Wyniki wyszukiwania - BazTech

1

Study of the Influence of Additions on the Formation of Microstructure of Al-Zn-Mg-Cu Alloys

Pisarek B. P., Czekaj E., Pacyniak T.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

39--44

EN

The article presents the investigations of 7xxx aluminium alloys performed by the method of thermal and derivational analysis. The studies made it possible to identify the effect of the changes in the Cu concentration, the total Zn and Mg weight concentrations and the Zn/Mg weight concentration ratio on their crystallization process: the cooling as well as the kinetics and dynamics of the thermal process of cooling and crystallization. Metallographic studies were performed on the microstructure of the examined alloys and their HB hardness was measured. The evaluation of the changes was presented in reference to the model alloys EN AW-7003 and EN AW-7010, whose microstructure under the conditions of thermodynamic equilibrium are described by the phase diagrams: Al-Zn-Mg and Al-Zn-Mg-Cu. The performed investigations confirmed that the hardness HB of the examined alloys is mainly determined by the reinforcement of the matrix αAl by the introduced alloy additions and the presence of phases Θ(Al2Cu) and S(Al2CuMg) rich in copper, as well as η(MgZn2), in the examined alloys' microstructure. The increase of the amount of intermetallic phases precipitated in the microstructure of the examined alloys is caused, beside Cu, by the characteristic change of Zn wt. concentration and Mg. It was proposed that the process of one-stage thermal treatment of the examined alloys be introduced at a temperature of up to tJ-20 °C, which will prevent the exceedance of the solidus temperature.

2

Influence of the Home Scrap Content on the Service Life of Equipment Used in High Pressure Die Casting of AZ91 Alloy

Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

173--176

EN

The results of estimation of home scrap addition in charge influence on durability and wear of casting instrumentation life in the high-pressure casting technology using the hot chamber machine of alloy of AZ91 are presented. The wear of the following elements of the casting instrumentation so-called "casting set" as: syphon, plunger, sliding-rings, nozzle and injection moulding nozzle was estimated. A wear was estimated quantitative by registering the number of mould injections for different charges to the moment of element damage supervision. A damage had to be at such level that liquidated an element from further exploitation and necessary was an exchange on new or regeneration. In a final result allowed it the detailed determination of durability of the applied rigging elements in dependence on the type of the applied type of melt. It is noticed, that together with the increase of home-scrap participation in the charge wear of pressure machine instrumentation elements increases.

3

Structure and properties of new ecological copper alloys for fittings

Juszczyk B., Kulasa J., Cwolek B., Malec W., Wierzbicki Ł.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

97--102

EN

The article presents the results of studies concerning the selection of the chemical composition of the new ecological copper alloys for fittings. It was analyzed, among other things, the impact of the content of bismuth, aluminum, iron and boron. Their solidification process was characterized on the grounds of thermal and derivative analysis (TDA). Also the microstructure and mechanical properties were analyzed. Casting properties were determined by the castability spiral test. It was found that zinc is an essential component of the tested group of alloys, determining the course of their crystallization, phase composition and microstructure. There was no significant effect from the other elements on the course of crystallization. The obtained results revealed that bismuth is the element of the strongest impact on the castability changes. The formulated alloys surpass the commonly used standardized alloy intended for components of fittings, namely MO59, in terms of casting and mechanical (hardness) properties.

4

Effect of two-stage isothermal annealing on microstructure CuAl10Fe5Ni5 bronze with additions of Si, Cr, Mo, W and C

Pisarek B. P.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

187--194

EN

The aim of this study was to investigate the effect of a two-step isothermal annealing respectively at 1000 ˚C for 30 min, then at the range of 900÷450 ˚C increments 50 ˚C on the microstructure CuAl10 Ni5Fe5 bronze with additions of Si, Cr, Mo, W and C, cast into sand moulds. The study concerned the newly developed species, bronze, aluminium-iron-nickel with additions of Si, Cr, Mo, W and C. In order to determine the time and temperature for the characteristic of phase transitions that occur during heat treatment of the test method was used thermal and derivation analysis (TDA). The study was conducted on cylindrical test castings cast in the mould of moulding sand. It was affirmed that one the method TDA can appoint characteristic for phase transformations points about co-ordinates: τ (s), t (˚C), and to plot out curves TTT for the studied bronze with their use. It was also found that there is a five isothermal annealing temperature ranges significantly altering the microstructure of examined bronze.

5

Lost wax process – mould properties

Trytek A., Nawrocki J., Sarek D.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

427--430

EN

Paper present results of moulds properties as follow: permeability and shell Module of Rupture (MOR). Measurement and tests have been made on moulds from two different mould systems: water and alcohol. Mechanical properties measurement was made on standard samples. Permeability measurements required preparing special shape samples [4]. All scope of tests have been realized in WSK ”PZL-Rzeszów” S.A. Results showing permeability and mechanical properties of two mould systems in function of quantity layers.