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EN
The paper presents the result of tribological test of ABS and steel samples sliding under dry friction. Polymeric samples were manufactured of ABS material using FDM technology. Testing was carried out in unidirectional sliding in a ring-on-flat contact in a PT-3 tribometer. The scope of tested parameters included volumetric and mass wear, the friction coefficient, and polymeric specimen temperature. Polymeric specimens used in the study were manufactured at various settings of the 3D printing process such as the orientation of the specimen in print with respect to the printer building tray and the thickness of a single layer of the deposited material. Comparisons of the impact of these parameters on tribological performance of the sliding contact were analysed.
PL
Przedstawiono wyniki badań tribologicznych pary ABS – stal w warunkach tarcia suchego. Polimerowa próbka została wykonana z materiału ABS przy użyciu metody FDM. Testy jednokierunkowego tarcia w układzie pierścień – tarcza przeprowadzono na Tribometrze PT-3. Analizowanymi parametrami były zużycie masowe i objętościowe, współczynnik tarcia oraz temperatura próbki polimerowej. Próbki polimerowe zostały wyprodukowane przy różnych parametrach procesu druku 3D, takich jak: orientacja próbki w stosunku do platformy drukarki oraz grubość drukowanej warstwy. Przeprowadzono szczegółową analizę wpływu tych parametrów na charakterystyki tribologiczne badanego skojarzenia ślizgowego.
EN
A new interpretation and a quantitative description of abrasive wear of solids are proposed in this paper. The well-known J.F. Archard’s dependence, commonly applied by tribologists to describe volume of a worn material as a function of real contact surface between bodies, serves as the starting point for the discussion. The dependence characterises adhesive wear whose intensity is restricted to certain energy-conditioned values. However, greater wear intensities can be observed in abrasive wear. The quantity of energy required to separate a unit of volume (mass) of a rubbing material is also lower in the case of abrasion than of adhesive wear. It is claimed, therefore, that the principle of straight proportionality between volumetric wear and real contact surface of bodies cannot be used to characterise the wear mechanism. The process of detachment of a worn particle in the form of a chip is related to a certain volume, while the density of the flux of removed material is related to an apparent machined surface, which is in a specific relation to the nominal contact surface of rubbing solids. The proposed new physical model and the analytical description of metals’ abrasive wear are illustrated quantitatively with results of the author’s experiments.
PL
W pracy zaproponowano nowy sposób interpretacji i ilościowego opisu zużywania ściernego ciał stałych. Za punkt wyjścia do rozważań przyjęto powszechnie znaną i stosowaną w tribologii zależność analityczną J.F. Archarda opisującą objętość zużytego materiału jako funkcję powierzchni rzeczywistej styku ciał. Zależność ta charakteryzuje zużywanie adhezyjne, którego intensywność jest ograniczona do pewnych wartości uwarunkowanych energetycznie. Podczas zużywania ściernego obserwuje się jednak większe intensywności zużywania. Również ilość energii potrzebna do oddzielenia jednostki objętości (masy) trącego się materiału jest mniejsza w przypadku zużywania ściernego niż – adhezyjnego. Dlatego w niniejszej pracy stwierdzono, że zasada prostej proporcjonalności zużycia objętościowego do powierzchni rzeczywistej styku ciał nie może być utrzymana dla scharakteryzowania mechanizmu ścierania. Proces oddzielania się cząstki zużycia w postaci wiórka odniesiono do pewnej objętości, a gęstość strumienia masy usuwanego materiału – do umownej powierzchni skrawania, pozostającej w określonym związku z powierzchnią nominalną styku trących się ciał. Zaproponowany nowy model fizyczny i analityczny opis zużywania ściernego metali zostały zilustrowane ilościowo na przykładzie wyników eksperymentalnych badań własnych.
EN
The paper presents the results of an experimental study on adiabatic shear bands (ASB) in two grades of steel with three different microstructures. Samples were subjected to impact forces in order to obtain a targeted shear band. The process of deforming the samples was carried out with a bar impact rod moving at high speeds in the range of 1.4 m/s to 16.5 m/s was carried out. Microstructural studies of deformed samples were performer using the Electron Backscatter Diffraction (EBSD) method. The results of the experiments show that the ASB type depends on the initial microstructure of the material and the deformation speed. It has been shown that, depending on the type of microstructure, ASBs are characterized by a different mechanism of formation and show different character.
