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The article deals with the evaluation the state of 120 mm mortar projectile stabilizer. It assesses a crashed projectile, whose stabilizer got stuck in the barrel during the shot. The evaluation includes the analysis of the mechanical properties, especially hardness, besides the evaluation of cracks, structure and chemical composition of the materials used. Cracks are documented with Olympus GX 51 optical microscope and Tescan Vega TS 5135 electron microscope. The chemical composition was assessed by EDS method on the Noran System Six/300 device. The hardness values of the stabilizers were obtained by LECO LV800AT hardness tester, the microhardness measurement used LECO LM247AT equipment. Material properties and microstructure evaluation was compared with the documents available in the metallurgical laboratory of the Department of Mechanical Engineering.

To describe the machining process and information of mechanical parts in petroleum engineering, the paper defines MBD machining process model from the perspective of process parts; analyzes evolutionary law of geometric features information in the course of part machining process and creates the concept of procedure machining cell; makes clear description about machining process based on procedure machining cell sequence to achieve the expression of machining process information; analyzes geometric features of procedure machining cell, proposes extended AAG based on AAG by combing with examples and links with attribute information table to complete the modeling of geometric and non-geometric features information about procedure machining cell. The research made in this paper provides a basic framework for integration of process information in 3D CAPP system.

Nowadays, there is an effort to increase the economic effectiveness, including manual work, from the aspect of the modernization of production technologies. The brazing operation is one of the operations requiring skills and experience and therefore, the paper deals with modern brazing technology of aluminium alloy semi-products which are heated only in the electric furnaces. Application of heat can lead to the formation of the perfect join of semi-products based on such materials as A 3004 and AA 4045. A thin layer called Clad is deposited on one component of the AA 4045 material while the mentioned thin layer is molten to the prescribed temperature in the furnace but the most important fact is that there is not occurrence of melting in relation to the base material. After cooling, Clad creates a perfect metallurgical join between the joined surfaces. The resulting microstructure corresponds to silumin alloy. The transition between silumin alloy and aluminium matrixes of the component is continuous and without any defects in the form of discontinuities or pores and this fact was confirmed by the evaluation of the microstructure. This technology is used in the production of battery coolers in electric hybrid cars. Tightness of brazed join is controlled by pressure and helium tests. Analysed cooler was suitable from the aspect of the performed testing procedures.

Grinding is currently still an important method for surface finishing. At FPTM JEPU is realized the research, which deals with this issue. There are carried out experiments with grinding various materials under different conditions and then are evaluated the selected components of the surface integrity, which are generally roughness Ra, Rz and Rz, material ratio curve (Abbott Firestone curve) and also obtained roundness. This article deals with grinding nickel alloy Inconel 718, when selected cutting grinding conditions were used and subsequently the surface roughnesses Ra, Rz and Rt, the surface profile and the material ratio curve were measured and evaluated.

The article deals with numerical simulation of induction heating process as a coupling of electromagnetism and heat transfer with the scope to surface temperature optimization. The article presents how the position of the inductors used in the induction heating process influence the resulting temperature of heated surface. The scope of the article is to show methodology to optimize surface temperature by numerical approach.

Lead is traditionally used for completing free-machining materials. This paper deals with newly developed lead free copper alloys. Unfortunately, lead affects the haematological and nervous system. Therefore, materials containing lead represent one of the greatest environmental problems in world production. Research Material Institute in Panenske Brezany (CZ) developed new environmentally friendly cooper alloys. Machinability of these materials was tested at the Department of Machining, Process Planning and Metrology CTU in Prague. Some of the research results related to the machinability from the viewpoint of chip forms, surface roughness, cutting temperature, cutting time in drilling with constant feed force, and forces in cutting are presented.

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 article deals with influence of chemical etching and polishing on some roughness parameters of titanium parts surface, designed for implantation into human organism. Titanium alloy Ti-6Al-4V was used for the experiment. Analysed samples were created by conventional mechanical machining methods as milling, grinding and polishing. Influence on surface and quantity of removed material by acid solution was analysed. Three methods of sample surface finishing were used, each resulting in variety of surface quality, and then two methods of chemical polishing, differed by reaction time of acid with samples surface. The samples surface was analysed optically, using stereo-microscope and evaluated roughness parameters as arithmetic average roughness Ra, ten-point mean roughness Rz, profile skewness Rsk and kurtosis Rku were measured. The modification of these parameters after the reaction was measured and analysed.

