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QP (quenching and partitioning) heat and thermo-mechanical treatment was applied to middle carbon, low alloyed CMnSiCr steel. Various numbers of deformation steps and different heating and cooling rates were tested for this steel. Two QP treatments were accompanied by subsequent annealing step at 250°C (QP-T processing). The effect of several processing strategies on mechanical properties and microstructures was determined by tensile tests and microstructure analysis was carried out by the means of scanning electron microscopy. Volume fraction of retained austenite was further established by X-ray diffraction phase analysis. The final microstructures were mostly martensitic with 18-24% of retained austenite and small amounts of fine bainite. High strengths above 1900 MPa were obtained for all of the treatments with ductility A5mm in the range of 12-19%.

Using of cutting inserts is currently a normal part of the manufacturing process. The article deals with the tool wear evaluation of selected inserts for turning by electron microscopy. Use of electron microscopy helps on closer analysis of machining consequences forthese plates, because the microscope images captured with electronmicroscope have a greater depth of sharpness and can display examined object with greater plasticity. It is yet another way to explore objects and extends the possibilities for obtaining large quantities of information. These analyzes were realized in other experiments performed at the Faculty of Production Technology and Management of Jan Evangelisty Purkyně University in Usti nad Labem. As a experimental material the hardened steel class 16 343 according to CSN 41 0002 has been machining.

The paper describes the analysis of two different worn-out tools of mulch devices. Both tools have been decommissioned due to missing of WC tips that have been soldered to the tool body. The tools body showed a significant signs of deformation. The input data of tools have been missing therefore it was carried out chemical analysis, hardness measurement and evaluation of material microstructure. Of the data collected has been identified material of tools and the heat treatment was proposed to increase the tool life. Then again followed analysis of the material to detect changes in the structure and mechanical properties. Consequently, we propose alternatives for improving of tools life. The first option is that forging can be heat treated. The second option is the exposed surface of the tool body can be heat treated by hardening as we marked through visualization of the tools. These ways should contribute to increased resistance to abrasive wear of functional surfaces of the tools.

Dimensional changes, or distortion, play a very important role in carburizing. To keep carburizing process productive and profitable, it is crucial that the resulting distortion is minimized. The purpose of this experiment was to carry out low-pressure carburizing and measure dimensional changes, residual stresses, characterize the resulting microstructures, and determine hardness in the specimens. These are the most important clues to the quality of the carburized layer. Experimental materials were the most widely-used carburizing steels: C15, 16MnCr5 and 15NiCr13. Residual stresses in the surface were determined by X-ray stress measurement.

Sound reflection of materials is influenced by many factors, e.g. by material type, density, thickness, porosity, angle of sound incidence, surface shape and excitation frequency of acoustic wave. The aim of the paper is to investigate the surface shape effect of expanded polyvinylchloride material on sound reflection. For this reason polyvinylchloride samples of different surface shapes and perforations were produced on universal and CNC machine tool. The material ability to reflect sound of the investigated polyvinylchloride samples was experimentally measured by means of the transfer function method on Kundt's impedance tube. The material samples were subsequently compared in terms of their sound reflection. It was verified that the highest sound reflection was obtained in case of the smooth surface polyvinylchloride sample.

The aim of the measurement was the observation (examination) and evaluation of the vibration impact on the technological head in the technology of abrasive water jet when changing the selected technological parameters, namely the feed rate of the technological head. The experiments were carried out on one kind of material - steel HARDOX 500 with a thickness of 10 mm. The impact of the change of the technological head's feed rate (400, 200,100, 50, 40 mm/min) on the size of the vibration acceleration amplitude and its frequency were examined. A database was created from the measured vibration values on the technological head and from that database the data was evaluated in selected softwares (LabVIEW, SignalExpress a Microsoft Excel). Graphical dependencies, frequency spectra covers and covers comparison graph were created from which new findings and conclusions were formulated.

This contribution deals with experimental cutting of samples made of special Alporas aluminum foam. This foam has been made by a powder metallurgy method and the foam resulting structure features very diverse material porosity. Test cuts through the aluminum foil were done using an non-conventional WEDM wire electro-erosive cutting technology. Monitoring and analysis of effects of proposed processing parameters on the resulting cut quality was done as a follow-up. Achieved accurracy of individual samples and its repeatability was also evaluated. At the end of the contribution wire cutting of aluminum foam technology findings are summarized and possible recommendations for practice are presented.

