Solid State Phenomena Vol. 199

Abstract: The objective of this study is to reveal the influence of the lead angle variation on tool wear in the process of face milling of compacted graphite iron with ceramic cutting tools. To achieve this goal, 36 milling experiments were carried out with different lead angles, cutting speeds and feed rates at the 2.5 mm constant depth of cut. The tool flank wear was strongly affected by the lead angle variations. SEM analyses of the cutting inserts were performed and experimental results have been modelled with artificial neural networks (ANN) and regression analysis. A comparison of ANN model with regression model is also carried out. The R² values for testing data were calculated as 0.992 for ANN and 0.998 for regression respectively. This study is considered to be helpful in predicting the wear mechanism of the ceramic cutting tool in the machining of compacted graphite iron. A quicker method for the estimation of tool life is proposed, which requires less consumption of workpiece material and tools.

Abstract: The specific properties of TRIP steel can be obtained by the occurring the effect of additional plasticity during transformation of metastable retained austenite into martensite caused by plastic deformation process. Research carried out for highly alloyed austenitic steels with TRIP effect proved the influence of strain intensity, chemical composition and deformation temperature on efficiency marteniste transformation. In the work research concerned with the influence change of drawing speed on retained austenite amount in drawn wires structure was shown. In available literature there are no publications concerned with the influence of wire drawing process parameters on the structure evolution the medium carbon TRIP steel wires. Research shown in the work was realized with the assumption that the strain intensity is determined by scheme of single and total reductions, and the value of strain rate is a result of used in wire drawing process drawing speed.

Abstract: The paper presents effect of burnishing broaching process on the geometric structure of the steel tubes. Burnishing is a plastic surface treatment. Processing tools are hard and smooth surface. Burnishing elements of are ball, roll and disk. Burnishing be flat surfaces, and cylindrical shape. Burnished surfaces are cylindrical outer and inner. Because of the type of the force can be divided into static and dynamic burnishing. Due to the kinematics can be divided into sliding and roller burnishing. Occurrence of moving parts in direct contact with the material qualifies for the group process of burnishing rolling. The sliding burnishing design element property is part of the work surface burnished permanently attached to the handle. Burnishing is used as a finishing strengthens and smoothness, can be realized on the universal machine tools and machining centers, effectively replaces the machining operations such as grinding, reaming, honing and lapping.

Abstract: In the paper researches results of corrosion properties of Ni-Al alloy and Ni-Al-Al₂O₃ composite coatings were presented. Coatings were obtained by plasma torch. The studies in 0.01 M H₂SO₄ and 3.5 NaCl environments were realized. Measurements were made following methods: polarization and impedance spectroscopy. Rated coatings are more resistant to the 3.5% NaCl environment than the 0.01 M H₂SO₄. Corrosion current density for alloy coatings in artificial seawater was 19 μΑ/cm² and 28 μA/cm² environment acidic. Impedance spectroscopy studies showed that the alloy and composite coatings are characterized by greater charge transfer resistance in sodium chloride solution than in sulfuric acid solution. The value of corrosion potential in an environment of 3.5% NaCl is about 300 mV lower than 0.01 M H₂SO₄. Composite coatings Ni-Al-Al₂O₃ were characterized by a higher corrosion current densities and increased resistance than Ni-Al coatings in 0.01 M H₂SO₄ solution. It is related to the porosity of composite coatings. It was found little effect of oxide phase participation on corrosion current density and corrosion potential in 3.5% NaCl environment.

Abstract: Coatings were turned by two tools: a) ISO 2R 2525K10, geometry and cutting parameters recommended by Messner Eutectic Castolin Company (tool angle β = 90^o, approach angle κ_r = 45^o, nose radius r_ε =0,8 mm, clearance angle α = 6^o, rake angle γ = -5^o) b) bit tool with CBN WNGA080408S01030A insert mounted in DWLNRL-2525M08 holder (cutting inserts β = 80^o, approach angle κ_r = 95^o, nose radius 0,8 mm, clearance angle α = 6^o, rake angle γ = -6^o). The influence of cutting speed, feed rate, depth of turning on the coating surface roughness was estimated. The following cutting parameters: cutting speed V_c = 45 214 m/min, feed rate f = 0,04 0,196 mm/rev, depth of cut a_p = 0,05 0,3 mm. The lowest value of the roughness R_a = 0,5μm of the coatings were obtained by using cutting tools and parameters and bit tool: V_c = 214 m/min, f = 0,06 mm/rev, a_p = 0,3 mm.

Abstract: Most of the industry oriented research and development is based on conventional casting alloys Al-Si. This paper presents the results of deformation the hypoeutectic AlSi7Mg alloy used to manufacturing pistons for combustion engines. This is the material about high plasticity and corrosion resistance. For the research it was produced by semi-continuous casting process with magnetohydrodynamic stirring in crystalliser (MHD) and in conventional casting way. The results of deformation resistance of both materials have been described.