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 results of an experimental study on influence of cerium addition on structural characteristics of 42CrMo4 steel are presented. Alloying with cerium was carried out using profile filled with powdered mixture of mischmetal. The samples were taken from two ingots cast in the VHM's steelworks with standard time of casting of about 14 minutes. Three steel bars from one of the produced ingots were prepared by forging. Chemical composition, macro- and microstructure, X-ray EDX chemical microanalysis, hardness of the all steel samples were obtained. Cerium addition resulted in the formation of micrometer size inclusions which can be utilized for controlling the grain size structure of steel castings. The majority of the particles have settled at the bottom part of the casting, indicating that the convection flow during solidification was very weak. The cerium addition slightly diminished hardness of the steel. A segregation phenomenon causing inhomogeneous distribution of cerium over entire volume of as-cast samples after relatively rapid crystallization process of the steel was revealed.

Nowadays, one of the motive trend in engineering industry is transportation and manipulating technology. The hydrostatic mechanisms belong to the most important components and are created by hydraulic engines, pumps, switchgears etc. Inseparable part of hydraulic engine is a servo-valve which coordinates the fluid flow by a microscopic movement of piston. The servo-valve is a casting, usually made of ductile cast-iron that is necessary to machine. The functionality of hydrostatic circuits is influenced significantly by the precise movement of pistons.Therefore it is necessary to provide the dimension accuracy, machining quality and also the geometric shape of holes. This article describes the issue of holes reaming in hydrostatic components with a use of reamers made of sintered carbide and cermet.

Stability lobe diagram predicted by the zeroth-order approximation (ZOA) method and the semi-discretization (SD) method were compared. The methods yielded similar predictions for high radial immersions under the specified cutting parameters and the cutting tool modal properties. As radial immersion was decreased, the disagreement between the predictions of the two methods grew. For very low radial immersions, the predicted lobe diagram differed considerably. The most prominent difference was an additional set of lobes corresponding to the new type of instability, the period doubling bifurcation which was predicted only by the SD method. Numerical simulation verification of the stability boundaries confirmed that the predictions of the SD were more accurate than those of the ZOA method.

An automotive industry belongs among the most important industrial branches in the Czech Republic as well as in the Europe. An adhesive bonding technology is a method of connecting which is used in many industrial branches nowadays. It also plays its irreplaceable part in area of a construction of automobile bodies. The adhesive bonding is the method which is easily implemented among requirements of a serial production. A strength and a reliability of adhesive bonded parts of automobile bodies and other traffic means are key. That is why adhesives used for the adhesive bonding in the automotive industry are characterized by their increased strength and resistance (e.g. adhesives Betamate). The paper describes the cohesive and strength characteristics of these adhesives. It focuses on a tensile strength, a hardness and a shear strength depending on a thickness of used sheets of metal when an increased thickness of the sheet of metal decreases its plastic deformation and so it decreases a liability of the adhesive bond to peeling.

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.

Not only engineering production at present is characterized by increasing an international competition. It is achieved higher productivity with simultaneous improvement of quality parameters of machined parts by using of process fluids. In other words, the use of process fluids positively improves and increases the both the qualitative as well as quantitative parameters of the technological processes. Process liquids in machining occupy an important place and influence the outcome of the all processes. Choosing a suitable process fluid should be carefully considered. It is well known that, different machining technologies have different cutting conditions and thus completely different requirements on process fluids. Selection of a suitable process fluid is more important that the management of manufacturing companies admits. Unfortunately, the selection of suitable process fluids is very often underestimated.

The solution of the aerodynamic task is a very complex issue. An accurate description of the aerodynamic field is used for the specification and the solution of an aero-acoustic task. With the numerical modelling onset the possibilities of investigation of the flow around body are still expanding. The aim is to establish basic parameters by which the flow field around the body is described. This paper deals with the numerical modelling of the flow around a cylinder and a sphere and with the evaluation of the parameters (coefficients) for these bodies. The modelling is performed using the software tools Ansys Fluent and OpenFOAM. The basic setting of the numerical simulation is described and test of the calculation stability and mesh quality for a given task is done. The calculation setup is briefly shown for the computational tool OpenFOAM. At the same time, the experimental result is shown in this paper to verify the results of the numerical simulations. The experimental equipment - a wind tunnel is specified by its basic parameters and possibilities for the aerodynamic task measuring. Experimental data are obtained using by hot-wire anemometry - one-wire and two-wire probe.