Sandwich composites are well known for many years and its place among the construction materials have they deserved mainly due to very good mechanical properties related to their weight. These materials have been a subject for many researches, but very few of them were focused on the behavior of curved constructions in bend with respect to their specific shape (curvature). With increasing number of new materials and resulting possible material combinations, it is necessary to characterize performance of new prepared structures and also evaluate the effect of a shape on the behavior of sandwich constructions with regard to their material composition. Presented paper deals with an investigation of flat and curved beams of sandwich structures, which correspond by their material composition to those, used in transport industry. Specifically, the influence of curvature size on a change of bending properties of structures with specific material composition compared to flat constructions is evaluated. This influence is also investigated in terms of specimen clamping and type of bending test. Obtained results showed that properties of sandwich structures are dependent not only on size of curvature, bud also on core thickness. Moreover, these results can help designers, constructers or technologists with design, dimensioning or production of these materials for specific applications.

Grinding is one of the technologies for surface finishing of large scale of material. This paper deals with grinding of titanium alloy Ti6Al4V with silicon carbide grinding wheel. Ti6Al4V is the most widely used titanium alloy. Its utilization can be found in medical, aerospace, chemical and other industries. This experiment deals with evaluating of surface roughness after grinding. The roughness parameters (Ra, Rz) were measured on each specimen ten times. Also cutting forces were measured while grinding each specimen. All these measured values were evaluated and presentated in graphs.

The article deals with the issue of secondary aluminum alloys with higher iron content and the possibility of reducing the negative impact of the iron by adding certain elements (correctors of iron). This paper evaluated the impact of nickel on amount of gas and mechanical properties of AlSi10MgMn alloy with increased iron content. For evaluation purposes master alloy AlNi20 with concentrations of 0.1, 0.3 and 0.5 wt. % was used. The main conclusion is that the addition of nickel corrector appears to have positive influence on reducing the negative effects of iron. The next conclusion is that the addition of 0.5 wt. % AlNi20 according to the results in the paper seem to be most benefical.

There are a large number of special methods for exploring the internal condition of materials on the basis of eddy currents. A major use of this method can be seen in surface engineering, particularly in studying some state quantities of surface integrity. It is also an irreplaceable tool in surface engineering. The reason is that no other affordable method provides information on both the surface and the sub-surface regions, as the latter are difficult to reach by most other inspection methods. It must be noted that the sub-surface region is significant, and dictates, to a large extent, the behaviour of the overlying surface. This article explores a non-traditional application of eddy current inspection. This inspection technique is typically used for detecting discontinuities in material. The study presented here involves a use of this non-destructive testing method for studying work hardening in two metallic materials: EN AW-1090 aluminium alloy, and S235JR-C carbon steel.

The presented scientific article deals with cutting edges after cutting by laser beam. The article describes the characteristics of the laser beam the factors entering into the process of cutting by CO2 laser, and their interaction on the integrity of the cutting edge of selected technical materials - steel S23JR. The article includes experimental evaluation of the interaction of input factors and parameters on experimental samples with thickness t= 2 mm which were cut by applying different parameters for the accurate assessment of the impact for each selected technological parameters. The experimental part of this article deals with changes of speed laser cutting and cutting speed influence on HAZ width and hardness of cutting edges. The outcomes of this article may be the prediction and parameters settings recommended for laser cutting as regards of HAZ width and hardness of cutting edge.

The Inconel 718 type is a high-strength, corrosion-resistant, and hardenable alloy with good tensile, fatigue, creep, and rupture strength. Mechanical properties of this alloy are strongly depended on microstructure and from presence of structural features such are gamma double prime (γ''), gamma prime (γ') and delta (δ) phases. Mentioned phases precipitate at various temperature ranges and Nb content as well. The Nb content necessary for delta phase formation is 6 - 8%, the γ'' formation is 4% or higher. When is Nb content lower than 4% the γ' is formed. Heat treatment of such alloys is commonly reported with T-T-T diagrams (Time-Temperature-Transformation). Temperatures above 700°C cause transition of metastable gamma double prime (γ'' - Ni3Nb bct ordered D022) into more stable delta (δ - Ni3Nb orthorhombic) but due to its morphology less desired. The Low Cycle Fatigue (LCF) tests were provide at room temperature via three point flexure loading on Zwick/Roell Amsler 150HFP 5100. After fatigue test the S-N curve was ploted and SEM fractography was done as well.

