No. 4

Author: Igor BARÉNYI

Abstract: The paper deals with some aspect of nitriding and nitrocarburizing of two middle alloyed high strength steels. Theoretical part very briefly describes fundamentals and benefits of mentioned chemical-heat treatments. Experimental part is focused on hardness profile measurement and depth layer evaluation along with microstructure study of basic areas of layer. Results from experimental part of the paper allow to increase utility properties of castings.

Keywords: high strength, microhardness, nitridizing, nitrocarburizing, layer, microstructure

Vol. 9, 2015, No. 4, p. 1-5

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Author: Igor BARÉNYI, Jozef MAJERÍK

Abstract: The paper deals with some aspects of welding and machining of HARDOX 500 abrasive resistant steel. These technologies are most widely used for processing of the Hardox semiproduct to final component. Part focused on welding assesses the weldability of the steel and decreasing of mechanical properties in HAZ including simulation of processes responsible for degradation. Part targeted on HARDOX 500 machining described condition and requirements on machine tools and its inserts. Experimental test of hard rough face milling with two different types of carbide inserts and acquired technological parameters are also mentioned.

Keywords: Hardox, hard machining, tool wear, tool life

Vol. 9, 2015, No. 4, p. 6-9

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Author: Ján BEZECNÝ, Igor BARÉNYI, Mária LIČKOVÁ

Abstract: Nowadays, promptness and operative delivery of preliminary but objective results of component failure during its exploitation are needed. For complex material analyses are required to perform several material tests as are chemical composition determination, test of mechanical properties, micropurity and microstructure evaluation, RTG phase analysis, fractography analysis and other. These tests are too expensive in costs and spent time. Application of needed corrective arrangements and restoration of continual production depend on quick and in-time delivery of test results to the producer or user. Application of reflection electron microscope (REM) in evaluation of fracture plane for the real case of damaged component after few load cycles is described in the paper including advantages and disadvantages of REM. Fractography analysis was used to determine of the surface carbonization at standard quenching and tempering. This was consequently confirmed by optic metalography. Main advantage of REM is minimal requirements for test sample surface preparation what are cutting to the dimensions and cleaning. Only disadvantage of this method are qualification requirements and experiences of operator.

Keywords: damage, REM, carburizing layer, intergranular fracture

Vol. 9, 2015, No. 4, p. 10-14

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Author: Erika HUJOVÁ, Vladimír ÁČ

Abstract: The paper deals with possibilities of texture analysis of metal alloys using X-ray diffraction. The basic principles of the methodology, experimental equipments and procedures are shown. There are described a measuring methods of pole patterns and orientation distribution function of texture and interpretation of the results for practical use. Finally, we will show some of the results of measurements on α-brass CuZn30.

Keywords: X-ray diffraction, polycrystalline materials, pole figures, ODF – orientation distribution function, texture analysis, α-brass CuZn30

Vol. 9, 2015, No. 4, p. 15-23

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Author: Alexej CHOVANEC, Alena BREZNICKÁ

Abstract: In a submitted paper we are going to deal with possibilities in using statistical instruments and methods of product quality management and with application of simulation modeling in production and maintenance introducing procedures on examples being solved in mechanical engineering companies. Sustaining competitiveness and increasing a level of provided services requires permanent innovative changes to be made by organizations. Innovation management in mechanical engineering and production takes the commissioning of new processes for granted into organization operation, into quality of products or services in area of organization and processes management, implementation of new /improved/ technologies, innovation of new, improved products and services.

Keywords: statistical instruments, manufacturing process, simulation experiments, machines equipment.

Vol. 9, 2015, No. 4, p. 24-31

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Author: Milan JUS

Abstract: This paper presents a photovoltaic renewable energy source system focused on the use of photovoltaics in Slovakia and at near abroad. The experimental section contains measurements, where there is a tendency to choose the best solar panels for orientation in a southerly direction, and performance differences were found in uniaxial and biaxial performance monitoring panels.

Keywords: renewable energy, photovoltaic, photovoltaic cells, photovoltaic panels, photovoltaic technology

Vol. 9, 2015, No. 4, p. 32-38

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Author: Ľubomír UHERÍK

Abstract: Presented is a complex mathematical model biomechanical interaction human - hand weapon. With this model it is possible to carry out calculations for two typical shooting positions - shooting standing and kneeling shooting. The calculations are made for shooting with ammunition calibre 5.56 mm. For this type of ammunition is provided a recoil force which acts as the external loading of the virtual model of a man. Mathematical model of biomechanical systems man - Hand Gun permit a deflection weapon during firing and misalignment caused when shooting bursts.

Keywords: Hand weapon, human, interaction, model, biomechanical

Vol. 9, 2015, No. 4, p. 39-47

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Author: Jozef DRGA, Jozef CHOVANEC, Stanislav ŠIMKOVIČ, Jozef KÚDELČÍK

Abstract: We present the investigation of Magnetite using density functional theory in this contribution, the properties of Fe3O4, which makes it usable for a material for nanoparticles in magnetic fluid, will be discussed. The Fermi Energy and Density of States were calculated.

Keywords: magnetic fluids, nanoparticles, magnetite, density of states

Vol. 9, 2015, No. 4, p. 48-50

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