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This article builds on existing results of testing hardened steel bearing ring machining. Grinding technology is preferably used for this area as a standard. Turning with cubic boron nitride has been used as an alternative machining technology. Results indicate that in mass production the values accuracy of degree IT 4 can be achieved. Arithmetic mean deviation of the profile is then in the range of Ra = 0.2 - 0.4 μm. During testing several kinds of cubic boron nitride material were used. The material that showed best results was chosen for further experiments. Subsequently it was tested under different cutting conditions on two types of machine tools. It was tested cutting in smaller range of depth of cut and wider feed values. The resultig feedrate and cutting depth which correspond to best result of arithmetic mean deviation of the profile Ra were selected from those tests. Subsequently, the testing was carried out at various cutting speeds and particularly at two different sizes of tool overhangs.

Texture of the surface is very important in process reproduction of the components. Not only in engineering area, but also in other industrial sectors, the assessment of the surface texture ranks among basic techniques of the determining the surface properties of the component. Pretreatment of the surface can reduce running costs in the case of coating on the tools. The paper describes the changes of the surface textures of the HS6-5-2-5 steel CSN EN ISO 4957 with different technological treatments of the substrates, coating and subsequently polishing of the coating. Substrate was sandblasted (wet) and polished before coating. Coating nACo® was applied by PVD method and surface of the coating specimens was subsequently polished by μLap method. Surface textures together with properties of the coating are decisive factors for their lifetime and durability of the cutting tools. The qualitative assessment of the changes surface texture was carried out by the 3D topography measurement of the surface by using Talysurf CCI Lite. TalyMap software was used for evaluation of the changes surface texture. For evaluation of the surface were used parameters: Sa - arithmetic mean deviation of the surface [μm], Sdq - root mean square slope of the surface [-] and Rk - core roughness depth [μm]. The results in the paper demonstrate positive effect of the polishing on texture coating on the tools.

The Al-10Si-21Fe and Al-20Si-16Fe (wt.%) alloys were prepared by short-term mechanical alloying and subsequently compacted by spark plasma sintering. Prepared samples were characterized by ultrafine-grained microstructure with average dimensions of each structural component that does not exceed 200 nm. This resulted in excellent mechancial properties e.q. hardness and compressive strength. Hardness of both prepared alloys reached almost 400 HV5 and remained the same value even after 100 hour of long-term annealing at 400 °C. The Al-10Si-21Fe alloy reached ultra-high compressive strength of 1033 MPa. The casting Al-12Si-1Cu-1Mg-1Ni alloy, generally considered as thermally stable, was used as a reference material. Even the reference materail was thermally treated by the T6 regime, it exhibitted lower mechanical properties compared to the investigated alloys event at laboratory temperature. During annealing, the reference alloy significantly softened reducing its initial compressive yield strength and compressive strength from 430 MPa and 680 MPa to 180 and 498 MPa, respectively. Additionally, hardness reduction by 50 % to the resulting 63 HV5 was observed. Compared to this results, the investigated alloys maintained theirs high initial hardness and compressive strength suggesting excellent thermal stability.

The industrial use of aluminium alloys has significantly increased in the last decades. Most machined parts are produced by cutting. Therefore, research in this field is quite important nowadays. Surface roughness is an extremely important quality parameter of a product, such as geometrical sizes and their tolerance. The authors in this article analysed the machinability of die-cast aluminium alloys with silicon often used in the industry. The turning experiments were made with different diamond tools edge geometry. The surface roughness obtained during turning was analysed in detail. Phenomenological models were created with which the surface roughness producing ability of the examined tools can be estimated in technological design.

The process of the aluminum alloy casting was investigated. Two materials of the mold were used to observe the effect of thermal conductivity on the time of the solidification. The simulation of the process was conducted in the CFD software respecting the radiation. The results of the designed model of the casting process were compared with the analytical solution obtained from literature.

Pherrography uses microscopic methods for the detection of morphological characteristics of wear particles deposited on pherrogram. The result of pherrographical analysis is to create the pherrographic track on pherrogram and then to assign the type and intensity of wear. The position of nonferrous metals on the pherrogram is quite clearly defined. Assessment of particle size, particle shape and distinguishing kinds of material are the result of observation. Nonferrous particles are also divided according to the color. Metal particles can, under certain circumstances, have different colors as a result of excessive oxidation of the particle surface. The article deals with the identification of nonferrous particles on pherrographical track of motor oil. This assessment is carried out in relation to the mode of wear of oil and machine. Part of the experiments is also microchemical analysis for subsequent analysis of certain hard identifiable metals.