PL
W artykule przedstawiono wyniki badań doświadczalnych adiabatycznych pasm ścinania (ASB) w dwóch gatunkach stali o trzech różnych mikrostrukturach. Próbki poddano działaniu sił udaru w celu uzyskania w materiale ukierunkowanych pasm ścinania. Przeprowadzono proces odkształcania próbek siłą udaru pręta poruszającego się z prędkością w zakresie od 1,4 m/s do 16,5 m/s. Badania mikrostruktury obszarów próbek poddanych odkształceniu wykonano metodą dyfrakcji elektronów wstecznie rozproszonych (EBSD). Wyniki eksperymentów wykazały, że rodzaj ASB zależy od mikrostruktury początkowej materiału oraz prędkości odkształcenia. Wykazano iż w zależności od rodzaju mikrostruktury ASB charakteryzują się odmiennym mechanizmem powstawania i wykazują odmienny charakter.
PL
Wodór w stali jest pierwiastkiem szkodliwym. Pogarsza właściwości wytrzymałościowe, obniża właściwości plastyczne, a także jest odpowiedzialny za kruche pękanie stali. Źródłem pierwiastka w kąpieli metalowej mogą być cząsteczki związków wprowadzonych do roztworu wraz ze wsadem, również wilgoć pochodząca ze wsadu lub wodór pochodzący z powietrza. We współczesnym przemyśle stalowym stosowane są różne metody usuwania wodoru z ciekłej stali na etapie jej wytwarzania. Najbardziej skutecznymi metodami są metody obróbki próżniowej. Z praktyki przemysłowej wynika jednak, że pomimo stosowania prawidłowych parametrów procesu odgazowania stali, w różnych porach roku uzyskuje się różne rezultaty. W artykule podjęto próbę wyjaśnienia tego zjawiska.
EN
Hydrogen is a harmful element in steel. It deteriorates the steel’s strength properties, lowers its plastic properties, and it is also responsible for brittle steel cracking. The source of the element in the metal bath can be molecules of compounds introduced into the solution together with the furnace charge, also moisture from the furnace charge or hydrogen from air. In the modern steel industry, various methods are used to remove hydrogen from liquid steel at the stage of its manufacture. The most effective methods are vacuum treatment methods. The practice of the process used in the industry shows that despite using the correct parameters of the steel degassing process, different results at different seasons of the year are obtained. The paper attempts to explain this phenomenon.
PL
W artykule przedstawiono wyniki symulacji numerycznej, której celem była identyfikacja ilościowa i jakościowa prawdopodobnych faz niemetalicznych powstających w wyniku oddziaływania ciekłej stali i odtleniacza – aluminium. Symulacja numeryczna wykonana w programie FactSage stanowiła wstępne badania przed procesem filtracji ciekłej stali przez wielootworowe filtry ceramiczne odtlenianej aluminium, jako jedna ze skutecznych metod usuwania wtrąceń niemetalicznych.
EN
The article presents the results of numerical simulation, the purpose of which was to identify quantitatively and qualitatively the probable non-metallic phases arising as a result of the interaction of liquid steel and deoxidizer – aluminum. The numerical simulation carried out in FactSage, was a preliminary study prior to the aluminum deoxidized liquid steel filtration process through multi-hole ceramic filters, as one of the effective methods for removing non-metallic inclusions.
PL
W pracy przedstawiono wyniki badań filtracji ciekłej stali przez wielootworowe filtry ceramiczne. Przedmiotem badań była stal wysokowęglowa z gatunku C70D. Proces przeprowadzono z zastosowaniem filtrów o różnej wysokości, a zarazem o różnej powierzchni filtracji, w układach filtru pojedynczego oraz podwójnego i potrójnego. Przeprowadzone badania miały na celu zbadanie procesu filtracji stali poprzez wyznaczenie ilości wtrąceń niemetalicznych i ich udziałów powierzchniowych przed i po procesie filtracji. Kolejnym etapem badań było określenie skuteczności filtracji względem ilości wtrąceń niemetalicznych i udziałów powierzchniowych.
EN
The paper presents the results of research on filtration process of high-carbon steel (grade C70D) through multi-hole ceramic filters. The process was carried out using filters with different highs - single filter, double and triple filter system. The research was aimed at determining the amount of nonmetallic inclusions and their surface shares before and after the filtration process. The next stage of the study was to determine the filtration efficiency relative to the amount of non-metallic inclusions and surface shares.