Abstract: Technology development and new grades of alloys creation put before construction materials the number of requirements in range of durability and reliability of created constructions. Receivers expect materials with high strength properties, low production cost of the finished product, availability, corrosion resistance and low specific gravity. So the specific needs of customers mean that studies are constantly associated with the exploration of new materials and technologies that could meet made requirements [1,2,. In large scale this demand is met through the use of non-ferrous metals and their alloys. Selection of appropriate manufacturing techniques and the use of heat treatment procedures allow to obtain materials with better mechanical properties. Here the leading role has the aluminium and its alloys. Due to specific mechanical properties aluminium based materials are used in almost each field of industry. In aircraft industry they are used for the manufacture of fuselage elements in automobile industry the light alloys are used to make cylinder blocks, and other elements of internal combustion engines. In the construction industry they are used to manufacture windows and doors, as well as beautiful self-supporting lightweight facades. While the aluminium alloy products such as films or cans are also used in the food industry. The combination of physico-chemical and mechanical properties of aluminium alloys makes them the optimal solution for innovative design, thanks to them engineers can provide high strength associated with very low gravity. This allows to minimize the costs of subsequent use of the product, and while achieving good strength parameters. As part of this work the analysis of strain rate and temperature impact on mechanical properties of the tested alloy will be carried out. The experimental studies conducted in the temperature range of recrystallization (test temperature: 400°C, 450°C, 480°C, 500°C) using two strain rates 1 s^-1 and 0,1 s^-1. This paper present the analysis of the application of high-temperature deformation changes in structure mainly caused by the dynamic recrystallization processes, which determine the optimal parameters of AlCuMg deformation process [. The proposed methodology of the research work made it possible to determine the effect of temperature-velocity parameters to changes in mechanical properties (inter alia: microhardness measurements) and changes in the structure of the material, which are closely related to the level achieved in mechanical properties.

Abstract: The results of corrosion properties research of aluminum alloy AW 7020 (AlZn5Mg1) welded by friction stir welding FSW were presented. Friction Stir Welding (FSW) a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the article the parameters for friction stir welding of sheets made of AlZn5Mg1 (7020) alloy was presented. The study was carried out in accordance with the requirements of the ASTM G 106. EIS measurement was performed in three electrode system in an artificial seawater (3.5% NaCl). Impedance studies were carried out at the corrosion potential. Changed voltage signal amplitude in the range ± 10 mV and frequency range of changes was as follows: 100 kHz - 0.1 Hz. Atlas 0531 EU & IA potentiostat was used for studies. The results of electrochemical impedance spectroscopy are presented in the form of parameters characterizing the corrosion process. Obtained results were statistically analyzed. The electrochemical impedance spectroscopy studies have shown that the joint welded by FSW has better electrochemical corrosion resistance than the native material - AW-7020 alloy. Original value are received results of the corrosion properties of new method friction stir welded AlZn5Mg1 alloy compared with the native material.

Abstract: The paper presents the results of microstructural research on GX12CrMoVNbN91 cast steel in the as-received condition (after heat treatment) and after the process of low cycle fatigue at room temperature. The microstructural tests were carried out by means of transmission electron microscope and completed with quantitative study determining: the mean diameter of subgrains, density of dislocations and shape factor. Performed research has proved that in both states: the as-received one, as well as after fatigue, the investigated cast steel is characterized by lath microstructure of tempered martensite with numerous precipitations of the M₂₃C₆ and MX type. Fatigue in the low cycle scope leads to the processes of recovery and polygonization of the matrix, as a result of a decrease in the dislocation density and an increase in the subgrain width. Intensity of these processes depends not only on the temperature of testing, but also on the level of total strain amplitude ε_ac. Stability of the substructure of the examined cast steel depends on the morphology of precipitates of M₂₃C₆, precipitated on the boundaries of grains/subgrains.

Abstract: The aim of this study is to determine mechanical properties and stress-corrosion resistance of EN AW-AIZn5Mg1,5CuZr alloy from the aspect of microstructure changes depending on the applied heat treatment. Stress corrosion is caused by the effect of corrosion environment parallel to mechanical stress. It occurs when cracks appear in the metal which is exposed to a corrosion environment and static stretching stresses. The effect of the corrosion environment and stresses on the metal surface cause cracks which are placed perpendicularly to the direction of stretching stresses and may be intercrystalline, intracrystalline or mixed. Stress cracking observations show that distinct cracks are often preceded by the incubation phase. The intensity of microcracks in this phase can be determined by examining changes in mechanical properties caused by changes in alloy structures after various time intervals of the stress-corrosion experiment. This study outlines changes in mechanical properties and resistance of the aluminium alloy in question depending on the heat treatment parameters. Changes in mechanical and corrosion properties are reflected in the structural changes of EN AW-AIZn5Mg1,5CuZr alloy. In order to enhance stress-corrosion resistance and obtain good mechanical properties in Al-Zn-Mg alloys (Zn+Mg>5%), a special heat treatment with cooling with a stop is used. This publication shows suitable heat treatment parameters which guarantee good mechanical properties and high stress-corrosion resistance.