Volume III (2015)
The effectiveness of recrystallization high carbon steel with regard to the condition of material
Written by Dominika Grygier
Published: 07 December 2015
Abstract: The main aim of the studies presented in paper was to optimize the parameters of the recrystallisation annealing process used in the course of cold plastic working of high carbon steel for patented wires. Object of the research described in the work was eutectoid steel of 0,8% content of C designated for production of colddrawn wires applied for reinforcement of car tires, hoses and ropes. The results of tests show that the condition of the material and mainly degree of plastic deformation has a clearly influence on the effectiveness of pearlitic steel recrystallisation.
Keywords: recrystallisation, pearlitic steel, annealing, cementite
The influence of post-process operations on the mechanical properties of titanium alloy Ti-6Al-7Nb, produced by selective laser melting
Written by Michał Karoluk, Edward Chlebus
Published: 29 September 2015
Abstract: Even though selective laser melting (SLM) has been available for more than a decade, during few last years the interest in this technology has grown extremely. SLM technology allows to fabricate fully functional and complex metal objects, layer by layer, via selective melting of material using laser beam. However, producing object by melting thin layers of material causes conditions of fast heat removal. This phenomenon leads to equilibrium microstructures, accompanied by the residual stresses which cause the decrease of mechanical properties. The following paper presents the result of research in the field of the influence of the post-process operations, such as machining and heat treatment, on the mechanical properties of alloy Ti-6Al-7Nb build by SLM.
Keywords: selective laser melting, SLM, post-process operations, titanium alloy, Ti-6Al-7Nb
Process parameter optimization of Laser Micrometallurgy of AZ31 alloy
Written by Andrzej Pawlak, Edward Chlebus
Published: 18 September 2015
Abstract: This paper presents process optimization results of laser powder micrometallurgy of AZ31 alloy, for eliminating porosity in melted material. Full factorial design of three factors at three levels was conducted, and the influence of laser beam power, point distance and exposure time was examined.
Keywords: SLM, magnesium alloy, Design of Experiments, porosity
The effectiveness of spheroidization pearlitic steel with regard to the degree of plastic deformation
Written by Dominika Grygier, Włodzimierz Dudziński, Gregory Gerstein, Florian Nürnberger
Published: 25 May 2015
Abstract: Pearlitic steels containing from some 0,8 to 0,95% C belong to the group of unalloyed steels of the quality class destined for cold drawing or rolling, they find application mainly as wires used for reinforcement of tires, hoses or rope production. However this group of steels characterized low machinability, as a consequence of presence hard plates of cementite, the intervention ameliorative this property is spheroidizing annealing. The object of the tests presented in paper was wires of pearlitic steel obtained after the successive stages of cold plastic working. The aim of the tests was to show that the condition of the material and mainly degree of plastic deformation have a clearly influence on the effectiveness of pearlitic steel spheroidization.
Keywords: Pearlitic steel, annealing, cementite
Measurement of oxygen permeability of contact lenses based on analysis of porosity
Written by Malwina Lewandowska, Wanda Jasińska-Kwaśnik, Agnieszka Jóźwik, Damian Siedlecki
Published: 26 January 2015
Abstract: Oxygen permeability seems to be the most important parameter characterize the contact lens. Lenses, which permeable more oxygen to the cornea are safer, reduce the risk of infection and provide greater comfort of wearing. Oxygen permeability of contact lenses might be calculated by analysis of porosity of its surface. With using special program the size and number of pores on definite area was calculated and dependence of permeability and hydration on porosity were established.
Keywords: Oxygen permeability, contact lens, porosity