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.

This paper deals with evaluation of ground surface of Ti6Al4V alloy according to surface roughness. This titanium alloy has large scale of utilization, it is used for implants and surgical instruments. Significant problem during grinding of titanium alloys is generation of large amount of heat which can cause surface cracks, increase hardness of surface and increase of tool wear. Each specimen was ground on surface grinding machine by diferent cutting conditions. The roughness parameters Ra, Rq, Rz and Rt were measured five times on each specimen in each axis (axis y - direction of feed rate, axis x - perpendicular to the feed rate). The values of the roughness parameters (Ra, Rq, Rt and Rz) are presentated in the graphs where we can see the influence of the cutting conditions on these roughness parameters.

Pressure die casting of metals is a method of precise metal casting, where molten liquid metal is forced under high pressure into a mould cavity. Requirements of engineering and automotive industries for perfect castings with smooth surfaces, exact dimensions and thin walls determine the nature and direction of development of pressure die casting of metal. This article analyses the possible causes of a foundry defect - short run - generated during casting based on varying technological parameters.

The contribution contains results of bonded joints strength tests. The tests were carried out according to the modified standard CSN EN 1465 (66 8510). For bonding the spruce three-ply wood of 4 mm thickness was used (according to CSN EN 636). The test samples of 100 x 25 mm size were cut out from a semi-product of 2440 x 1220 mm size in the direction of its longer side (angle 0°), in the oblique direction (angle 45°) and in the direction of its shorter side (crosswise - angle 90°). The bonding was carried out using eight different domestic as well as foreign adhesives according to the technology prescribed by the producer. All used adhesives were designated for wood bonding. At the bonding the consumption of the adhesive was determined. After curing the bonded assemblies were loaded using a universal tensile-strength testing machine up to the rupture. The rupture force and the rupture type were registered. Finally the technical-economical evaluation of the experiments was carried out.

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.

The paper dealt with tool-wear, tool-life and chip creation regarding the cutting speed for machining by conventional and coated tools. The cutting speed is influenced by several parameters. The determination of optimal cutting speed is challenging question. Situation is more complicated in case of coated tools. The important is criterion of optimization. Moreover, the presence of the coating changes chip creation process and stress state during cutting. The paper provides complete experimental T-vc dependencies obtained in turning regarding various parameters as depth of cut, feed for different machined and cutting tool materials. Paper describes also different tool-wear mechanisms of uncoated and coated tools. Finally, the paper analyzes stress state in tool as simplified model of contact of tool rake and chip for conventional and coated tools involving different mechanical properties of coating and substrate material, temperature and different thicknesses of coatings.

In aluminum strip production, profile formed in hot rolling is critical to flatness control in the subsequent cold rolling, and selective work roll cooling is marked by the flexible control of complex high-order shape defects. Therefore, a setup system of selective cooling is developed to achieve the whole cross-section profile control in hot rolling. It includes a real-time work roll thermal model based on finite deference method and a strip profile predictive model based on RBF network. A spray pattern is obtained using an iteration method, as the "basic pattern" for the setup, for the situation when roll thermal contour need to be maintained. Based on the predicted profile error, adjustment of the basic pattern is made by fuzzy inference to get the final setup spray pattern, under which the profile error can be reduced during the threading.

The microstructure, the phase constitution and the tempering charts of Cr-V ledeburitic steel Vanadis 6 subjected to sub-zero treatment with various soaking times in liquid nitrogen have been investigated. The microstructures have been characterized using the light microscopy, scanning electron microscopy and X-ray diffraction. The hardness has been evaluated by Vickers method. The matrix is martensitic with certain amount of retained austenite, irrespectively to the time of sub-zero treatment. The amount of retained austenite, however, decreases up to the soaking time of 17 h and then remains almost constant. The microstructure of sub-zero treated steel contains enhanced portion of small globular carbides, as compared to conventionally heat treated material. These particles have a size of around 100 nm in most cases. The as-quenched hardness manifests a moderate increase due to the sub-zero treatment. The hardness decreases during subsequent tempering and this decrease is more pronounced in sub-zero treated samples.

