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Characteristic of Cast Zn-Al-Cu Alloy Microstructure after Modification

Krupińska B., Krupiński M., Rdzawski Z., Labisz K., Król M.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 4 spec.

77--82

EN

Cast zinc alloys have similar properties to aluminium alloys. The differences are due to the lower melting point and higher density. Zinc has a density of 7.14 g/cm3, a melting point of 419.5°C and the boiling temperature of 906º C. In the temperature range from 150 to 200°C, zinc has good susceptibility to plastic deformation. It is also resistant to atmospheric factor influence, but is not resistant to acids. The main use of zinc alloy, is the production of thin-walled casts that require high precision. Zinc alloys are also used for die casting moulds, housings and covers as well as a variety of devices that are used in the precision industry, electrical engineering, automotive and construction industry. Properly performed chemical modification leads to improve of properties of the produced castings. Therefore it is very important to know how the cast structure with the change of the chemical composition by adding metallic modifiers to the liquid metal. In this work there was studied the effect of chemical modification of cast zinc alloy on the properties and microstructure of the alloys before and after modification. Modified alloys were prepared by adding modifiers in the range of 0.1% to 1% in form of Ti- Sr and B as aluminium master alloy and then cast into the metal moulds. Next the thermo-derivative analysis was performed of the modified Zn-Al-Cu alloy, the microstructure investigation was carried out using light microscopy and scanning electron microscopy with EDS X-ray microanalysis usage as well as hardness was measured of the modified Zn-Al-C alloys.

2

Badania przemysłowe nowej generacji mas modelowych

Karwiński A., Młodnicki S., Pabiś R., Robak I., Kubosz G.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 1s

25-32

PL

Masy modelowe miękkie stosowane obecnie w odlewnictwie precyzyjnym podlegają kilkukrotnemu zobiegowaniu w procesie produkcyjnym. Na dzień dzisiejszy nie została opracowana metodyka służąca określeniu stopnia zużycia masy i podjęciu decyzji o jej wycofaniu z produkcji jak również nie wypracowano skutecznej metody regeneracji masy zużytej. W artykule przedstawiono zakres przeprowadzonych badań oraz przyjętą metodykę postępowania w celu określenia możliwości regeneracji eksploatowanych mas miękkich oraz oceny właściwości technologicznych mas zużytych i mas poddanych regeneracji. W ramach prowadzonych badań sprawdzono możliwość regeneracji zużytej masy modelowej w warunkach przemysłowych oraz przedstawiono wyniki badań nad zastosowaniem metod instrumentalnych do określenia stopnia zużycia mas modelowych, poprzez ocenę ubytków komponentów mas w trakcie ich eksploatacji. Praca obejmuje także badania właściwości technologicznych stosowanych obecnie mas miękkich, innowacyjnej masy modelowej świeżej oraz masy poddanej kilkukrotnemu zobiegowaniu wraz z próbą oceny skuteczności procesu regeneracji i jego wpływu na parametry technologiczne masy.

3

Kinetics of hardening of ceramic layers applied in the investment patterns method

Zych J., Matysiak H., Michalski J.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 2

151-154

EN

The work presents results of investigations of a hardening rate of ceramic moulds applied in investment patterns method. During the studies, the original method based on the ultrasonic technique, and a novel testing routine were used. The course of hardening of single ceramic layers, and subsequently applied layers was determined. The investigations concerned ceramic mixtures with a binder based on water colloidal silica and Al2O3 matrix. The effect of ceramic layer thickness on its hardening at temperature; T = 23-24oC and, air relative humidity; RH = 45-55% was determined.

4

Efficiency of protective coatings on high creep resistant cast steel

Kochmańska A., Kubicki J.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 2

129-132

EN

This paper presents results of research of multilayer aluminium-silicon coatings. Aluminium-silicon coatings were created on high-temperature creep resist cast iron using slurry method in air atmosphere. These coatings protect equipment against hot corrosion in carburizing atmosphere at thermal shocks conditions. Various technological parameters of coatings manufacturing were applied. Main technological parameters were: temperature and time of annealing and Al-Si ratio in the active mixture. The structure of obtained coatings is three-zonal. Phase composition of two external zones ensures protection against carburizing, but these zones are not resistant to cracking. The cracks form as a result of thermal shocks. The internal zone of the coatings situated next to substrate compensates for differences of thermal expansion of the coating and the substrate. The cracks are stopped in the internal zone and do not propagate into the substrate material. Protective efficiency of the coatings at carburizing conditions with thermal shocks was determined. Structure of the coatings before and after carburizing and thermal shocks is described in present paper. Thickness, chemical composition (EDS) and phase composition (XRD) of the coatings are determined. Correlation between the coatings structure and depth of carburized layer was determined.