metal and the geometry of the part/process parameters. For this study, the effect of the cooling rate on the AlSi7Mg alloy with different metal qualities in terms of grain refinement was tested. The grain size has been metallographically evaluated in cylindrical test pieces and in the real wheels and steering knuckles manufactured at the Mapsa and Fagor Ederlan foundries. The Thermolan®-Al system has been used to evaluate the nucleation potential in terms of grain size on a standard cup. The grain size has been modeled taking into account the effect of the cooling rate measured in the center of the cylindrical test parts and the different grain-size potential. Different grades of refinement have been tested. The grain size measured in a real casting (wheel and steering knuckle) was used to calibrate the model for a real part in LPDC for different grain-size potential.
Access status: Open Access ,
Influence of cooling rate on the structure and damping properties of the AlSi6Cu4 alloy
(AGH University Press, 2025) Piwowarski, Grzegorz; Ogrodnik, Mateusz
The investigated alloy was cast as a shaft into seven casting molds. Casting molds made of different materials were char acterized by different abilities to conduct heat from the sample. This property significantly influenced the cooling rate of the sample casting from the AlSi6Cu4 alloy. The highest cooling rate was achieved in a steel mold at 25°C and the lowest in a mold made of insulating mass. Different cooling rates significantly influenced the structure of the alloy. Different grain sizes were obtained and the morphology of the microstructure components changed. At the highest cooling rate of 16.63 K·s?1, a grain with an average size of 0.58 mm was obtained. However, in the mold with the lowest cooling rate of 0.36 K·s?1, the average grain size was 3.76 mm. Changes in the structure of the alloy also influenced its damping prop erties. The tested values f the vibration damping coefficient ? indicated that the AlSi6Cu4 alloy cooling with the highest cooling rate has the highest value of damping coefficient. This is influenced by the grain size and shape of the silicon pre cipitates. The refinement structure and fragmented components effectively disperse the vibration wave in the structure of the casting alloy.
Access status: Open Access ,
The effect of rapid cooling on the corrosion resistance of as-cast aluminium alloy 5052
(AGH University of Science and Technology Press, 2017) Szklarz, Zbigniew; Krawiec, Halina; Rogal, Łukasz
The effect of rapid cooling by the vacuum suction casting method (VSC) on the microstructure and electrochemical response of the as-cast 5052 aluminium alloy is presented. The VSC method allowed us to obtain massive samples with a very high cooling rate (10$^{2}$ - 10$^{3}$)°C/s. The microstructure of the quick-cooled sample (QC) has been significantly changed. Finer grains and more-homogeneous intermetallic phase distribution has been observed. Corrosion potential (OCP) and polarization measurements (LSV) revealed a higher activity of the QC alloy than ingot (IN), which leads to a denser and thicker corrosion-product formation on the surface. Electrochemical Impedance Spectroscopy (EIS) indicates higher resistance values, which suggests a greater thickness of the corrosion products.
Access status: Open Access ,
The influence of cooling rate on the damping characteristics of the ZnAl4Cu1 alloy
(AGH University Press, 2022) Piwowarski, Grzegorz; Gracz, Beata
The paper presents the results of damping coefficient tests on the ZnAl4Cu1 alloy (ZL5). The damping coefficient has been calculated on the basis of specimen measurements obtained with the use of the signal echo method. The method consists in passing an ultrasonic wave through the tested material. The ultrasonic wave from a transmitting and receiving head passes through a specimen, bounces off its bottom surface and comes back to the measuring head in the form of a signal echo. The difference in the signal intensity between the first and the second echo in relation to the distance travelled by the ultrasound wave is avalue of the material's damping characteristics. The specimens were cast into three molds made of different materials, i.e. green sand, plaster and metal. The thermophysical properties of these materials are different, affecting the rate of heat absorption from the cast. Three series of specimens have been obtained which have different cooling rates. The specimens were then subjected to ultrasound and microscopic tests to assess the alloy structure. The internal alloy structure affects its damping properties to a great extent.
Access status: Restricted ,
Wpływ szybkości chłodzenia na mikrostrukturę żeliwa wysokowanadowego
(Data obrony: 2016-01-26) Lewicki, Bartłomiej
Wydział Odlewnictwa