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Roller bearings are a very important part of modern machineries and equipments. They have a significant impact on the smooth running, reliable performance and durability. Replacing worn or damaged roller bearings often require extensive disassembly of the machine and the costs often exceed the price of the replaced bearings. There is an influence of the correct bearing construction and dimensional accuracy on the durability, but the grade and quality of used steel and its heat treatment are very important, too. Tempering is an important chapter. Tempering has the effect to modifying the properties of martensite after quenching and transformation of residual austenite, which is related to the change of bearing rings dimensions, growth, roundness and hardness. Decrease in hardness of bearing steel is associated with a reduction in the basic dynamic load rating of rolling bearings and thus durability. In this article there is analysed the influence of quenching and tempering on their mechanical properties after heat treatment. There was also used simulation software to verify the possibility of modeling of bearing rings quenching.

Homogenization is defined as a method of heat treatment, which consists of holding time at high temperature near the liquidus (approx. 0.7 to 0.8 the melting temperature) to eliminate chemical inhomogeneity diffusion processes. Cause of segregation is selective crystal solidification in the gradual change in composition of the solid phase. Melt began to appear after certain of the hypothermia during cooling, and the growth of germs in accordance with the general laws of crystallization. Each rigid layer has a different chemical composition. The first part of the solid phase ingredient low concentration of the element last, on the contrary, very high. Susceptibility to crystal alloy segregation is greater, the greater the temperature interval solidification of alloys and the horizontal distance between the liquidus and solidus lines. Crystal segregation will also increase with increasing content of alloying elements, which in these experimental alloys occurs as containing 6-9% alloying elements. Crystal segregation can be removed by diffusion, for which it is necessary to create conditions by homogenization annealing.

The paper deals with the methodology and suitability of mathematical models applying analysis of the signal-to-noise (S/N) ratio as well as analysis of variance (ANOVA) and surface response methodology (RSM) on effect of TiAlN coating on chip ratio when drilling with HSS Co5 twist drill with diameter of 8 mm. Experimental work was performed according to design of experiment (DoE) Taguchi method. Cutting speed vc (m/min) and feed f (mm/rev) were selected as control factors in three levels and chip ratio K was used as a response variable. The main aim of this study is to establish relevant methodology for short term testing and find adequate mathematical model for chip ratio parameter K = f(vc, f) as a function of cutting condition when drilling with PVD coated and uncoated tool. Statistical software Minitab 14 was employed to process and evaluate of experimental data. The effect of feed and cutting speed on chip ratio was investigated through analysis of the signal-to-noise (S/N) ratio and analysis of variance. Equations for chip ratio K as a function of control factors were developed.

Aluminium alloys prepared by rapid solidification (RS) are characterized by very fine microstructure, increased hardness and thermal stability, which determine these alloys to be used especially in an automotive or aerospace industry. However, there is no practical use for rapidly solidified alloys in the form of thin ribbons and further processing of the material is necessary. Compacting of rapidly solidified alloys can be realized by hot extrusion or hot pressing. The aim of this work was to prepare a metallic powder from RS alloys by cryogenic milling and to compact the powder into a bulk material by hot pressing. Both microstructure and phase composition of hot pressed products were studied and compared. Alloys of chemical composition Al-Fe-X, where X means transition metal Cr or Ni, were studied.

Magnesium alloys belong to materials, which are nowadays more and more often used for various technical applications. Their principal advantage consists in their low specific mass and high specific strength, while their drawbacks consist, among other, namely in low mechanical properties at higher temperatures. Obtaining of fine grained structure can be achieved by high cooling effect of the mould. This can be ensured by use of metallic mould, especially in combination for example with die casting, or with low-pressure casting or gravity casting. Some other casting procedures exist, however, such as casting into expendable moulds, the cooling effect of which is substantially weaker. In these cases it is necessary to achieve the fine grained structure in another way. In this case an important role can be played by inoculation of material, i.e. addition of suitable nuclei. This paper deals with the influence of the inoculation on microstructure and thermo-mechanical properties of castings based on selected magnesium alloys.

This paper deals with investigation of surface damage induced by grinding operation as a result of dry grinding through micromagnetic technique based on Barkhausen noise. This study presents information about wet and dry grinding and associated surface integrity expressed in such term as residual stresses, structure alterations beneath the ground surface and corresponding magnetoelastic responses. Lack of coolant or insufficient coolant supply can be found as a reason of surface burn during grinding. Therefore, this paper compare magnetoeslatic responses of surface obtained during wet and dry grinding. Results of experiment indicate that properly suggested monitoring system can reliably detect surface burn induced by thermal overload of ground surface.