The aim of this research work was to determine the causes of the cracking unit rolled at initial hot rolling of the AlMg5 alloy. Failure occurs in the central area of rolled plate. In the alloy was carried out chemical composition of the material in the near the defect and its comparison with the chemical composition of the entire melt, which pointed to a significant reduction of the magnesium content of the area defect. Macroscopic, microscopic and fractography analysis were carried out both in the area of the fracture surface and in the immediate vicinity. The analysis indicated that the fracture surface, and also the structure in the area of the fracture surface show a character oxide inclusions and oxide films or spinel inclusions. The following EDS analysis were carried out on a scanning electron microscope to confirm the presence of oxide inclusions of spinel-type character Al2MgO4 on the fracture surface of the rolled material. It could be stated that when casting a gradual burning out of magnesium in casting furnace and thus to reducing it's some 0.5 - 1.0% and the formation of spinel inclusions. Spinel inclusions then initiated cracking during hot rolling.

Iron aluminides belong to a group of intermetallic materials. Atoms of intermetallics are long-distance arranged that's why these alloys show some interesting properties as high temperature strength or corrosion resistance. Besides of beneficial properties iron aluminides have some disadvantages as e.g. brittleness at room temperature or a sharp drop in strength above 600 °C. It has been shown that the high temperature mechanical properties can be enhanced through third element addition.
The structure of Fe3Al alloy with addition of niobium was studied in two states - as cast state and in state after stabilization annealing at 1000 °C for 50 hours. Phase composition was investigated for these samples, because it can affect the alloy properties. The phase composition was determined using scanning electron microscopy (SEM) equipped by energy dispersive analysis (EDX) and electron backscattered diffraction detector (EBSD). The influence of heat-treatment on coefficient of thermal expansion (CTE) was also studied. The CTE's were measured by means of horizontal dilatometer.

The article deals with mechanical properties of plasma nitrided steel. Experimental work was focused on evaluation of influence of plasma nitriding process to notch toughness of steel, the experimental were realised on V-notch samples of size 10x10x55 mm (according to CSN ISO 148-1 standard). Nitrided layers were applied to steel 30CrMoV9 which were subsequently evaluated by metallographic, GDOES and microhardness method. The notch toughness tests of steel were carried out using the instrumental Charpy hammer at temperatures -40 °C, +21 °C and + 70 °C. The results of experiments showed that plasma nitriding process has a direct impact on change of notch toughness parameters. The notch toughness of plasma nitrided steel was significantly decreased. The measurements thereinafter showed that values of notch toughness at low temperature (-40 °C) decreased but also at higher temperature (+70 °C). It was found a dependence of notch toughness values of plasma nitrided steel between the testing temperature and plasma nitriding process parameters.

This article deals with mechanical and chemical properties of nitrided layers which were created by plasma nitriding technology. The aim is to achieve an enhanced surface hardness, better wear resistance, reduced friction coefficient, increase fatigue limit or corrosion resistance. Experiments are focused on using of plasma nitriding process for surface treatment of cavities with diameter of 6 mm. Nitrided layers were applied to steel PO 209 which were subsequently evaluated by metallographic, GDOES, XRD microanalysis and microhardness methods. The results of measurement showed trends of chemical composition of alloying elements after chemical-heat treated process in cavity. Plasma nitriding process is applied for increasing of surface hardness of material in deep cavities. Mechanical properties of tested material were significantly increased. Surface hardness and microhardness is depended on content of nitride formed alloying elements in material.

Experiments and numerical simulations were conducted to analyze the deformation zone of aluminum cable in the conform extrusion process, and complex metal flow is observed by finite element. In this report, detailed studies were especially focused on the width of the extruding dies mouth and leakage gap which influenced on the metal deformation, then the stress and strain distribution and contact force distribution of arbitrary step were obtained with respect to different technical parameters among random steps. Furthermore, the relationship between the parameters of Δh and W/H was given, indicating that the intense internal Shear Band-IISB and leak gap affect the metal forming behavior, and enlarge obviously plastic deformation zone in a certain range. Consequently, it's proper to be helpful for metal homogeneous deformation to reduce the entrance width of the extruding mold.

