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Mechanical alloying is one of the ways how to prepare nanostructured and amorphous metallic materials. In this paper we used this method to prepare Mg-Zn alloy containing 50 wt.% of zinc. Powders produced by milling in a planetary ball mill were consequently compacted by the SPS method, a very fast method which prevents grain coarsening. The prepared samples were subjected to a closer examination - microstructure, phase composition, hardness and short-term thermal stability were studied. We found out that the prepared powder consisted of Mg and Mg7Zn3 phases, which were very fine and homogeneously distributed. After the SPS compacting, the metastable Mg7Zn3 phase decomposed and new phases (Mg, MgZn, MgZn2, Mg2Zn11) formed. The compacted sample possessed relatively inhomogeneous microstructure and hardness about 260 HV5. Investigation of the short-term thermal stability was accomplished by annealing at temperatures up to 300 °C. We observed changes in hardness - it regularly decreased up to 200 °C and then it slightly increased.

This article deals with the non-destructive ultrasonic testing of split sleeve butt joints by ultrasonic methods. Split sleeve is used to repair gas pipelines with gas leakage. The new ultrasonic methods TOFD and Phased Arrays are compared considering to the selected butt weld configuration. To compare testing methods, ES Beam Tool software was used to prediction of ultrasonic beam spread through weld joint. TOFD technology was selected to butt weld section testing according to the beam spread simulation results. The results of ultrasonic testing by TOFD method were compared with results of macrostructural analysis of weld joint. Controlling the suitability of testing method to planar defect identification, the artificial defects were prepared and tested. The appropriate setting of measuring technique can be predicted from experimental results.

This paper deals with influence of tool wear on surface integrity after hard turning expressed mainly through the Barkhausen noise responses. Grinding operations can be sometimes replaced by hard machining (hard turning and milling). Chip separation in hard turning differs from mechanism of chip separation during grinding. For this reason surface integrity expressed in variable terms differs. Surface integrity can be expressed in such term as surface roughness, shape deviations as well as characteristics such as residual stresses, structure transformations, and microhardness alteration. Being so, it can be beneficial to apply the suitable nondestructive surface testing techniques to obtain information about surface integrity expressed in complexity of this term. Nowadays, Barkhausen noise technique is widely used in a variety of industrial applications. This technique is sensitive to stress state as well as microstructure features. For this reason, Barkhausen noise emission is used in this study to reveal magnetic and stress anisotropy developed in a certain stage of tool wear. The paper also discusses very high BN responses associated with the specific aspects of produced surfaces.

Polyurethanes belong to a wide group of polymers which are applied in many industrial branches. Some polyurethanes can be filled with various types of fillers which optimize their properties for given application. In the paper there are described basic mechanical properties of a constructional two-component polyurethane resin which was filled with microparticles of a glass powder. The aim of the experiment is to define a resulted hardness, a tensile strength and a shear strength of the filled polyurethane resin and set its utility properties further to an application usage of a company PSP Izoterm Ltd. From the measured values 14% increase of the hardness of the filled systems compared with the unfilled resin is visible, the shear strength of the filled systems did not differ statistically significantly from the unfilled polyurethane, the tensile strength of the polyurethane filled with 5% of the glass powder was statistically the same with the strength of the unfilled polyurethane.

The paper deals with a squeeze casting process. This process added a new knowledge in to research in the branch by crystallization of aluminium alloys. Due to this purpose there was designed a special tool, which was placed on hydraulic press. The squeeze casting was carried out on an aluminium alloy (AlSi12, with 12 % silicon). The main aim was study of the aluminium alloy structure, which was established at a pressure of crystallizing melt. In this way of the material crystallization was produced a truncated cone part with the larger the base (∅ 100 mm x 105 mm). The structure of specimens was monitored on a light microscope and was evaluated by means of software NIS Elements. The main results of the pressure melt to fine crystalline structure, which is represented fine dendrites both on surface and in an interior parts of the processed material. The influence of this pressure on the mechanical properties was monitored too.