Surface roughness is assessed on the basis of various criteria either qualitative or quantitative. The principle of qualitative methods is a subjective comparison of machined surface with the model (the standards) of the surface. The standard board is used, which corresponds to the type of surface technology, the type of an instrument, i.e. the way in which the surface was created. Its accuracy is not sufficient. Methods for expressing roughness numerically based on the defined parameters of roughness are classified as qualitative. Contact or non-contact measurement equipment is used here. Cutting material by abrasive water jet (AWJM) is one of the non-convention production technologies. The AWJ as "tool" leaves visible waviness on the machined surface. It is largely determined by the choice of the abrasive water jet feeding speed. Most of the research work qualifies the state of surface after AWJM according to roughness parameters depending on the cutting parameters. According to this knowledge the surface roughness varies linearly with increasing the cut depth. If we take feed speed as one of the quality assessment of the cutting AWJ parameters, we can watch its influence on changes the relief, (topography) of the cutting area.

The fragment of investigations of primary crystallization process of casting made from chromium cast steel and chromium cast iron contain about 17% chromium was described in the article. The analysis of change in temperature gradient on cross-section of cooling model casting was introduced. To the investigations was applied TGDA (thermal gradient and derivative analysis) method worked out in the Department of Foundry in Silesian University of Technology in Gliwice which consists in multi-drop measurement of cooling temperature in casting using thermocouple locate on the direction of transferring warm from the casting to mould. On the basis of registered cooling curves were worked out graphs of temperature gradient and its first derivative (curves TGDA). The changes of course of TGDA curves describe the kinetics of primary crystallization process on cross-section of the studied casting and provides of created primary structure. At the analysis of temperature gradient curves also was used TDA (thermal and derivative analysis) method.

The components with formed surfaces are being an important category of the machine parts. They are applied in the most of industrial branches. In order to produce such type of machine parts it is necessary to harmonise the contradictory requirements, e.g. the minimal production time, the required precision of dimensions and the surface quality. A relevant role is playing the chosen machining strategy specified for the above-mentioned demands, namely during the finishing operations. The most important evaluation criteria for selection of the concrete CAM-system are: the disposable machining strategies, visualisation level of the proposed process and recognition of the virtually machined surface. The term "machining strategy" represents the pre-defined (and in the CAM-system also the available) tool trajectories that are optimised for machining of the variable formed surfaces so that the work-piece could be machined most effectively. A projection and evaluation of the cutting trajectories is not a simple process. There are at disposal many professional articles, which started to be published after occurrence of the first software solutions created as a support of the NC-software development. A development of the new strategies, i.e. the projection and optimisation of the new methods for control of the tool movement on the machined surface, is a multidisciplinary area, which requires knowledge from the theory of machining, descriptive geometry, informatics and also mathematics. The standard machining applications are such strategies, for example, that are able to optimise the cutting conditions in order to achieve a constant loading of the tool and in this way they enable prolongation of the tool durability as well as improving of the manufactured surface quality. Another important area is also evaluation and comparison of the existing strategies because the proper choice of them can help to reduce the machining times and the tool wear-out due to a shortened length of the tool operational path. This fact has a relevant impact on the production efficiency. The main topic of this paper is a description of the quality analysis focused on a surface area, which was machined by means of the various milling strategies and at the same time there were monitored deviations of the machined surface in comparison to the original 3D-model of the free-form surface area. This matters is analysed in [1], [2], [3], [4].

Recycled aluminium alloys are made out of aluminium scrap (new or old) and workable aluminium garbage by recycling. Due to the increasing production of recycled aluminium cast alloys is necessary to ensure their strict metallurgical control. The mechanical properties and the microstructure character depends on the chemical composition; melt treatment conditions, solidification rate, casting process and the applied thermal treatment. The mechanical properties depend on the morphologies, type and distribution of Si, Cu, Mg and Fe-phases, on the grain size, DAS and porosity distribution. Improvement of mechanical properties and structure of Al-alloys can often significantly increase the using lifetime of a casting. Different elements are added to achieve the optimum casting and mechanical properties. Modification can be achieved by several methods as faster solidification, mould vibration, melt agitation in mushy state and melt inoculation by using chosen elements like Sr, Na, Sb etc. Present work is focused on study of the effect of Sr-modification on the structure and mechanical properties of recycled AlSi10Mg cast alloy. For study and identification of intermetallic phases' was utilized standard (HF), colour (MA) and deep etching (HCl) in order to reveal the three-dimensional morphology of the silicon particles and intermetallic phases. For element composition of the specimen was used X-ray (EDX) analysis. Finally, the effect of modification on silicon morphology and fracture surface was examined.