An important aspect of rail vehicle dynamic analysis is a ride comfort analysis and a prediction when passengers and cargo can experience adverse conditions. The computational software utilisation helps to determine forces and accelerations in various positions through the body of the rail vehicle in order to predict ride properties or evaluate ideas for ride comfort in advance. This paper is aimed to the dynamic simulation of the rail vehicle running on a real track. The rail vehicle model creation, computations performance and determination of accelerations badly needed for the ride comfort evaluation is performed by SIMPACK package. Parameters of passenger rail vehicle model correspond to the four-axle two-bogie BR481 rail vehicle. The track model on that the vehicle has been run corresponds to the real track section in Slovakia.

Paper is focused to analysis of emerging sediment-casting furnace for the casting alloys of Al - Si. The aim in the analysis of of sediment is to confirm or disprove that a substantial portion of sediment are formed due to segregation of particles the wire used for refinement structure of alloys. Subsequently, on the basis of chemical analyzes of the various structural components of the sediment to determine the nature and methylene chanizmus formation of sediment. The optimal delay time at a temperature of alloying when master alloys type of AlTi5B1 is 5-10 minutes. All these master alloys act almost immediately, and in most cases, their effect is not dependent on time, temperature holding time of alloying, only at some alloys (e.g. AlSi11, AlSi9Cu3) after exceeding 30 minutes of holding time smoothing effect worsening slightly. The optimal temperature of alloying coincides with the temperatures that are used in technical practice in the casting of Al-Si alloys. After exceeding this temperature (about 750 C°) represents a slight coarsening of the structure. This is caused a slight deterioration of softening effect due to formation of clusters of particles of TiB2 or leads to their segregation, which reduces the possibilities of creating of active crystallization nucleuses.

This paper presents the analysis of heat load on the atmosphere by flue gases emitted from boilers combusting fuel wood with moisture content W = 10 - 60 %. From the analysis results, that the heat load on the atmosphere is affected by the moisture content of combusted wood, as well as the construction of the heat generator's boiler part - the extent of cooling of exhaust gases. The value of heat load factor on the atmosphere by flue gases from combustion of dry fuel wood with moisture content W = 10% at flue gases temperature ts = 120 0C is FQ = 96,22 MJ.GJ-1. The factor's value at moisture content of the fuel wood W = 60% and flue gases temperature ts = 200 0C equals FQ = 340,67 MJ.GJ-1.

Aim of this paper is to explain capability of ANSYS to model induction heating of inner rolling bearing ring. This physical problem requires simulation of the interaction of three physical fields. First field is harmonic low-frequency electromagnetic, second transient thermal and third static structural analysis. The skin effect requires the fine mesh in areas near boundary of modeled ring in the vicinity of inductor. MFS concept is used to couple these three physical fields. Main result of this analysis is the thermal field history in inner ring. This analysis is used to obtain sensitivity data for appropriate shape and size of inductor to austenitize required domains of inner ring.

Productivity growth in the machining industry is associated with a reduction in the cost of cleaning and recycling contaminated process fluids. The proper use of process fluids or lubricants can bring a significant reduction in friction and the amount of wear, thereby leading to a reduction in power consumption. The use of nanolubricants in modern technologies is a major advancement. Nanolubricant is a new system composed of nanometer-sized particles dispersed in a base lubricant. The use of nanoadditives in the form of nanoparticles is highly efficient due to their high chemical and biological activity. The doping of lubricants with nanoparticles is one of the ways to solve problems with the removal of bacteria, whereby improving the biological, chemical and technological stability of process fluids. In the article, we monitor the effects of doping process fluids with nanoparticles of silica (SiO2) and titanium dioxide (TiO2) on the friction coefficient of friction pairs of Si3N4 balls against steel 16MnCr5, EN 10084-94 and Si3N4 balls against aluminium AlCu4BiPb balls.

The Al-brasses are considered corrosion resistant technical materials especially used in pipe systems in energy industry. They are mostly exposed to flowing liquids environments where they are loading chemically and mechanically and their lifetime in practice condition quite vary. The aim of our research work is to compare corrosion and mechanical properties of four Al-brasses from various producers. The Al-brasses have very similar chemical composition but differ in microstructure, surface state what affect their corrosion and mechanical behavior. By chosen experimental methods and analyses the effect of the mentioned parameters are investigated.

