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Constantly increasing demands on mechanical properties lead to the search for new materials production technologies. The improvement could be achieved by methods of powder metallurgy, especially the ones capable to manufacture materials with ultra-fine microstructure. The aluminium alloy 7075, which belongs to the one of the strongest commercial aluminium alloys, was prepared by mechanical alloying in combination with spark plasma sintering. The thus-prepared samples were analysed (XRD, XRF, SEM-EDS, compression stress-strain test, Vickers hardness) and compared to its commercially produced equivalent (AA 7075). Mechanical alloying led to complete dissolution of all alloying elements in the aluminium solid solution. After SPS consolidation, the very fine intermetallic phase MgZn2 precipitated from the supersaturated solid solution and was distributed in the grain interior and at grain boundaries of the α-Al matrix. The very fine nature of the microstructure resulted in the increase of the compressive yield strength nearly 35 % to the commercial alloy and higher hardness.

The paper deals with welding joints and the methodology of increasing safety during austenitic chromium-nickel steels welding - type EN 10028-7 1.4301 (X5CrNi18-10). The technology of submerged arc steel welding 1.4301 using MAG enables a wider application of these steels in terms of the production of pressure vessels, but despite following all the safety regulations of heterogeneous welding stated in WHS, there might be an occurrence of melting defects of carbon parts through the welding of joints. The aim of this paper is to discuss the corrections of welding penetrations of the additional material during inhomogeneous welding, with the least possible destruction of the original material.

In modern times there are increasing requirements for quality of products in every part of manufacturing industry. In foundry industry it is not different and from the point of view of quality the most dangerous are hiden casting defects, such as shrinkage cavities. That is why a lot of foundries are researching, how to increase the efficiency of producing castings. This experimental work is dealing with search of the influence of carbon and silicon content in ductile iron on shrinkage creation. In the experimental part there is introduced the production process of test castings and results of ultrasound non destructive method. The object of this paper was to determine the influence of two main alloying elements of ductile cast iron on shrinkage creation with preserving specific strength of mould, which also has an impact on shrinkage creation.

This paper presents a kinematic and dynamic analysis and distribution of the stress in items of a planar mechanism by means of the MSC ADAMS software. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on the time. Distribution of the stress in the items presented is in [ Pa ]. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is great solution to use MSC Adams software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modelling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.

Main aim of this article and research is to describe exact influence of key parameter in injection molding process. This key parameter is temperature. Nowadays is possible to use wide range of advanced virtual simulation tools, which were in research used. Article is focused on determining optimal temperature of injected plastic material, temperature of mold and temperature of coolant. For veryfing of virtual method was performed real injection molding with same input parameters and results were compared. For evaluating of achieved quality was investigated influence on whole molding process and influence on final product properties. As testing material was choosen High-Density Polyethylene with properties described in article.

Laser beam welding is an industrial technology that has seen a significant development from the early stages up to the present. Technological process management ensures high product quality as well as enhanced productivity and competitiveness. The aim of the research is to determine the impact of welding parameters by fiber laser beam on the quality of weld joints from aluminium. Basing on the presented quality assessment methods and computer simulation, we evaluate the weld joint samples. Finally, we discuss optimal welding parameters and conditions allowing the production of weld joints of the desired properties.

Present work is focused on the study of recycled AlSi8Cu2Mn cast alloy. Furthermore, the effect of Sr-modification (0; 0.03 and 0.05 wt. %) on the microstructure, tensile and impact properties (UTS, ductility, hardness and impact energy) were investigated. For study and identification of intermetallic phases were utilized standard, colour and deep etching (in order to reveal the 3D-morphology of the Si-particles and intermetallic phases). For element composition of the specimen was used X-ray analysis. Finally, the effect of Sr-modification on silicon morphology was examined. The results show that the addition of Sr into AlSi8Cu2Mn cast alloy should act as a modifier, so it supposes to change the eutectic Si-morphology. However, its effect as a Si-modifier is not as significant. Higher number of iron (1.1 %) leads to an increase of precipitation of brittle iron phases with platelets (Al5FeSi) and skeleton-like (Al15(FeMn)3Si2) morphology. Al5FeSi platelets act as preferred crack sites and reduce the tensile and impact properties. Strontium not only refined and modified eutectic Si, but also modified the Al5FeSi needles and thereby improves tensile (first of all ductility) and impact properties. Sr addition is also associated with porosity formation.