This paper evaluates the influence of different amounts of antimony addition on the corrosion resistance of the alloy Al-Si. The corrosion of aluminium alloys, methods of testing and evaluation of corrosion and the influence of antimony in alloying of Al-Si alloys is described in the introduction of the paper. The alloy Al-Si specifically AlSi7Mg0.3 alloyed by 0; 0.001; 0.005; 0.01 and 0.05 wt. % of antimony was chosen for the experiment. The prepared alloys were subjected to the two types of corrosion tests in the environment - atmosphere and corrosion chamber. The corrosion attack of experimental samples was evaluated from both the macroscopic and the microscopic point of view. The aim of this paper is to assess the influence of antimony on the corrosion resistance of the alloy AlSi7Mg0.3 which was alloyed with different amount of antimony and compared to the alloy without alloying.

This paper deals with surface roughness and surface profile in high precision methods of materials finishing. One of them is ELID grinding process and the second method is fine grinding. There is surface profile and roughness compared of the three materials samples - carbide steel and two aluminium alloys. In the paper are shown the principle of the ELID grinding and fine grinding, results of surface measurement between ELID and ground surface. Both methods are very precision in the focus on surface roughness - measured units in nano scale. The paper shows also real topology of the surfaces and visible tool marks especially by the fine grinding method. Next we can see new possibilities in finishing methods for different areas of the production, automotive, aerospace, medicine and cosmic industry.

The control of DC servomotors used in robotics is usually carried out using conventional PI controllers that might serve their purpose well in case of absence of any parameter variation. Nevertheless, this is rarely case in practice as with any change in load the inertia moment is naturally changed resulting in much worse performance of a PI controller. The main topic of this paper is the comparison of two possible control methodologies for decreasing the parameter variation sensitivity of the whole control system : acceleration loop and fuzzy controller. It is shown that even a basic fuzzy controller with rather small number of fuzzy rules (computationally undemanding) performs very well even under conditions of extreme inertia moment variation and is capable of outperforming a conventional method of using acceleration loop.

This article provides perspective into creation of virtual 3D models of manufacturing devices and optimization of existing machine tools by using an alternative scanning device and freeware software applications (open source elements). This alternative offers scans of components surfaces that are from the viewpoint of precision and quality comparable with much more expensive devices. Various parts of the paper describe the process of creation of the environment with the use of Kinect scanner device and various software tools. At the end an additional options are provided for using with sensing device.

Composites are materials which combine properties of two and more phases and create entirely new material. In case of the polymeric particle composites one phase - a matrix is represented by the polymeric material most often in a form of an epoxy resin and the second phase - a filler is composed of inorganic particles. The paper deals with the polymeric particle composites whose matrix is composed of the epoxy and polyester resin with a high concentration of a waste corundum (Al2O3) particles. The paper focuses on chosen mechanical qualities of these materials: an abrasive wear resistance and an impact strength. Increased portion of the filler in the matrix predetermines these systems to considerable abrasive wear resistance. This hypothesis was confirmed by carried out experiments when the volume loss decrease of the composite systems with the matrix saturated with the particle filler reached values 0.04 cm3 whereas the volume decrease loss of the epoxy resin without the filler reached 0.56 cm3. The maximum applied saturation of the matrix with the particle filler was reached at the polyester resin when this value corresponded to 50 volume percentages.

The aim of the work was carried out research on the causes cracking formed aluminum work pieces in the assortment of rods, which sometimes occur in the mechanical machining (turning, drilling) for alloys of Al-Cu. A typical representative for the machining of aluminum alloys is AlCu4MgMnPb alloy, most of which performs heat treatment for hardening increases the ultimate strength. For the given alloy were carried out qualitative and quantitative fractographic analysis of fracture surfaces after machining in order to determine possible causes cracking of the material and thus his insufficient strength. This paper clearly documented that the fractographic analysis methods can clearly and in the extent required to provide answers to the causes of insufficient strength of the material when cutting. At the same time points out the possible causes of cracks in this alloy in machining and ways for their elimination.

