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This paper deals with standard test method for the measurement of vibration-damping properties of materials, ductile cast iron - graphitic cast iron with the spherical shape of graphite. Investigation is focused on its mechanical properties, chemical composition and microstructure, which are necessary as input parameters for computational modeling and numerical analysis. The vibration or oscillating of experimental samples is closely connected with such parameters as natural shapes (eigenshapes) and natural frequencies (eigenfrequencies). Preparation of a geometric model of a homogeneous beam sample and numerical analysis was performed by finite element method in the ADINA software environment. This paper can be used for further development and growth from the aspect of application of computational tools in the area of damping and eigenfrequency properties for construction materials. This paper deal was supported by the Slovak Grant Agency KEGA 007TnUAD-4/2017, VEGA grant No. 1/0649/17, VEGA grant No. 1/0589/17 and resulted from the project “Center for quality testing and diagnostics of materials”, ITMS code 26210120046 relating to the Operational Program Research and Development funded from European Fund of Regional Development

The paper deals with the choice of a method and methodology of planning the technological processes to ensure the required quality of the surface layer of parts, resting on the principle of utility proposed by authors, which is an overall indicator of efficient use of external and internal impacts upon operational characteristics of products with modified surface layers: 1) the modification of properties without allowance removal, with a change in surface layer characteristics; 2) the removal of the allowance portion until reaching the material layer, having the desired operational characteristics; 3) the coating of products with surface layers, made from materials with desired characteristics and having a structure in which the operational properties are obtained by imparting the preset characteristics (wear resistance, heat resistance, etc.) to parts (including those made from other materials), applying the useful properties of coatings deposited; 4) the deposition of coatings comprising the inclusions of conductive and dielectric materials (e.g. ceramics, abrasives, etc.). The paper discovers the ways of using the principle of utility to justify the effectiveness and the scope of preferred application of technological processes of surface layer modification. It presents the methods of automation in selecting the technical means for enhancing the operational properties of high-tech products.

The mathematical model and numerical simulation results of metals alloy solidification process based on the finite element method (FEM) are presented in this paper. After completion of the mould filling process the main solidified of molten metal takes place and its shrinkage. The phenomenon of casting shrinkage cannot be avoided. However, it is possible to minimize the occurrence of its negative effects on the casting quality. The phenomenon of shrinkage defects formation was included in the numerical calculations and they were tried to reduce them. It is important aspect of this work which makes possible the prediction of the location of the casting defect depending on shape of the riser. The results of computer calculations of the solidification process of the three-dimensional casting together with the conical or cylindrical riser are discussed in detail and presented.

The aim of the current paper is to determine the influence of material thickness on the quality aspects of AWJ processing of the AL6061T651 alloy. The analysis is performed under different working conditions. The parameters taken into account to quantify the quality of processing are those defined in the ISO/WD/TC 44 N 1770 standard: width of the processed surface at the jet inlet (Li), width of the processed surface at the jet outlet (Lo), deviation from perpendicularity (u), inclination angle (α) and roughness (Ra). The obtained results emphasise a significant influence of material thickness on both, the surface quality and process productivity.

Turning tools come in different shapes and sizes, geometry, base material and coating, according to their destination. They are widely used both for obtaining parts and for machinability tests. In this paper a short review about high-speed steel (HSS) turning tools and their coatings is presented. Hard coatings formed on the tool material should be functional depending on the tool final application. Requirements for hard coatings and technological problems for layer formation on the real cutting tool are discussed.

This paper presents micro-bulges investigation on laser modified tool steel. The aim of this study is to understand the effect of laser irradiance and interaction time on surface morphology configuration. An Nd:YAG laser system with TEM00 pulse processing mode was used to modify the samples. Metallographic study shows samples were analyzed for focal position effect on melted pool size, angle of peaks geometry and laser modified layer depth. Surface morphology were analyzed for surface roughness. Laser modified layer shows depth ranged between 42.22 and 420.12 μm. Angle of peak bulge was found to be increase with increasing peak power. The maximum roughness, Ra, achieved in modified H13 was 21.10 μm. These findings are significant to enhance surface properties of laser modified steel and cast iron for dies and high wear resistance applications.

Feasible product geometries manufactured with micro-hydroforming, as well as process stability are crucially influenced by the microstructure of the used tube material. The higher ratio of grain size to tube wall thickness d k / t 0 in micro-hydroforming, compared to conventional tube hydroforming, leads to an increase of scattering of process parameters and instabilities. This paper presents experimental and theoretical results for the micro-hydroforming of tubes made from stainless steel and from platinum with a focus on the correlations between the microstructure of the workpiece material, the stress state during forming and the resulting stability of the forming process. Investigated tube dimensions were 800 µm outer diameter and 40 µm wall thickness of the steel tubes, respectively 1650 µm and 76 µm of the platinum tubes. The average ratio d k / t 0 was about 0.3 for the steel material and about 0.9 for the platinum alloy. It has been shown that superimposed axial stresses are suitable to reduce the restricting influence of an increased ratio d k / t 0 and to improve the forming result as well as the process stability.

Since the main purpose of asymmetrical rolling is to impose high shear strains on the sheet, in order to obtain ultrafine grain structure, the friction between the rolls and the sheet has to be kept relatively high. This means that asymmetric rolling is performed with dry rolls. The paper presents a numerical analysis of the roll wear during asymmetric cold rolling of 5083 aluminum alloy. The finite element simulation was used to calculate the amount of roll wear by Usui’s equation. FEM simulations were carried out with using software DEFORM 2D. The influence of the friction coefficient on the roll wear and the material flow was discussed. The sliding velocity, interface pressure and temperature were used to calculate the roll wear. The results of simulation can be used to optimize the asymmetric rolling process to improve surface quality of aluminum sheets.