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W. Fracz, F. Stachowicz, T. Trzepieciński and T. Pieją

Abstract

Formability of sheet metal is dependent on the mechanical properties. Some materials form better than others - moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another configuration. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. However experimental studies of formability of various materials have revealed basic differences in behaviour, such as the ”brass-type” and the ”steel-type”, exhibiting respectively, zero and positive dependence of forming limit on the strain ratio. In this study mechanical properties and the Forming Limit Diagram of the AMS 5599 sheet metal were determined using uniaxial tensile test and Marciniak’s flat bottomed punch test respectively. Different methods were used for the FLD calculation - results of these calculations were compared with experimental results

Open access

D. Woźniak, M. Głowacki, M. Hojny and T. Pieja

This article shows example result of computer simulations supporting production process of bearing housing of aircraft engine. Verification of both deep drawing process project and tools design were carried out using finite element models implemented in eta/Dynaform 5.8.1 system and LS-DYNA solver. Wrinkling and fracture of the material were the main phenomena subjected to the investigation on the way of numerical analysis. A number of computer simulations were carried out in aim to analyze the deformation and strain distribution in the final product, as well as to eliminate the mentioned defects. In addition the comparison of results of both industrial tests and computer simulation was done.

Open access

P. Maj, B. Adamczyk-Cieslak, M. Slesik, J. Mizera, T. Pieja, J. Sieniawski, T. Gancarczyk and S. Dudek

Abstract

Inconel 718 is a precipitation hardenable nickel-iron based superalloy. It has exceptionally high strength and ductility compared to other metallic materials. This is due to intense precipitation of the γ’ and γ” strengthening phases in the temperature range 650-850°C. The main purpose of the authors was to analyze the aging process in Inconel 718 obtained in accordance with AMS 5596, and its effect on the mechanical properties. Tensile and hardness tests were used to evaluate the mechanical properties, in the initial aging process and after reheating, as a function of temperature and time respectively in the ranges 650°-900°C and 5-480 min. In addition, to link the mechanical properties with the microstructure transmission microscopy observations were carried out in selected specimens. As a result, factors influencing the microstructure changes at various stages of strengthening were observed. The authors found that the γ’’ phase nucleates mostly homogenously in the temperature range 650-750°C, causing the greatest increase in strength. On the other hand, the γ’ and δ phases are formed heterogeneously at 850°C or after longer annealing in 800°C, which may weaken the material.

Open access

K. Żaba, M. Nowosielski, S. Puchlerska, M. Kwiatkowski, P. Kita, M. Głodzik, K. Korfanty, D. Pociecha and T. Pieja

The paper presents the research results of the mechanical properties and microstructure of the material in initial state and parts made from nickel superalloy Inconel®718 in the rotary forming process with laser heating. In the first step was carried out basic research of chemical composition, mechanical properties, hardness and microstructure of sheet in initial state. Then from the metal sheet, in industrial conditions, was made axisymmetric parts in the flow and shear forming with laser heating. Parts were subjected to detailed studies focused on the analysis of changes in the mechanical properties and microstructure in the relation to the material in initial state. The analysis was based on the tests results of strength and plastic properties, hardness, microstructural observations and X-ray microanalysis in the areas where defects appear and beyond. The results are presented in the form of tables, charts, and photographs of the microstructure.