Introduction into problems - The aim of the paper was microscopically analyze protective layer by coated sheets after corrosion loading which were pre-treated by various ways. The samples were divided into 4 groups according to the pretreatment type and duration of corrosion load. After a corrosive effect on the corrosion chamber the protective layer was subjected to microscopic evaluation. For samples of group I and IV have to degrade the protective layer and the formation of corrosion products on the base material which causes degradation of the protective layer and shorten its life. For samples of group II and III microstructural analysis showed good condition of the painted surface layer and the base material showed no presence of corrosion products. It again confirms the need for compliance of technological conditions for the pretreatment of the surface particularly in the application of modern less aggressive means.

An investigation was carried out through a study of the influence of material anisotropy and geometrical parameters of the cylindrical plastic parts reinforced by short fibres, on the state of stress. It has been shown that the result of such injection-moulded processes is an anisotropic product, whose mechanical behaviour differs considerably for that of classical types of isotropic solids. Unlike unreinforced plastics, fibre composites exhibit different stress phenomena and mechanical properties notably in cases where composite parts are highly curved. These unusual effects of their mechanical properties thus need to be considered carefully in the course of designing of reinforced plastic parts.

This contribution deals with the need of continual experimental study of the phenomenon that relates to the increasing demands to the quality of engineering production and also to the productivity and economy of the production. Experimental part is focused to the influence of the tool coatings, which significantly affect the roughness of the material machined with the use of the cutting plates made of high-speed cutting steel. The plates were used in the series of the experiments, what allows us to create the models of real situations in the area of concrete manufacturing technology and subsequently to analyze them. To the measured and evaluated parameters belonged: the roughness of the machined material after the use of coated and uncoated tools. Planing technology is realized until there are major visible changes in cross roughness of the machined material, what means the increasing of Rz values. This is caused by the fact, that the coating was removed from the cutting edge, what is considered as the blunting of the tool. Measured values are statistically expressed in the form of the graphs.

The article presents problems with commercial inverter source Rapid Arc application on fillet and V-grooved welds. Principal and conditions of the process are explained and especially restriction due to source and feeder upper power limit is described. Case study of "weld design for fabrication" method was demonstrated, where type of weld and shape of groove is designed on the base of experimental results of process penetration behavior at 1/2 V-groove joint. Results are described and discussed, using special welding parameters monitoring equipment and software. A change of metal transfer behavior was recorded in accordance with torch angle setting and originally explained.

This chapter investigates the establishing process of virtual tool that in its logical core utilizes an approach based on the open source philosophy exploited for the work with the environment of augmented reality and its application in assembling processes. The traditional possibilities of how the engineer can use tools of augmented reality in form of normal commercial devices to collect the information about position of observed object in the working environment concern special devices with general structure formed by elements of motion tracking systems or technology of visual markers. In the beginning, the chapter briefly focuses on general problems in the application processes of virtual components and logical scripts in the area of the augmented reality. In following phase it provides fundamental philosophy and logical steps of new presented application of the augmented reality whereupon some samples can be provided created by means of logical operations and virtual elements from the open source environment. In the final step of this article chapter is clarified application process for creation and development of virtual software and hardware elements that are necessary for work in the augmented reality environment.

Design of a Casting Die made of aluminium alloy components using CATIA software is described in the article. Computer aided design and construction is necessary for the creation of each part. A lot of tools are implemented in the CATIA program. These tools are used to design cast parts easily. A few aspects are necessary for this technology. To achieve a quality fine-grained structure without porosity and the oxide inclusions, a possibility to observe the casting, solidification, tempering, easy creation of core and cavity, possibility of rapid design whole mould. This factors influence efficiency of construction, quality of the product and production economy. Use of CAx technologies is necessary to meet the requirements [7]. Simulation in some simulating program occurred before this construction. These programs work on basis of Navier-Stokes law and law of conservation of momentum [4]. Combination of these products influences efficiency, productivity and financial expenses.

The Austempered Ductile Iron (ADI) and Austempered Grey Iron (AGI) represent the most progressive group of grafitic irons with reference to mechanical properties. These properties depend on accurate observance of default structure, chemical composition and isothermal hardening conditions. ADI/AGI castings are mostly used in automotive industry for moving parts and safety critical items. The production of ADI/AGI in the Czech Republic is insufficient, even if the automotive is the important member of our industrial production. The NDT can be used as the tool of 100% inspection - that provides constant production quality and could support the production of this promising material. This work deals with the development of inspection procedures based on the magnetic and ultrasonic structuroscopy.