In this paper the effect of factors entering into the optimisation of cutting conditions and affecting production costs in turning is analysed. Optimisation of cutting conditions affects every manufacturing company in the field of machining, and represents an important area of the economy these enterprises. The aim of the research was to determine the size of the influence of input factors on the results of the calculation of the optimisation of cutting conditions using inserts in turning. Each constant is moving at a definite recommended range of values depending on various conditions. If we find out what the most important input factors most affecting the calculation of the optimisation of cutting conditions, we are able to focus primarily on the following factors. Influences of selected factors on costs are presented in graphs showing their interdependence. The influences of the input factors received from overall analysis were categorized by importance and created a list containing three groups significance of individual factors. According to the created groups a company can more easily focus on the parameters that most affecting the cost of turning, thereby improving the selection of specific technical, economic or time values in the company.

The structural content of castings and non-conformities that might occur in pressure die casting is mainly connected with technological parameters. Analysis of the casting structure helps identify a group of causes of non-conformities which are connected with improper choice of technological parameters. The non-conformities identified in the pressure die castings discussed in the paper were analysed by means of metallographic examinations. A electron scanning microscope was used in the study for the analysis of the structure of casts. This analysis allowed for identification of the causes of e.g. shrinkage depressions or misruns. The analysis of the structure of a casting in the location of the depression revealed insufficient cooling time used for this casting.

MicroScan 600-1 is a digital Barkhausen noise analyzer. It is designed for fast nondestructive surface quality control and subsurface layers of machine parts from ferromagnetic materials and for evaluating of defects which are caused by changes of residual stresses. By the instrument based on an analysis of the Barkhausen noise is determined the value of magnetoelastic parameter. Experiments which evaluated the influence of different types of process fluids to the machining process and technological properties of the machined parts from constructional steel 16MnCr (ČSN 14 220) were carried out in the laboratory of the Department of Machining and Assembly at TU in Liberec. Turned, milled and grinded test samples by using five different types of process fluids were evaluated using the analyzer. For The comparison was machining carried out also without inlet process fluid, i.e. "dry" and with the process fluid - water. Measurements of magnetoelastic parameter were performed repeatedly and measured values were statistically processed. The paper presents the resulting values of this parameter showing the influence of process fluids on the properties of the surface layer of the machined parts.

Al-Si alloys are leading casting alloys based on aluminum. Machining of aluminum alloys is currently frequently used and it is an important area of production. The paper deals with an experiment that was conducted at the Faculty of Production Technology and Management, University of Jan Evangelista Purkyně in Ústí nad Labem, where was machined alloy AlSi7Mg0,3. Samples were made for processing from the master alloy AlSi7Mg0,3, subsequently unmodified and modified of strontium Sr. This paper describes the evaluation of tool wear in terms of how or strontium modification may affect (reduce) the tool wear.

With development of a number of branches (automobile industry) the demand of increasingly more complex and more exacting castings that are mechanically cleanable with difficulties only is growing. Application of the technology of disposable water soluble cores from inorganic salts is one of solutions of troublesome problems of removing the cores from places hardly accessible for cleaning. Solubility in water enables reversal crystallization of the salt from the water solution what is a precondition for forming a closed ecological cycle of the core manufacture. Application of salt cores can be met in processes of low-pressure casting, gravity casting in dies, and in connection with just running research project in pressure castings from Al-alloys. The article brings results of checking the cores made from cooking salts (NaCl) predominantly available on the Czech market. It is aimed at two main technologies (shooting and high-pressure squeezing) of their manufacture and it investigates the influence of chemical composition, form and morphology of the grain surface on mechanical properties (bending strength) of water soluble salt cores for their application for high-pressure die casting of Al-alloys.