During the metal machining amount of dust is generated which can influence significantly surroundings, but mainly workers are exposed to dust pollution. The aim of this paper is to present results of microclimatic research focused on dust pollution in workshop during the milling of aluminium alloy workpieces. The concentration of air dust was measured by the DustTRAK II Model 8530 aerosol monitor. Using the special impactors the PM1, PM2.5, PM4, PM10 size fractions were also measured. Obtained results of measurements and concentrations of different size of dust particles were analysed. Results of measurements under different milling conditions are generalized. The conclusion of the research is that it is necessary to watch the optimization of the milling process as well as secondary effects of the technological operations and inner environment of workshops which can be contaminated by chemical substances as well as dust particles.

Manganese is the most widely used and it can modify the β-Fe platelet-like morphology to more compact and harmless forms (i.e. Chinese script, skeleton-like and/or polyhedral α-Fe phase) Furthermore, the Mn and Fe content can influence the type, the size and the ratio of different Fe intermetallic compounds. The present study investigates the effect of manganese concentration on the formation of iron compounds in an AlSi7Mg0.3 with levels of iron 0.3 and 0.7 wt. %. The manganese was ranking in amount of 0.1, 0.2, 0.6 wt. %. The morphology iron intermetallic phases has been investigated using cooling curve analysis, optical microscopy and scanning electron microscopy (SEM). Can be concluded, that increased amount of manganese lead to decrease the temperature of solidification iron rich phase (TAl5FeSi) and reduction these particles.

Modern cutting tools with high quality attributes are very important factors for companies that want to increase their production efficiency and product quality. Cutting tool properties include high durability, endurance and cutting power. Quality shapes and surfaces of cutting edge micro and macrogeometry are also important. This article deals with cutting edge microgeometry on sintered carbide end mill tools. Drag finishing technology is used for preparation of cutting edge microgeometry. Two process media are used during the experiment. Due to the different process media, the final surface quality will also be different. Nowadays, cutting edge preparation is one of the basic but inseparable parts of development and production of cutting tools. Microgeometry quality affects the behaviour of cutting tools during the machining process. The behaviour mainly includes cutting forces, friction and vibration. The impacts of drag finishing on the functional surfaces of the cutting tool are investigated in this article. An IFM G4 microscope is used for measuring the cutting edge microgeometry.

Main aim of this article is description of weld line influence on mechanical properties of plastic parts. Special design of mold was created for this research. This mold is able to create specimens with and without weld lines. These specimens undergone tensile test according standard ASTM D638 with different results. Strength and strain results were compared for both types of specimens. Nylon PA6 without any internal reinforcement was used as reference material during testing. Both specimens were investigated also by microscope in order to see composition of weld line and plastic material. Microstructure showed geometry of weld line and also fracture surfaces indicated presence of plastic deformation

The article describes the possibilities of vehicle passability testing by the help of computational simulation. It is used here computing simulation system ADAMS AVT. The simulations can help to find quick answers to basic and additional questions of design change influences in the area of testing vehicle passability. The first part of the article contents description of partial computation simulation models construction which the calculations are associated with. There are mentioned the binding conditions of calculations also. There are mentioned and evaluated the results of performed simulation calculations in the second part of the article. These calculations are performed in order to find out an influence of operation conditions on the vehicle passability. Real operation condition is invasive vehicle speed into a slope in this case. Under investigation are the changes of beaten distance uphill that is the vehicle able to overcome.

Results of an experimental research of friction coefficient in "alumina ceramics - quartz glass" friction pair are presented. The research with pin on disc test configuration using SRV-III test machine was carried out at loads from 10 to 1000 N, constant sliding velocities 5 mm/s; ambient temperature 23°C and relative humidity 30%. The obtained results reveal that in general, friction coefficient for "alumina ceramics - quartz glass" pair decreases with the increase in normal load. It is shown that the obtained friction coefficients values at the normal force from 100 to 1000 N for the given experimental conditions can be used to pre-estimate the interference fits in "alumina ceramics - quartz glass" friction pairs.