EN
In the industrial sectors, pipelines have been used as the most economical and safe means of transporting oil and gas (Pipelines). However, the number of accidents has increased considerably as their use has increased. As a result of the operating load and the pressure used, the thickness of the tube must be increased and the mechanical characteristics improved. This approach was applied to predict the growth of crack effect in samples of two pipelines at given thicknesses and pressures. We created cracks with deferential dimensions in both API X80 steel pipelines, with an application of deferential internal pressures. For the simulations, we used the code ANSYS.
EN
In this paper, we use a phenomenological model based on the Jiles-Atherton-Sablik model of stress affecting the magnetic hysteresis of magnetic materials as modified when stress goes past the yield stress. We use this to show that (1) the model produces sharp shearing of hysteresis curves, as seen experimentally and that (2) it also produces a step in the hysteresis loss at small residual plastic strain. We also find that the step in the hysteresis loss can be fitted to a power law, and find that the power law can be fitted by the power m=0.270, different from the mechanical Ludwik Law exponent, and reasonably close to the experimental 0.333 and 0.202. We will also suggest a method of measuring how plastically deformed the material is by suggesting how the dislocation density can be measured.
EN
On a fragment of the rim of a railway wheel removed from service, the volume of the metal with non-metallic inclusions located near the tread surface was investigated. The use of the microhardness measurement technique made it possible to establish the nature of strain hardening of carbon steel near non-metallic inclusions. It showed that with a normal orientation of the plastic flow relative to the inclusion surface, the metal volumes undergo hardening. In proportion to the appearance of a fraction of the tangential component of the deformation near the nonmetallic inclusion, a decrease in the degree of hardening of the metal was observed.
10
Content available remote Gazy osłonowe do spawania metodą MIG/MAG. Cz. I
PL
W artykule omówiono rodzaj i skład gazów osłonowych używanych podczas spawania metodą MIG/MAG, jak również wyjaśniono powody występowania różnic w ich składzie w zależności od materiału spawanego i obszaru stosowania.
EN
The type and composition of shielding gases used in MIG/MAG welding are discused, as well as the reasons for the differences in their composition depending on the parent material and field of applications are explained.
EN
Austenitic stainless steels are often used for a materials in the construction of machines and equipment for agricultural and for industrial construction. One of the most important factors constructional material is corrosion resistance. Equipment with austenitic stainless steel can be easy join by quickly welding at a not to high construction price, but one with the serious problem in aggressive environment is their corrosion resistance. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, round-section and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. The main aim of this research is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336 hours). For this used weight loss of test samples and its profile roughness. The research was conducted on austenitic stainless steel in grade in Nitrate acid at 333 K. Corrosion tests confirmed that the research this steel in 65% nitrate acid as a corrosive environments is characterized through proportionate to time corrosion process whose measure may be surface roughness. In industrial practice roughness parameters for all the research times can be used for determine the stage and size of steel corrosion.
EN
The lack of a common methodology on compaction theory stimulates developers of road construc-tion equipment to create various approximate methods for their calculation, the number of which, at the present time, is comparable with the nomenclature of the proposed designs of rollers. The article presents the analysis of the deformable shell behavior of a road roller, and the compacted material under its compacting roller, in a situation when a rigid circular shell of the roller is replaced by a forcefully deformable elliptical shape, which, unlike the circular design, allows variation, adjustment and optimization of the road roller impact on the material to be compacted.
PL
Kompozyt polianilina-rdzeń-nano-TiO2 został przygotowany w procesie polimeryzacji strąceniowej polianiliny w środowisku dwóch różnych kwasów nieorganicznych. Testy korozyjne zostały wykonane na podłożu ze stali S235JR pokrytej spoiwem alkidowym (jednowarstwowo, przy użyciu aplikatora ramkowego) zawierającym 0,5%mas badanego kompozytu, spoiwem alkidowym zawierającym 0,5%mas pigmentu na bazie polianiliny z rdzeniem oraz handlowego, antykorozyjnego spoiwa alkidowego. Badania w komorze solnej zostały wykonane zgodnie z normą PN-EN 9227:2012, a badania EIS wg normy PN-EN ISO 16773-2:2008. Testy EIS prowadzone były przez sześć tygodni z cotygodniowym pomiarem impedancji. Wyniki wskazują na najwyższą odporność antykorozyjną dla farb z wprowadzonym pigmentem na bazie polianilina-rdzeń-nano-TiO2, szczególnie dla kompozytów otrzymywanych w środowisku kwasu solnego.