The article describes main possible usage of results of dynamic loading simulation with using of computational simulating system MSC. ADAMS. AVT and simulating computational model of track vehicle undercarriage. Main contens of article is the descripton of using of results for design value make-up file of changes of vehicle chassis parts and its new operating settings. The second described possibility of results simulation calculations usage is making - up of aproximate relations for transaction of fast orientation calculations. The next possibility of usage of simulation results is the possibility to verificate of mathematic model. The optimalization of influence changes of several design value together is last mentioned possibility of usage of simulation calculations results in the contens of this article.

The article is aimed to the development of homogenization procedures for fibers reinforced composite materials. The development of these procedures during the homogenization was performed by using a representative volume element (RVE). Two RVE versions were developed, hexagonal and square fiber arrangement. Both modules are automated and have been developed in the Python programming language with connection to FEM software Abaqus, which serves as a solver, and post processor. Afterwards the assembled modules follow homogenization of particular composite structures, which results are in a comparison with result gained from other homogenization methods (analytical methods for homogenization of composite materials) are processed into tables.

A unique combination of properties makes aluminium one of the most versatile engineering and construction materials. The aluminium alloys can be machined easily and economically if suitable practice and proper tools are used. A statistical design of experiments was performed to investigate the effect of selected cutting parameters and a cutting fluid on the surface roughness of AlMgSi1 aluminium alloy (EN AW 6082) machined by end milling. For the experimental procedure, three cemented carbide end milling cutters of diameter 12 mm with 3 cutting edges were used. The input parameters taken into consideration were helix angle, cutting speed, and using a cutting fluid. With application of ANOVA, the helix angle was investigated as the most significant parameter. The other ones were not statistically significant. To eliminate the negative impact of the cutting fluid on the health and environment, dry machining is recommended in this research.

Thesis is interested in accurately detect moisture inside of plaster moulds, that will be measured by microwaves apparatus. Part of the thesis is also construction and assembly of the stable apparatus, so that it is possible to monitor the effects of microwaves on a plaster sample, then evaluate the moisture content of the sample and compare it with the weight test. The actual moisture measurement will be performed in several ways, such as by measuring the reflection or attenuation of electromagnetic waves. The result of this thesis will be a graphical representation of moisture to measurable variables relationships, gained from the microwave apparatus.
Plaster moulds are quite known, but casting technology requires from plaster moulds not only dimensional accuracy after drying, but as well surface smoothness, resistance to cracking upon drying and sufficient strength and breathability, or minimal gas evolution during casting. The presence of water during the casting process is not very welcome phenomenon. It is therefore very important to set correctly dry form, otherwise it may happen that the moulds can be during casting destroyed, or cast alloy can create a casting bubble by the influence of moisture in the form. That means discarding of the products.

Fe3Al iron aluminides with Zr addition appear like promising materials for high-temperature applications. Carbon is often present in alloyed iron aluminides because of its occurrence in raw iron. Therefore Zr addition can lead to the formation of zirconium carbides in the structure of the alloys. Also other carbides can form depending on carbon amount. The size and distribution of carbide particles can affect high-temperature behavior of aluminides. Thermal expansion of alloys with 0.25, 0.5 and 1 at.% Zr was studied by means of coefficient thermal expansion (CTE) measurement. The structure of alloys was obtained by scanning electron microscopy. Energy dispersive analysis and X-ray diffraction were used for phase identification.

Ball-section raceway groove and narrow groove ring (BGNGR) is a complex part of bearing rings. The mandrel for the forming of the narrow groove will push and press the metal and lead to instability of the rolling process. Therefore, the effect of the narrow groove on the metal flow is investigated. Two methods for BGNGR rolling are presented, and by deducing the dimensional relationship between rectangular blank and deformed ring, the finite element models for both methods are established and simulated in Forge3D software. Method I is proved to be a failure through the finite element analyses of the effect of the narrow groove on the metal flow. Based on the analysis result in Method I, the Method II with appropriate mandrel profile for the going up metal is proposed. The simulated result shows that the BGNGR whose geometry size meets the requirement can be rolled by Method II.