This article deals with grinding of the hardened and tempered steel in different coolants. The G-ratio is one of the important parameters of grinding process and shows efficiency of this. The development of machining technologies is still moving forward, there are new materials and types of tool using in production and manufacturing. With a new materials usage we want better parameters of process, e. g. higher G-ratio, lower heat balance and better surface quality after machining. New types of abrasive grains that we used are based on Al2O3 - microcrystalline corundum and parameter of G-ratio and surface quality after grinding will be described in this article. For experiment were chosen three types of coolants and one of grinding wheel. We can see changes of G-ratio and surface quality during grinding at different coolants.

In the development of new cutting materials as well as the application of recent ones it is necessary to know the dependence of their durability on cutting speed. Cutting speed, which determines maximum tool durability, can be derived from it. Recent methodology of finding out this dependence is based mainly on long-term machining examinations and tests, which are demanding on time and material and they can be realised only in laboratory conditions. The paper presents a suggestion of short-term, but equally precise examination, which is based on the observation of tool wear depending on cutting speed.

This paper reports on the outcomes of an investigation concerned with the machining performance of thermally treated recycled glass in the vibratory mass finishing process. The surface finish generated with the glass is compared to that achieved using conventional polyester bonded media under different lubrication conditions. To help understand the wear behavior of the glass, measurements of the surface topography were obtained at intervals throughout the tool life, using a replication method. A further series of tests were undertaken to establish self-attrition rates. It has been demonstrated that the machining performance of recycled glass media is comparable to that of conventional media in respect of surface finish (Ra), brightness cycle time, self-attrition rate and tool life. This innovative work provides strong promise for the introduction of this new media into the abrasives marketplace for polishing, superpolishing and superfinishing of engineering materials.

Precision machining and especially hard machining is a topic of high interest at present. Surface integrity requirements increase. Hard precision machining may substitute some abrasive operations. There are some advantages of hard cutting over the abrasive machining. Abrasive machining has traditionally performed the finishing process of hardened steel. But, the availability of hard and super hard cutting tools enable the machine tools to reach surface quality of hard machining like to those obtained in grinding processes. A surface is not only a geometric entity but also a layer with its own structure and properties. These properties are affected by many factors, e. g. by cutting temperatures, friction, deformations in the primary deformation zone and the surface layer of the transient (machined) surface, by cutting tool geometry, work hardening, cutting environment, etc.

The alloyed iron aluminides with Fe3Al matrix are used as structural materials. Nb, Zr, Ta additives in combination with carbon appear like promising for high-temperature applications [1, 2]. The carbon addition leads to the formation of carbides (NbC, ZrC, TaC) in the structure of the alloy [2, 3]. The presence of this phase in an appropriate shape could enhance high-temperature mechanical properties of aluminides. The effect of the Nb and C addition and the effect of the heat treatment on the phase composition of this alloy were studied [4, 5]. The alloys investigated in this work were annealed at 1000°C/1h and 1150°C/1h in the air. The phase composition was studied by light optical microscopy (LOM) and scanning electron microscopy (SEM) with energy dispersive analysis (EDX).

The research focuses on verification of FEM simulation of GMAW bead on plate welding with experimental results. In the program Visual Environment simple FEM simulation of GMAW bead on plate welding on Al alloy EN AW 7022 was created and these simulation data were compared with measured experimental data. To create good FEM model setting of heat source and material parameters are of great importance. To set parameters of heat source measurement of welding parameters, metallographic sample, weld bead and end crater was experimentally done. During experiment, temperature was measured by several thermocouples and measured temperature was compared with simulation data. The difference of measured and simulated data was at maximum only 10°C and we can conclude that this result is very good. Simulations that obtain results close to reality are very useful for designing welded constructions. Designing from using precipitation hardenable Al alloys, e.g. series 7xxx, materials prone to softening, when welded, can be thus made easier and safer using simulation software.

This paper reports on the outcomes of a study concerned with the mechanical properties of a new abrasive tool manufactured wholly from thermally treated recycled glass. These properties will aid in understanding the behaviour and performance of the treated glass. Mechanical properties were investigated using the most current and advanced nano-indentation methods. A computer controlled Nano Indentation hardness test (NHT) machine was used to obtain values of hardness and elastic modulus. The nano-indentation process was equipped as a FEM parametric model. The model was then processed by purposely developed numerical objective optimization algorithms in order to determine comprehensive material properties. The aim was to establish the optimal solution with reference to mean square root optimization criterion. The results show large elastic recovery upon unloading similar to a pure silica reference material and a surface roughness unique to this material which is entirely crystalline. The indentation mapping shows significant effect of heat treatment cycles on mechanical properties of recycled glass media.