EN
The polyaniline-core-nano-TiO2 composites were prepared by in situ oxidative polymerization of aniline in solutions of two different inorganic acids. The corrosion tests were carried out on carbon steel substrates coated by alkyd coatings (using frame film applicator, one-coat application) containing as the anticorrosion pigments 0.5 mass% of these composites in comparison to coating modified with the same amount of polyaniline composites. The salt spray and EIS (Electrochemical Impedance Spectroscopy) investigations were carried out according to the PN-EN 9227:2012 and PN-EN ISO 16773-2:2008 standards. The EIS test was performed for six weeks, with weekly impedance measurements. The results showed highest anticorrosion resistance of coatings modified with PANI-zinc-oxalate-nano-TiO2 composites, especially the composite obtained in solution of hydrochloric acid.
PL
Spośród około 30 000 obiektów mostowych wchodzących w skład infrastruktury drogowej w Polsce około 8% stanowią obiekty wykonane ze stali. Dominują konstrukcje betonowe, których udział wynosi około 87% [1]. Wśród konstrukcji stalowych znaczną liczbę stanowią obiekty w wieku dochodzącym do 100 lat, występujące jako wiadukty o małej i średniej rozpiętości. Są to obiekty wykonywane jako nitowane, w których ze stali konstruowane są również podpory pośrednie. W artykule przedstawiono analizę stanu technicznego dla jednego z takich obiektów oraz propozycję naprawy i wzmocnienia.
EN
Among 30,000 bridge structures forming the road infrastructure in Poland approximately 8% are made of steel. Concrete structures prevail, with the share of approximately 87% [1]. Structures aged up to 100 years – short and medium span viaducts – account for a significant number among steel structures. They are designed as riveted structures in which also intermediate supports are made of steel. The article presents an analysis of the technical condition of one of such structures as well as the proposal of its repair and reinforcement.
15
Content available Possibilities of pressure die casting of iron alloys
EN
The current trends of production of casts are directed towards production of components disposing of higher accuracy, increased quality of surface and homogenous structure. In case of a thin-walled cast the development of speed of pressing and of pressure was observed inside the mould cavity during pressure die casting of ferrous alloys. In case of die casting of ferrous alloys the attention was paid to life service of a pressing piston and of a filling chamber. The optimal temperature of the steel casting ranges from 1600 to 1750°C and optimal mould temperature ranged from 220 to 260°C. The residues having occurred in gates reached the hardness of 38 HRC and in case of casts the value was of 45 HRC. Influence of acting of resistance pressure on the thinwalled casts only minimally. With the increasing resistance pressure the structure becomes more fine-grained and along with the increasing thickness of the wall the influence of the resistance pressure increases as well. Technology of pressure die casting of iron alloys can be compared with the pressure die casting technology of aluminium alloys. As standard, for pressure die casting the cast irons with carbon content of lower than 3% are recommended.
PL
W artykule poruszono zagadnienia związane ze stosowaniem drogowych barier ochronnych. Bariery są jedną z najczęściej stosowanych metod zapewnienia odpowiedniego poziomu bezpieczeństwa użytkownikom dróg w newralgicznych punktach infrastruktury. Omówiono również kwestie materiałów, z jakich wykonane są bariery stalowe, linowe i betonowe.
EN
The article discusses issues related to the use of traffic barriers. The application of barriers is one of the most common methods of ensuring an adequate level of safety for road users at critical infrastructure points. Materials used for the construction of steel, cable and concrete traffic barriers are also discussed.
17
Content available Accuracy of determined S-N curve by selected models
EN
The study shows models defining the relationship between the fatigue life and the stress amplitude. The first models have been developed at the beginning of the 20th century; however, new models are still being developed. The author decided to compare the most commonly used model, i.e. a linear regression model and the two models discussed in ISO-12107. The comparison also included some recently developed models, i.e. Strohmeyer, Basenaire, Castillo et al., Kohout and Vechet, Leonetti et al., and Pasual and Meeker model, including its modified version. The fatigue data for S355J2+C and AISI 1045 steel were used for the comparison. The best estimate of the fatigue life was obtained by using the modified Pasual and Meeker model.