The paper deals with modelling and optimization of dynamic characteristics of a semiactive suspension of the working machine seat with a vibration absorber. The suspension is composed of a spring paralelly ordered with a semiactive damper controled by the sky-hook control algorithm. For the improvement of the dynamic characteritics of the semiactive suspension there is also analysed the effect of a vibration absorber. The dynamic characteritics of the suspensions are optimized by the multiobjective optimization, where besides the component respecting the effect of the effective accleration of the seat also the effect of the effective relative displacement between the seat and fhe floor of the working machine cabin is considered.

In the sphere of the metal sheet bonding namely single overlapped adhesive bonds are used. Their production costs less and they confirm strength requirements in many cases. The great part of the single overlapped adhesive bonds research was focused on a geometrical setting of adhesive bonds, an adhesive layer thickness and on mechanical properties of adherents. The analysis of the adhesive bonds strength calculations is ignored. The calculations stated according to the standards are often simplified and they do not take into the regard an adhesive bonded material and an adhesive layer thickness. The aim of the research is to define if the adhesive bond strength calculated according to the standard ČSN EN 1465 is the same as the reduced strength according to Mohr's and Guess state of stress theory regarding the adherent deformation and the adhesive layer thickness in the calculation. The issue is solved by the experimental research and statistical testing.

The articles deals with the way of calculation of tangential stresses over non-elliptical contact patch, where is possible to utilize with advantage the Kalker's simplified method FASTSIM. This method named FASTSTRIP is adapted for non-elliptical contact area calculated by means of the Strip method. This method is almost quick as FASTSIM and the results are similar to the CONTACT results. This method may be useful for rail vehicles in track dynamics computation.

Alloy modifying is common practice for improving the structure of the material. One of often used material, where the modification is used is AlSi7Mg0.3 alloy. And modification of AlSi7Mg0.3 is often realized by strontium. The paper deals with an experiment that was realized at the Faculty of Production Technology and Management of Jan Evangelista Purkyně University in Ústí nad Labem, which dealt with the effect of modifications by strontium on the structure of AlSi7Mg0.3. In frame of its experiment were analyzed metallographic samples and were observed structures of unmodified and modified material on the microscope. Was evaluated result of modification on the structure.

The aim of the research was to evaluate influence of porosity size on mechanical properties of AlSi7Mg0.3 (EN AC 42 100) alloy before and after thermal treatment. For the analyses casts of the same production type (forms used for tires production) were used. They were casted employing low-pressure casting technology. Since the negative influence of porosity on mechanical properties of Al alloys is generally known there is no quantitative assessment. In this research relation of porosity size in the structure of AlSi7Mg0.3 alloy and its mechanical properties is verified and quantified. Static tensile testing has proven the relation between porosity size in a structure of an Al material and its mechanical properties. Image analysis was applied in quantitative measurement of the porosity. The measurement was performed on prepared metallographic specimens. Porosity size is considered as a fraction of pore area to the total area of the analyzed specimen and is taken in percentage.

The paper deals with the mathematic modeling of the liquid turbulent flow in the pipe with circular cross-section. The aim is to compare two methods of solution for various geometries and Reynolds numbers. One of the methods is simulation of the system in the commercial software ANSYS Fluent, the second one is analytical solution for simple geometry by equation usually applied in the common design process. The work arises from the requirement to design the computational model based on the FVM, which enables to simulate the various physical phenomena which appear at liquid flow. The solved problem is quite range and therefore the work is only the first part of the systematic investigation. This basic part is important for the decision of the suitable software tools, turbulent model, etc. The investigation of the heat transfer on the cross flow over the tube placed in the bounded surrounding.

Technical literature presents numerous experiments with rotary turning tools application. Their advantages include extremely high durability, better quality of the machined surface as well as good chip shaping. Their wider industrial utilization was prevented due to the fact that a bearing is extremely dynamically stressed by a cutting force. Antifriction bearings have to big sizes and cause oscillation in the system, while sliding bearings manifested short durability and slackness inside. The authors of the paper tried to solve the mentioned problem by the application of an adjustable tapered roller bearing, ensuring a stable machining process. The paper contains the design as well as the results of the experimental verification obtained by the application of this improved tool.