The article deals with the internal defects identification and characterization in butt weld joints by non-destructive ultrasonic Phased Array and X-ray technique. Basics of ultrasonic and X-ray testing are described in the theoretical part of manuscript. Phased Array and X-ray technique are volume nondestructive methods that can detect internal defects without breaking of construction. Ultrasonic Phased array and X-ray test procedures and test results obtained in non-destructive testing of butt weld are shown in experimental part. Ultrasonic record, X-ray record and weld macrostructure are given for each identified weld deffect. Advantages and disadvantages as well as comparison of ultrasonic and X-ray testing resulting from experimental measurements are described in the end of this article.

This paper deals with non destructive evaluation of surfaces via progressive method based on Metal Magnetic Memory (MMM). The paper reports about the physical background of this technique as well as presents specific results of some tests carried out on industrial and laboratory surfaces. This method seems to be promising techniques for fast and reliable monitoring components exposed to the surface modification as well as degradation under the external mechanical and other loads. The paper also discusses some advantages and disadvantages of this technique and presents some examples in which real components are monitored by the use of this technique.

Equimolar NiTi alloy known as Nitinol, is a modern metallic material on which very high demands are placed. This alloy has been used for its unique properties, such as shape memory, superelasticity and pseudoplasticity. Nitinol also has very good corrosion resistance and applicability as a biomaterial. In medicine Nitinol is most often used in the form of stents, which are used as reinforcement bottlenecks in the cardiovascular system or gastrointestinal tract, ortodontistic wires, orthopedic terminals of micro invasive surgery tools, tools for endoscopy and apertures or aneurysms. Successful use is subject to a manufacturer's declared stable mechanical properties of Nitinol. These properties can significantly influence a hydrogen deposited in the alloy, both due to the manufacturing process itself so that the resulting exposure in the environment. It was shown that even very low contents of hydrogen in the alloy leading to a substantial reduction in plasticity and strength of Nitinol which may be one of the main causes of premature failure of medical implants in the specific environment of the human body.

An intermodal transport is nowadays an inseperable part of a transport system. Designs of longer wagons are the result of efforts to achieve universality, transport capacity increase, reducing of noise and maintenance needs. In this paper are presented results of selected parametres of a long goods wagon driving on a test track. The long goods wagon and test rings models have been created by using the ADAMS/Rail software. The analysed wagon has been equipped by the Y25 bogie. Simulations of the long goods wagon running have been performed on the model of railway test rings - VÚŽ Velim, Cerhenice. For the dynamic analysis of the long goods wagon have been selected two sections of the railway test rings. For the ride properties wagon assessemnt have been selected output signals of vertical forces Q, guiding forces Y and the Y/Q ratio. There have been detected, values of assessed parametes have not been exceeded the limited values and therefore wagon runnings have been safety.

Using cutting or forming taps during the production of internal threads represents the basic method of manufacturing these coupling structural components, which - in the case of smaller dimension internal threads - can be encountered in many manufacturing processes. To optimize the cutting process and forming of internal threads, and in favour of the final results of these operations, the right choice of technological conditions, process fluids and methods of their application in areas where the technological process is realized, is needed. An important aspect of the use of process fluids are relatively large operating costs, and in some cases also the adverse environmental effects. Therefore, one of the current trends is reducing the amount of process fluids used during machining operations. At the Department of Machining and Assembly at the TU of Liberec experiments were conducted and various technological methods of production of internal threads during the use of various types of process fluids and methods of their application in the technological process were compared. During machining and molding, technological process, the parameters and properties of the produced internal threads were evaluated.

This research aims to solve the issues of limited measuring range and great accumulative error in the digital assembly of aircraft parts. In this paper, we propose the use of array visual measurement technology for the assembly of large aircraft parts. First, the visual measurement space for large aircraft parts assembly is determined. Second, the visual measurement model for large aircraft parts is constructed. Then, the differences that occur in real-time to the global coordinates can be calculated by using the pre-assembly feature points of large parts and the measurement tools of an array visual system. Finally, the real-time simulation of the aircraft assembly process is conducted in ADAMS by the secondary development of the software. In addition, errors between the real-time assembly and the design model are solved, and then transmitted to the mechanical actuators, which in turn adjust their attitude to complete the assembly of the large aircraft parts. The results show that array visual measurement technology for the assembly of large aircraft parts is feasible and efficient.