Article deals with design of welding jig for assembly of wind power plant component. Mainstay of article is design of welding jig, which makes exactly setting and reliable clamping of individual parts of welded desing possible for their complete welding. Design procedure of individual parts of welding jig is described in details in view of their functionality. Paper is especially focused on the parts of welding jig, which are necessary to make, including material selection of individual parts. Finally the technical and economic evaluation is carried out, approximate cost of jig is calculated and financial savings associated with practical use of welding jig are evaluated.

The purpose of this paper is to provide an overview of state-of-the-art of maintenance management audit and to show a case study of maintenance audit and its results in the Czech Republic. Authors proposed audit methodology based on world and own experiences. It was defined hundred thirty audit criteria divided into ten maintenance management areas. Using expert approach to review of maintenance managers and documentation according to audit criteria enables to obtain answers and their assessment presented in percentage of audit criteria fulfilment. After that there is applied SWOT analysis method to determine mainly weakness (gaps) in real maintenance management processes comparing with world excellence maintenance class. On the base of the gaps there are recommended topics for maintenance improvement. Value of the results is a help to maintenance managers and supervisors in maintenance audit executing as a tool for maintenance management improvement.

The article deals with the determination of the life of the lubricant based on the determination of the degree of wear or deterioration of the engine oil by wear particles. Non-ferrous particulates of a large diesel engine and their determination based on laboratory tribotechnical diagnostic tests are characteristic for the purposes of article. The combination of Atomic Absorption Spectrometry and Thin Layer Chromatography is used for measurements. The statistical method of discriminatory analysis is used to evaluate the article. The lifetime of the lubricant is thus determined according to objectively determined criteria realized by normalized and customized analyzes of the lubricant at a high degree of accuracy. The proposed and verified method demonstrates the degree of achievement of individual lubricant wear limits of non-ferrous metals in a large compression-ignition engine. The clear advantage of the proposed method is the precise determination of the optimal oil change interval and the possibility of early detection of a vehicle defect.

Reverse engineering is a technology that enables acceleration of data collecting for CAD, CAM, CAE systems, which also means shortening time of development, construction and components production. It is a transfer process of a physical component to a digital format. Generally, the technology of reverse engineering means a conversion of analogue data to digital data that are further processed. Every single industry branch rising their requirements on accuracy, dimension, quality, etc. Therefore, digitisation is applied in many production fields such as an automotive industry, aircraft or shipping, medicine, industrial design, design, etc.
An article deals with an analysis of prototype models of gears in various stages of production. The realized inspection of a shape of prototype gears lied in uploading of a digitised referential CAD model (the gear after heat treatment and machining), subsequent setting up of digitised prototype gears (the gear after the machining, gear after heat treatment) in respect of this referential CAD model, a control of their dimensions and forming a colour map of deviations in chosen points.

Selective laser melting (SLM) is the most widespread method of additive manufacture of metallic materials. Products are build up by selective melting of input powder material and joining it together successively in thin layers. The additive approach brings along many advantages of which the geometry freedom is the most outstanding and the most appreciated. Nevertheless, despite intensive research in the domain of additive manufacture, there are still some problems, such as insufficient shape precision and surface quality or occurrence of internal defects. These imperfections are related to a high number of variables entering the production process. Present paper thus deals with the influence of various process conditions on final product quality. Specifically, it is focused on preparation of tensile test samples of titanium alloy Ti6Al4V in three different orientations - horizontal, vertical and inclined. Mechanical properties documenting part quality along with microstructure analysis have shown that especially the material plasticity is strongly affected. Porosity, microstructural anisotropy and surface quality are all contributing factors.

The utilisation of pure molybdenum in high-temperature applications in a vacuum requires very precise machining. Considering the fact that conventional machining methods do not achieve the required geometrical and dimensional accuracy in several cases, it is necessary to use the unconventional technology of wire electrical discharge machining (WEDM). This study aims at analysing the surface and subsurface layer of pure molybdenum after WEDM in terms of the occurrence of defects. Profile and areal parameters were evaluated by means of a contact 3D profilometer. The occurrence of individual defects both on the surface and underneath it was studied by means of the methods of electron microscopy and focused ion beam (FIB). Furthermore, the local chemical composition of the surface of the workpiece (EDX) was determined.