Manufactures of automotive engines and complete vehicles strive for the lowest possible fuel consumption, which also leads to the use of motor oils with lower viscosity. Lower viscosity of oil reduces internal friction and provides faster distribution of oil into lubrication points, but simultaneously reduces the size of transmitted power. The design of automotive engines use plain bearings, which are based on aluminium, brass. Further are used steels with coating based on aluminium and bronze. The paper describes the impact of viscosity of motor oil to wear of basic materials, which are used in production of plain bearing. Reichert tester M2 for evaluation the lubricity from Petrotest Company was used in order to assess ability of motor oils to create proper lubricating film. Reichert tester M2 belongs to a group of equipments simulating real frictional contact. Stabinger viscometer was also used for the precise determination of viscosity of various types of motor oils.

The paper addresses the integration of the inertial navigation unit implemented into the system of controlling the robot. It analyses dynamic properties of the sensors of the inertial unit, e.g. gyroscopes and accelerometers. The implementation of the original system of controlling the robot on the basis of autonomous navigation systems into the production system is a dominant part of the paper.

The aim of this study is to investigate the creep resistance of molybdenum disilicide (MoSi2-SiC) based composites with different types of embedded particles. The materials were prepared via powder metallurgy using high temperature controlled reaction sintering (CRS). The creep experiments were performed in uniaxial compression at constant stress in the temperature range from 1273 K (1000 °C) to 1473 K (1200 °C) for applied stress from 50 to 100 MPa. Creep was tested by stepwise loading: in each step, the load was changed to a new value after steady state creep rate had been established. The applied stress dependences of the creep rate at different temperatures were analyzed in terms of stress exponent (n) and activation energy (Q). Possible rate-controlling mechanisms were suggested.

In modern analysis of structures it is not only important to study structures subjected to static loading but also to study the effects of dynamic loading. One of the results of impact loading is the dynamic response of structures. This can cause far more damage than the effects of static loading. Composite materials are more and more used in engineering praxis. This allows the creation materials of high strength at low weight which are more durable then the same construction made of homogenous materials. This paper presents a study of dynamic response of carbon fiber reinforced polymer composite plates in the form of modal analysis and transient response (subjected to unit pulse point load in the center of the plate). The plate consists of layered uniaxial carbon fiber fabric and the layers are layered symmetrically at different angles for various variants. The response in the form of displacement magnitude is measured. At the end a comparison study is presented for each analysis.

The article deals with experimental measurements of force effects that direct blow develops taekwondo sportsman. Power effects are captured using a high speed camera. Experimental measurements have confirmed the results of many scientific papers that deal with the measurement of the force effects of combat sports athletes, etc. There are described some methods that are used in medicine and biomechanics to view internal organs or injury detection.

At the present time, consumables assortment intended for utilization of MIG brazing process enables its application possibilities also for the joining of high-alloyed austenitic steels. In that case, the substitution of arc welding processes (such as MIG/MAG, or TIG) by the brazing process makes it possible to limit the weldability issue related to the crystallization of weld metal (hot cracking) and to the deformations (induced by excessive amount of heat input to the joint). Additional technological benefits may be offered by an application of flux-cored wires, which have been utilizing successfully within arc welding processes.
Submitted paper is aimed to verify differences in the character and behaviour of arc metal transfer and in the stability of arc during MIG brazing of austenitic stainless steel by selected types of solid and flux-cored wire electrodes.

Thanks to their chemical and mechanical properties, the process fluids (PFs) can significantly affect the process of machining [2], [15], [16], [18]. It is particularly important that PFs should positively influence the quality of the machined surfaces of machine parts and durability of cutting tools [4], [5], [6], [7], [10], [11], [12], [14]. Other significant factors in PFs are economic and environmental [17]. The costs of the acquisition, use and disposal of PFs must not be too high. As part of the research project in collaboration with the company Paramo, a.s. and the Technical University of Liberec, completely new environment-friendly PFs (labeled as PF01, PF02, PF03, PF04, and PF05) have been developed and evaluated. In the Laboratory of Machining at the Technical University of Liberec, the effects of these new PFs were examined from a viewpoint of a number of technological aspects. This article presents the results of experiments conducted on structural steel 16MnCr5 and stainless steel X2CrNiMo18-14-3 face milling using these newly developed eco-PFs.