EN
Methods of obtaining chromium-coated coatings are considered and technology for the formation of boron, silicon and titanium protected layers on steels under conditions of self-propagating high-temperature synthesis is presented. Using the methods of mathematical modeling, when obtaining wear-resistant coatings on machine parts in conditions of self-propagating high-temperature synthesis, optimal compositions of SHS mixtures have been developed. When tested in sliding friction conditions, the best abrasion resistance, among the coatings under consideration, are chromoaluminium-coated coatings. Their wear resistance is 4.8-5 times higher than in uncoated samples, chromoaluminosilicated and chromoalumotated in 2.1-3.5. The gas-transport method of coating with the help of SHS makes it possible to obtain steel 50 and U8A with increased physical and mechanical properties, without requiring high energy costs and time.
EN
Conventional metal manufacturing techniques are suitable for mass production. However, cheaper and faster alternatives are preferred for small batch sizes and individualized components. Directed energy deposition (DED) processes allow depositing metallic material in almost arbitrary shapes. They are characterized by cyclic heat input, hence heating and cooling every point in the workpiece several times. This temperature history leads to distribution of mechanical properties, distortions, residual stresses or even fatigue properties in the part. To avoid experimental trial-and-error optimization, different methods are available to simulate DED processes. Currently, the wire arc additive manufacturing (WAAM) is the most competitive DED process. In this work, a simulation method for the WAAM process is established and validated, which should be capable to calculate global effects (e.g. distortions, residual stresses) of real WAAM-processes with duration of hours and thousands of weld beads. The addition of beads and layers is simulated by the element birth and death technique. The elements are activated according to the movements of the heat source (arc). In this paper, the influence of the time step, the mesh size and the material properties of the inactive elements in hybrid implicit / explicit and fully implicit solutions are evaluated with respect to the computation time and stability. This investigation concludes several recommendations for AM-modelling. For example, a low Young’s modulus (100 N/mm2) for the inactive elements show nearly no influences on the welding simulation, but introduces numerical instabilities in case of multiple welding beads. The Young’s modulus should be increased to 1.000 N/mm2 for small mesh-sizes, small step-sizes and many beads, even when it introduces unwanted stresses.
EN
Purpose: The aim of the proposed research is to investigate the mutual influence of the temperature of an overheated melt and its cooling rate during crystallization on the formation of the cast structure and mechanical properties of structural steels. Design/methodology/approach: Two structural medium-carbon steels were melted in induction furnace and poured from temperatures 1520-1670°C into casting moulds with different heat removal ability. This ensured the crystallization and structure formation of the studied steel castings at cooling rates (Vc) of 5°C/sec (sand-clay mould), 45°C/sec (steel mould), 350°C/sec (water cooled copper mould). It was studied a change of structure formation, mechanical characteristics depending on the temperature-kinetic conditions of the processing of the melt. Based on the processing of the array of obtained experimental data using linear regression analysis and a software package, interpolation models and their graphic images obtained allow a quantitative assessment of the established patterns of structural characteristics and mechanical properties of the studied steels depending on melt temperature (T, °C) and its cooling rate (Vc, °C/sec) during crystallization and structure formation. Findings: Among the technological factors that determine the formation of the cast structure and the mechanical properties of steels, the dominant role is played by the intensity of heat removal during the solidification of castings. The high cooling rate of the melt during crystallization determines an increase in the number of crystallization nuclei due to an increase in the degree of supercooling of the melt, eliminates the negative effect of the high overheating temperature of the metal before casting. Research limitations/implications: In the future, the results can be complemented by studies of the influence of the duration of isothermal exposure of the melt at different temperatures of superheating and cooling conditions. Practical implications: The obtained mathematical models (regression equations) that determine the mutual influence of the cooling rate and the temperature of the melt overheating on the structure and mechanical properties of the studied steels make it possible to obtain steel castings with predetermined properties at the level of properties of wrought steel of similar chemical composition. Originality/value: Interpolation models that allow a quantitative assessment of the established patterns of structural characteristics and mechanical properties of the studied steels depending on the melt temperature (T, °C) and its cooling rate (Vc, °C/sec) during crystallization and structure formation are obtained.
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