The paper presents the strength tests results of joints made by use of two hot melt adhesives. The tests were carried out according to the modified standard ČSN EN 1465 (66 8510) and ČSN EN 205 (66 8508). For bonding the three-layer plywood of 4 mm thickness was used. The test samples of 100 x 25 mm size were cut out from a semi-product in the direction of its longer side, in the oblique direction and in the direction of its shorter side. The specimen pairs were bonded using the hot melt glue gun. All assemblies were loaded up to their destruction. The destructive force and the destruction type were registered. From the results of carried out tests evaluation it follows that hot melt adhesives can be recommended for bonding plywood. The bonding strength of bonded joint is comparable to the strength of the bonded material. Finally the technical-economical evaluation of the experiments was carried out.

Article deals with design of jig for welding of rail-borne door system on the basis of model and drawing of window frame. Using this jig is ensured right setting and reliable clamping of two bent profiles. By welding of these profiles is made a window frame of automatic door systems for rail-bornes. TIG method is used for welding. Article describes and explains setting and clamping of window frame into jig. Design of control jig for window frames of similar type is embodied in text too. Control jig helps by dimension measurement of window frames.

The article deals with testing of the resistance against Foreign Object Damage (FOD) on leading edges of blisks (blade disks) in turboprop engines made of Ti6Al4V alloy. Such damage can occur during operation, when rapidly rotating compressor parts on the engine intake are exposed to foreign particles. E.g. operation of small passenger aircrafts in desert areas, where large amounts of foreign particles occurs in the atmosphere. The paper describes the development of method for testing the resistance of the leading edge of the blades against FOD in order to mimic the conditions of operational damage. Further it quantifies potential benefits of modification in the geometry of the blisk leading edge and compares results of FOD resistance of sharp leading edge and modified geometry. Results of metallographic analysis for deformed areas near the FOD on Ti6Al4V alloy are also presented.

DEFORM™ is a robust modelling software tool which uses the finite element method (FEM) for modelling technologies in 2D and, naturally, in 3D. One of the processes, the modelling of which DEFORM™ supports, is slab milling.
For this purpose it uses an advanced FE model with various parameters, such as the fracture criterion. If their values are not chosen correctly, the desired results cannot be obtained.
A 3D simulation model was developed to explore the capabilities for entering data, calculating and evaluating temperature distribution within a workpiece during experimental milling carried out under real-world cutting conditions. The FEM model concerns the temperature on the rake face of an exchangeable cutting insert. The primary aspect which was monitored was the temperature field during chip formation.
Finally, the results of the simulation were compared with data from a machining experiment. The material used for the simulation and for the machining experiment was the ČSN 12050.1 / AISI 1045 steel.

This work deals with the problematics of cutting forces when drilling holes in Inconel 718. Drills with different geometries of cutting edge were used. The cutting forces and torques were measured during the experiment. The feed cutting force had the greatest influence of all the cutting forces, therefore only the cutting force feed was evaluated. The torque was monitored. This material is known for its unique properties of high strength at high temperatures, corrosion resistance, high hardness, work hardening and low thermal conductivity. Part of the paper is focused on the experiment where the effects of the geometry of the cutting edge on cutting forces are evaluated. This paper is limited only to carbide tools. The results of the experiment are compared with results from other research institute.

Machining of titanium alloys meets with poor life of a cutting tool. It is caused by a low thermal conductivity and by a high strength-to-weight ratio of the alloys. Various approaches for cost-effective and productive machining titanium alloys are still researched. One of methods can be using the cutters made of modern high-speed steel (HSS) as a product of a powder metallurgy (PM) process. These materials (PM-HSS) possess better and homogenous mechanical properties than conventional high-speed steel. The PM-HSS cutters equipped with any effective coating allow increase cutting speed to the level which is typical for uncoated cemented carbide, while price of the tool is lower. In the article several PM-HSS cutting tool materials were compared to conventional cobalt based HSS from the tool life point of view. It was proved that conventional high-speed steel offers very long tool life and high tool performance at speed of 30 m/min. However the regular tooth pitch significantly decreases tool life for this cutting tool material. The main benefit of PM-HSS cutters can be fully utilized when cutting speed about 50 m/min is applied. The cutters coated by effective thermal barrier showed longer tool life and higher performance of the cutting tools.