Nowadays, constant pressure on enviromental aspects in the foundry industry is calling for an improvement in casting production. The almost not used inorganic binders are coming back to the fore. Into this group, among others, belong binders based on alcali silicate solutions, known as water glass. The new hot-curing binder systems were introduced by different binder manufacturers. In order to compensate dissadvantages of alkalic silicate binder, the systems and processes are working with additives and adjuvants which are contained in a binder itself or added in liquid or powder form to the sand mixture. This paper presents the ASK Inotec process and impact of silica sand granulometry on achieved core mixture strength, which is important from a core production and also from a decoring ability point of view. Experiment was performed in laboratory terms using standard equipment and conditions.

This article deals with the influence of different specific pressures on the heat flux from the casting into the mould. The determination of the heat flux at different crystallization conditions will be the basis for the simulation calculation of the solidification with the crystallization under pressure.
The article presents the results of the measured temperatures inside of the mold and casting by influencing of the crystallization pressure of 100 MPa. For comparison, results are also presented in gravity cast specimens. Also are presented pictures of microstructure that were observed near the surface of the casting. On the basis of the measured temperatures inside of the mold are calculated as a value of the heat flow from casting into the casting mold. The results of heat flow correspond with the evaluation result of the microstructure.

In order to ensure acceptable level of risk associated with exposure to airborne dust they should have been mainly technical and organisation measures at workplaces with enhanced occurance of dust. Local exhaust ventilation (LEV) belongs to principal engineering control for prevention of airborne spreading. The aim of the study was to assess the efficiency of LEV system used at mechanical workshop for controlling respirable fraction of dust during stainless steel grinding activities. Dust control effectiveness was assessed by determining personal exposure levels with and without the use of LEV system. Personal dust samples were collected using a photometer-type dust monitor. On the basis of results it can be concluded that LEV system significantly improved quality of workplace atmosphere at given workplace.

The article presents results of research in the field of prototyping - 3D printing. The authors are focused on polylactic acid material known by the abbreviation PLA, which is widely used in 3D printing method to produce objects. The tech-nology of successive layering of plastics and its solidification causes states of tension in printed objects and subsequently their deformation. That may even lead to torn the object from the print pad. The article deals with dimensions of the deformations at the specimen just in dependence on heating of the print pad. The authors also suggest a compromise solution between excessive deformation of underlying layers and therefore proportional change of physical dimensions of the object and low adhesion of the object to the underlying heating bed, which can be seen as cut off the object during the printing process as mentioned.

To increase the intensity of cooling the unconventional methods can be used, which enable to achieve quick and steady heat transfer from the injection mould and from the plastic product. This paper is devoted to the cooling method based on high cooling potential of liquid carbon dioxide that is included among the unconventional methods of mould temperature control system. The main objective of this paper is to evaluate the applicability of cooling with using liquid CO2 in the injection mould with regard to several aspects that have a direct impact on the final cooling efficiency. The practical experiment deals with the design of the shaped mould insert with the incorporated progressive cooling system by means of CO2 and its comparison with conventional tempering by water. The study is based on evaluations of the temperature profiles reached from thermocouples located in three positions in the injection mould and analysis of temperature fields measured on the surface of the product after its removal from the shaped insert. All the analyses were carried out for three cooling modes and before individual testing steps the technological parameters of cooling were optimized.

Secondary (recycled) aluminium alloys are still not widely used in the foundry industry, because of the higher amounts of impurities that require more strictly control of the manufacturing process. The most problematic impurity of aluminium cast alloys is iron, which is in alloy mostly present in form of hard and brittle intermetallic phases. Such phases are thought to be detrimental to alloy mechanical and foundry properties and have to be removed or modified to eliminate negative effects. Several techniques might be used to this purpose, from which the most beneficial seems to be addition of some elements, so-called "iron correctors". Influence of the iron correctors can be also analysed by thermal analysis that serve as a tool to prediction of solidification behaviour of the alloy. Influence of V, Cr and Ni (alone and in selected combinations) to solidification behaviour of AlSi10MgMn alloy with increased iron level is presented in this article. Selected iron correctors influenced temperatures of thermal arrests representing formation of primary aluminium, iron intermetallics and also eutectic silicon.