This paper presents achieved results by measuring of force load tool by turning of nickel alloy Inconel 718 with sintered carbide with progressive chip breaker designed by Pramet Tools Ltd. Company and with cutting ceramics inserts produced by Greenleaf Company. Authors deal with studying of force load which is exposed the cutting tool by conditions, when are achieved limit values in view of tool wear. In the end it is carried out a comparison of intensity of components of cutting force for these limit conditions. Very interesting is finding that by machining with worst cutting conditions the force load on insert cutting edge is smaller than by machining with best cutting parameters. This fact can be reasoned by the fact that at higher cutting conditions we are getting into the area of HSC machining for Inconel 718 and therefore the cutting forces are smaller. There is more heat produced in cutting zone. This influence undesirably sintered carbide during cutting process. Vice versa, high temperature influences positive cutting with cutting ceramics, as show simultaneously carrying experiments.

Al-Si Alloys are a leading casting alloys based on aluminum. Machining of aluminum alloys is currently frequently used and it is an important area of production. The paper deals with an experiment, that was realized at the Faculty of Production Technology and Management, University of Jan Evangelista Purkyne in Ústí nad Labem, where was machined alloy AlSi7Mg0.3. Samples were made for machining because of the master alloys of AlSi7Mg0.3, where part of the castings was left in its original condition and part of the castings was modified by strontium. This paper describes the evaluation of surface roughness obtained after machining of these castings in terms of how the modification by strontium can affect this.

Research paper discuss the possibility of vibration detection on production machine and also presents devices and methodology for evaluation of vibration amplitude using non-contact laser interferometer and contact piezoelectric vibration sensors. Experimentally determines the influence of technological conditions on the quality of functional surfaces. Furthermore, paper evaluates the influence of technological conditions during planar grinding on the vibration amplitude of the grinding spindle and presents correlation between grinder vibration amplitude and quality of the product.

This article describes the determination of geometric, mass and stiffness parameters of the individual part of plateau wagon. After measurements were taken the position change of the chassis of the vehicle body and wheel when driving the vehicle over obstacles was observed. The obstacles were formed by wedges. Experimental detection of parameter has been used in the analytical investigation of kinematically excited system of three-body space flexibly stored and linked.

Polyurethane resins belong to a group of polymers which can be easily filled with inorganic particles. Filling of the polymeric materials, either with particles or fibres, influences resulted properties of the arisen material - composite. The particle fillers can improve a wear resistance, they can optimize tensile characteristics and reduce the polymer price. The paper describes the polyurethane resin as a material recyclation bearer of the waste inorganic particles of the corundum, the artificial garnet and the silicon carbide. The experiment results certified that the mutual interaction of stated phases creates the wear resistant material which can be used owing to the polyurethane elasticity in the sphere of a cementing or at creating the material surface layers.

Nowadays, there is a huge number of machine tools of various damage degree all over the world and it is necessary to renovate them. Some parts can be renovated by the adhesive bonding technology. However, it is necessary to quantify the degradation process. The aim of experiments was to set the influence of cutting fluid on the strength changes of adhesive bonds. In cases of satisfactory results it is possible to use with success the adhesive bonding technology for the renovation of damaged parts of machine tools. On the basis of the performed experiments it can be said that the resultant strength of adhesive bonds decreases during the time at simultaneous acting of the cutting fluid. From the experiments results the same influence on the degradation process of various adhesives was not proved. It came to a stagnation of the adhesive bond strength decrease after 75 days on the average.

The article presents the microstructure and mechanical properties of magnesium steering wheels. These steering wheels are manufactured by high pressure die casting. High-pressure die casting (HPDC) is a very good process for making complex mechanical parts out of light metals like magnesium and aluminium alloys. However, in recent times, another light metal has come to the forefront in the quest for lighter vehicles and improved fuel economy. The most commonly used magnesium alloy for die casting automotive components is of the Mg-Al-Mn type. MgAl5Mn is a good purity magnesium alloy with good corrosion resistance, very good mechanical properties and good castability. Mg-Al-Mn based alloys such as MgAl5Mn and MgAl6Mn have better elongation and impact strength than MgAl9Zn, and they are mainly used for auto safety systems like wheel rims and steering wheels. Alloy MgAl5Mn is an alloy with outstanding ductility and energy absorbing properties combined with good strength. This alloy, in the solid state, contains a solid solution α and the intermediate phase Mg17 Al12.