This paper presents an improvement to the mechanical and tribological properties of aluminium alloys. AlSiN and AlCrSiN coatings (with different Cr content) were deposited on substrates of Al-Cu-Mg alloy by the cathodic arc evaporation method at 400°C. Surface morphology and chemical composition were estimated by a scanning electron microscope equipped with an energy dispersive spectrometer and mechanical profilometer. The increasing chromium content in the coating led to an increase in the coating hardness. The tribological behaviour of the coated and uncoated Al-Cu-Mg alloy samples was examined using the "Ball-on-Disk" method (ASTM G99-95) at a load of 10N using Al2O3 ball as a counterpart.

The article deals with some aspects related to the machining of surfaces that have been deposited by wear-resistant hard coats using HVOF (high velocity oxygen fuel) technology. HVOF coating is a thermal spray process used to improve a component's surface properties, thus extending equipment life by significantly increasing errosion and wear resistance, along with corrosion protection. For a purpose of this research, the chromium-cobalt alloy - Stellite 6 was used as a sprayed material. Considering that the parts made of stellites are widely used in various industries and very popular in specific applications, it is a big drawback that adequate machining processes for stellites have not yet been developed other than the costly and time-consuming technique of grinding. However, in this research, an attempt has been made to reveal the optimal machining parameters for a lower value of surface roughness for the purpose of successful machining of Stellite 6 using inserts with various radii of cutting edge. Authors have evaluated the quality of machined surface not only by means of Abbott curve, but they have also observed the dependency of arithmetical mean roughness value on both cutting-edge radius and feed. The analyses of cutting tips wear at changeable inserts have shown that typical wear appears in the form of a notch.

This paper considers the assessment of attenuation in aluminium alloys castings prepared by gravity casting method and under pressure. The issue of ultrasound attenuation is important in setting the conditions of non-destructive testing, especially in casted materials. The characteristics of the ultrasonic technique, the calculation of the attenuation and the velocity of ultrasound are presented in the theoretical part of this paper. For experimental measurements, cylindrical castings from AlSi alloy were made. The ultrasonic records of the casting control, the calculation of ultrasound attenuation for individual samples as well as the microstructures are listed and described in the experimental part. The evaluation of measurements and comparison of calculated ultrasound attenuation is at the end of this article.

Nowadays manufacturers currently use about 35 % of secondary aluminium and about 65 % of primary aluminium to meet their needs. The production of secondary Al alloys have significant advantages. Most important is saving of natural resources with a consequent material cost reduction and a considerable energy-saving associated to reduction in pollution and CO2 emissions. The positive fact is that secondary Al alloys has comparable mechanical properties with primary aluminium alloys. Therefore it is necessary to study properties such alloys especially those which are used for transport industry in order to keeping the quality of casting. One of the major properties of casting for transport industry are fatigue properties. Research point to the fact that more than 90 % of broken engineering components are fractures caused by fatigue of used material. Extremely dangerous are fatigue fractures in transport, for example rails, tire parts, plane wings and hulls of ships, because these are usually connected with human casualties. Due to this fact were studied fatigue properties of aluminium alloys used especially for automotive castings - AlSi9Cu3. The great object was influence of casting to the different mould (sand and metallic) without modification, heat treatments or grain refinement of experimental material to fatigue resistance of the casting. This work shows differences between materials properties which were casted into the different mould.

Thermal treatment of the aluminum alloys significantly affects their final mechanical properties. However, the process of such thermal treatment is influenced by many variables and the correct choice of these technological parameters is a prerequisite for achieving their required properties in the manufactured part. This paper evaluates the effect of thermal treatment conditions on the time course of hardness for EN AW-6082 alloy during artificial aging. For the experiment, the solution annealing temperature of 520°C was chosen in combination with three different holding times at this temperature and then also 3 different initial temperature of the material before cooling in water. The effect of the thermal treatment parameters was subsequently monitored by the Brinell hardness time course at 3 selected artificial aging temperatures.