This work investigates issues of BTA drilling of deep holes with slenderness ratio L: D = 45/60 of high strength steels with a tensile strength of Rm = 1350/1600 MPa. Methodology for testing of surface when turning and boring deep holes after drilling accordingly, heat treatment, straightening annealing and stress relief, was based on the statistical monitoring of eccentricity surface deviation from the theoretical axis of the bore axis for instruments with changeable carbide cutting inserts with CVD/PVD coatings under operating conditions with the number of 30 pieces. Measurement results of eccentricity of surfaces for locating strips before and after machining (as in turning and drilling for more cuts) are statistically processed in tables and graphs, as well as the obtained and acquired results. Article presents the optimized parameters of BTA drilling. Originally used tools for drilling were upgraded by using carbide inserts of type 14.171.55-00/0400 or /0250 by Krupp WIDIA. Influences of factors are discussed, and the monitoring of factors that produce holes of desired eccentricity is presented.

This article is focused on the processing of steel materials by thermal cutting technologies - laser cutting. It analyzes the impact of technological parameters - cutting speed effect on the cutting surface quality. The goal is to define the parameters ensuring proper amount of heat absorbed into the material that does not affect the cutting surface to avoid difficultiesduring further processing - such as drilling, thread cutting etc.To determinethe effect of cutting speed on the quality of the cutting surface, it was necessary to measure an internal stress and a hardness of HVM. Internal stresses in the experimental part of the article was measured by the X-ray diffraction and the resulting values are shown in the graphs.In the article are also shown microstructures of selected samples after the laser cutting under the different cutting parameters.

This study was focused on an effect of the plasma treatment on a mechanical behaviour of false banana's fibres (Ensete Ventricosum). The aim of the experiment was to describe the tensile strength of Ensete Ventricosum fibres which were modified by the plasma surface treatment. The fibres of Ensete Ventricosum, originally from Ethiopian region Hawassa, were used for this experiment. The fibres were prepared in the length of 100 mm. The samples were modified by the plasma treatment. Plasma was generated from a plasma generator (Plasma Reactor KPR 200 mm RM 54) while supplying the reaction gas (oxygen) and maintaining the reactor's pressure at 0.1 Torr with the use of a vacuum pump. To determine the properties that depend on the discharge power and treatment time, the plasma treatment was conducted in the power range 200-350 W for 10-50 s. The maximum tensile force was measured immediately after the plasma treatment to determine the ultimate strength. The ultimate strength and the deformation were determined by destructive tests using the tensile testing equipment (Labortech, MPTest 5.050, sensing unit AST type KAF 50 N, Czech Republic) with a rate of deformation 5 mm min-1. Fracture surfaces of fibres were studied using a scanning electron microscope (Tescan Mira 3, Czech Republic). The samples were covered with a thin layer of gold using a sputter coater (Quorum Q150R ES, United Kingdom) before SEM observation.

Currently at our department - Department of Engineering Technology - Technical University in Liberec), we are under-tracking properties of copper alloys. This article is dedicated of the brass (Cu-30Zn), which is used for production of decorative castings. With production of decorative castings deal various foundries in the Czech Republic. The staff of these foundries for long periods gained a lot of experience in metallurgy and preparation of the copper alloy melts. In terms of our foundry there is little available literature data, which would characterize the crystallization and solidification of castings produced from single and multicomponent brass. Our department is involved in research of copper and its alloys. This article contains a description of crystallization of copper alloys (70%) - Cu-30Zn and proving phase analysis structure of the production of test casting shape of desk in the sand mould.

Paper deals with problems of nanoparticles and nanomaterials applied in technical practice. In this time, we are looking for and examining ways of their best properties utilization. When being applied on the base material (metal, plastic, glass, incl. paper, cloth, etc.) In the form of very thin layer, then the base material can obtain very different properties, mostly advantageous, including improvement of their mechanical properties. To obtain these properties, it is necessary to apply nanomaterials in the form of very thin layer and for this purpose we need extremely fine granular nanoparticles that can be produced by means of fine milling technology. Resulting size, structure and shape of individual particles grains have the deciding influence on the successful application of these nanomaterials layers.