Machinability of materials is evaluated by different criteria. The basic evaluative criteria are based on tool wear. However, there are other criteria, for instance chip formation, cutting temperature, forces of cutting, etc. Machinability for different criteria depends on many factors, of which the most important is the chemical composition of the material. It is possible to divide machinability tests into two groups: Long-term tests and short-term tests. Short-term machinability tests are less objective than long-term ones, but they have the advantage of short duration and lower material consumption. This paper is focused on the experimental determination of the effect of chemical composition on the machinability of aluminium alloys. For testing three different short-term tests were used. The results were evaluated by correlation coefficients. All used tests led to the same results.

The paper dealt with the influence of geometric asymmetry on the vertical vibration of symmetrically or asymmetrically loaded mechanical system. The system is composed of rigid flexibly linked elements. Kinematic excitation was carried out by a unit jump (jump of the springs), excitation of system was symmetric and asymmetric. The system of elements was examined experimentally and numerically. The numerical model was verified by experimental solution. Numerical solutions were carried out by finite element method (FEM) applied to model that respected the design and conditions of the laboratory model for experimental investigations. The aim of the work was to create a numerical model based on the finite element method and to verify the results of the model. The obtained results can be applied to flexible storage machines.

With increasing tendency of die castings production, also the possibility to produce castings with maximum usage of molten metal grows. Residual of non-used molten metal, e.g. sprues, feeders, splashes and saw-dusts are used in next production as returning material. With returning material a lot of non-suitable elements is brought into the melting process, but with decreasing of input costs it creates inseparable part of production process. Usage of returning material in melt production has negative influence on final quality of produced castings, because of bringing of inheritable properties into produced melt. Important factor in melt production with the amount of returning material is to know to set its optimal amount and the way of melt treatment to achieve the same results in casting quality in comparison to the casting production from clean materials.

ŠKODA VÝZKUM s.r.o. (now Výzkumný a zkušební ústav Plzeň s.r.o.) cooperated on the development of the NEOPLAN DMA low-floor articulated trolleybus intended for the Boston city (the United States). Multibody models and finite element models of the trolleybus were utilized in the stage of the vehicle design. The multibody models of the trolleybus were created in the Alaska simulation tool and the simulations (running over a large road unevenness, start, braking and driving through a bend) were aimed at determining forces acting in the trolleybus suspension elements and radius rods. Time histories of the forces calculated using multibody models were used as the input data of the trolleybus finite element models. Utilizing the finite element models the critical places of the trolleybus body structure from the point of view of high stresses were determined. At the measurement with the real trolleybus prototype these places were provided with strain gauges.

Extraordinary properties of magnesium alloys, biodegrability and low density guarantee that these alloys are suitable for using in medicine as bone implants. So far there have been used alloys of titanium, cobalt and stainless steel for this purpose. Among the mentioned materials the magnesium alloys are winning because of their mechanical properties, which are more similar to human bones and at the same time there is the possibility to reduce the number of surgeries because of the spontaneous implant disintegration. Pure magnesium reaches neither the requested mechanical properties nor the corrosion resistance. That is why people are searching for elements, whose supplement would improve these magnesium properties to acceptable values. In this paper there was examined the influence of alloying elements (zinc, yttrium) on mechanical properties, the shape and the size of pores in the structure of magnesium alloys. Apart from alloying elements, a pores creating agent was also added to create pores with the diameter of more than 200 μm in the structure of magnesium alloys. Pores of this size allow the bone cells to grow in the implant and enable its gradual replacement by the bone. All samples were prepared by the method of powder metallurgy.