The paper experimentally and theoretically analyses the velocity profile of air in laboratory stand pipework. Flow velocities measured using a hot-wire anemometer and a vane anemometer were compared with the results of numerical simulation. The k-ε turbulence model was used in the numerical solution of flow rates and for determining the velocity profile using the ANSYS_CFX program. Using power law, this profile was described via an analytical function. Velocities determined by measuring with both instruments in the investigated place in the pipework showed lower values in comparison with the numerical solution. The cause of the difference in velocities was probably inaccurate stating of the volume flow of air through the ultrasonic anemometer. Measurements and simulation showed slight asymmetry in velocity which is related to an insufficiently large volume of the equalisation chamber and the mutual position of the input and output openings.

The article is the possibility of energy saving of glass furnaces Bonacci when operating. A proposal to energy saving is aimed at changing of the control process of furnaces and installation of closing doors inlet and outlet ports of furnaces. By inlet and outlet ports of these continuous furnaces considerably leaks thermal energy when are not used (i.e. breaks at work). The doors are designed as a hollow panel, which is filled by isolation. This leads to a considerable saving of energy and to reduce of operating costs. The current control process of furnaces is now obsolete and can not flexibly changed it according a change of manufacturing products. The newly designed controlling systems is controls not only the kinematics, i.e. moving actuator of glass, but also temperatures in furnaces and newly inlet and outlet doors for closing of holes.

Liquefied technical gases are used in almost all sectors, regardless of whether this is industrial application (engineering, food processing, electronics), as well as in health and other sectors. These gases are kept in cryogenic vessels. A cryogenic vessel is a two-walled vessel where the inner vessel is used to keep the gas, the outer vessel is used as packaging, and the space between the inner and outer vessels is thermally insulated. The insulation must have such parameters to ensure that the stored cryogenic gases remain in the liquefied state for the longest possible time. Various materials and methods are used to insulate the vessels, but the most common insulation for cryogenic vessels is perlite insulation in combination with vacuum. The problems of isolation of cryogenic vessels using perlite are dealt with by only a few specialized companies that produce vessels for liquefied technical (cryogenic) gases.

Magnesium materials seem perspective for application in the field of biodegradable implants. Such materials are gradually degraded, without the formation of toxic products in the organism. Different approaches have been performed to improve mechanical properties and corrosion resistance of magnesium based materials. Among them, preparation of composite materials with magnesium matrix and inorganic reinforcement is very attractive. Hydroxyapatite (HA) is considered as suitable reinforcement because it is included in human bones. Presence of HA in composite can support the process of osseointegration. The resulting properties of Mg-HA composites are affected by the amount and particle size of the HA as well as the actual process for the preparation of the composite. This paper deals with the preparation of composite materials of Mg-HA with different contents of HA reinforcement by suitable combination of powder metallurgy method (milling, pressing, extrusion and spark plasma sintering). The effect of these methods on final structure and mechanical properties was observed. All prepared composite materials were characterized by uniform distribution of reinforcement particles in the structure and slightly different mechanical properties based on HA content and preparation method.

The paper deals with the hardness of pressure die castings in dependence on the method of their subsequent processing. As a crucial influence there was taken cooling rate of parts after their removal from the pressure die mould. Moreover there was monitored influence of the machining allowance and the thermal treatment. Measurement of hardness was done on die castings from alloy AlSi9Cu3(Fe) by methods acc. to Brinell and acc. to Rockwell. Regarding reality that properties of die castings are influenced also by filling method, for the experiment there was chosen part casted by so-called central ingate where exists presumption for the uniform filling and thus also uniform distribution of casting properties. The measurement took place for 2 months after casting, machining and eventually after thermal treatment of parts. On the basic of measured hardness values by methods acc. to Brinell and Rockwell there was determined the converting coefficient between these values.

Foundry aluminum alloys have many advantages compared to foundry alloys of different metals, such as great castability, low melting point, narrow crystallization period, good chemical stability and hydrogen content, which is the only gas soluble in aluminum, which can be minimized by applying of appropriate technological conditions. Provision of the quality of aluminum production is based on an adequate purity of used materials. That is the reason why liquid aluminum, after electrolysis or after remelting secondary aluminum, requires treatment prior to casting. Cleaning and treatment of aluminum melt are particularly important tasks in contemporary fields of use, for example elaborately shaped products, foils etc. The only gas soluble in aluminum is hydrogen, whereas other gases are inert or create insoluble compounds when in contact with melted metal. That is the reason why it is necessary to know the whole dissolution process of hydrogen in aluminum melt as well as ways of its removal. One of those ways is system I-60 SIR.