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1
Content available remote Dynamiczne metody pomiaru twardości metali i ich stopów
PL
W artykule przedstawiono podstawy pomiarów twardości metali i ich stopów metodami dynamicznymi oraz pokazano obszary zastosowania tych metod. Opisano między innymi skleroskopowe metody pomiarowe Shore’a i Leeba, a także odpowiednie skale twardości. Przeanalizowano zalety i wady poszczególnych metod, zwłaszcza w odniesieniu do zastosowań przemysłowych.
EN
The paper presents the basis for measuring hardness of metals and their alloys using dynamic methods and shows the areas of application of these methods. Among others, Shore and Leeb scleroscopic measuring methods, as well as appropriate hardness scales, have been described. Advantages and disadvantages of individual methods were analyzed, especially in relation to industrial applications.
2
Content available remote Co nowego w branży obróbki cieplnej?
PL
Zmiany w zakresie obróbki cieplnej w ostatnich kilku latach wynikają z ogólnego na rynku dążenia do oszczędności i konkurencyjności. Podobne wizje prezentowane są także na najbliższą przyszłość. Miejmy jedynie nadzieję, że nie dojdzie do sytuacji, która jakiś czas temu dotknęła rynek poligraficzny, gdzie ciągła presja cenowa i wzrastające koszty produkcji spowodowały w krytycznym momencie zerową rentowność produkcji. W takim przypadku już tylko krok dzieli przedsiębiorców od katastrofy, niezależnie od sektora gospodarki. Podobnego scenariusza nie chciałby nikt.
3
Content available remote Model analityczny maksymalnej temperatury wierzchniej strony wióra
PL
Stale szybkotnące pomimo swojej ponad wiekowej tradycji stosowania nadal cieszą się dużym zainteresowaniem. Są one jedynie niewielką częścią ogólnej produkcji materiałów metalowych, lecz nadal stanowią silną pozycję w stosunkowo małej grupie materiałów narzędziowych, ze względu na ich pożądaną ciągliwość.
EN
The values of emissivity coefficients are given for the materials of metal and ceramic coatings. Analytical calculations have been made for the effect of the heating medium (flame) - uncoated wall and then heating medium (flame) - coated wall mutual emissivity coefficients on the values of the exchanged heat flux. Based on the measurement results for the main coating properties, coatings were selected which were the most suitable for spraying the walls of furnaces and heat exchangers, and determined the intensification of heat exchange. These coatings were used to spray the walls of a laboratory waste-heat boiler, and then measurements were taken for the values of the fluxes of heat absorbed by the cooling water flowing in the boiler tubes covered with different type coatings. The analytical calculations and the laboratory tests have been confirmed by the results of full-scale operation on the elements of metallurgical equipment.
PL
Przytoczono wartości współczynników emisyjności materiałów metalowych i ceramicznych oraz powłok. Dokonano analitycznych obliczeń wpływu współczynnika emisyjności wzajemnej: czynnik nagrzewający (płomień) - ściana bez powłok, a następnie czynnik nagrzewający (płomień) ściana z powłoką (czynnik nagrzewany) na wartości strumienia wymienianego ciepła. W oparciu o wyniki pomiarów podstawowych własności powłok wytypowano najbardziej przydatne do natryskiwania ścian pieców i wymienników warunkujące intensyfikację wymiany ciepła. Powłokami tymi natryskano ściany laboratoryjnego kotła odzysknicowego i dokonano pomiarów wartości strumienia ciepła przejmowanego przez wodę chłodzącą - przepływającą w rurach kotła pokrytych różnymi rodzajami powłok. Obliczenia analityczne i badania laboratoryjne potwierdzono wynikami eksploatacji przemysłowej w elementach urządzeń hutniczych.
PL
W pracy przedstawiono rezultaty badań zmęczeniowych próbek ze stopu aluminium 2017-T4(A) oraz stali stopowych S355J2WP i S355J0 w warunkach stałoamplitudowych proporcjonalnych kombinacji zginania ze skręcaniem z uwzględnieniem wartości średniej naprężenia. Wyniki badań eksperymentalnych porównano z wynikami obliczeń z wykorzystaniem modeli Goodmana, Gerbera i Morrowa oraz modelu energetycznego. W przypadku metod obliczeń opartych na naprężeniach, wieloosiowy stan naprężenia redukowano do jednoosiowego, wykorzystując zależność Hubera-Misesa. W przypadku metody energetycznej, wieloosiowy stan naprężenia redukowano do jednoosiowego, stosując parametr naprężeniowo-odkształceniowy w płaszczyźnie krytycznej.
EN
The paper contains the results of fatigue tests of specimens made of the aluminium alloy 2017-T4(A) and S355J2WP and S355JO alloy steels under constant amplitudę proportional combined bending with torsion including stress mean values. Results of tests were compared with the calculated data using the models by Goodman, Gerber and Morrow, and the stress-strain parameter (Was). In the case of calculations based on stresses, the multiaxial stress state was reduced to the uniaxial one, using the Huber-Mises relationship. In the case of energy method, the multiaxial stress state was reduced to the uniaxial one with the stress-strain parameter on the critical piane.
PL
W wyniku realizacji projektów badawczych rozwojowych, projektów celowych, prac własnych dofinansowanych ze środków budżetowych oraz prac zleconych przez zakłady przemysłu obronnego, Instytut Metalurgii Żelaza (IMŻ) we współpracy z Politechniką Poznańską, wojskowymi instytutami badawczymi i wytwórcami rozwijanych wyrobów opracował nowoczesne materiały konstrukcyjne na elementy uzbrojenia. Opracowano również technologie wytwarzania wyrobów z tych materiałów, które znalazły zastosowanie m.in. w produkcji do amunicji okuć 120mm, korpusów silników rakietowych kalibru od 70 do 300mm, pierścieni wiodących do pocisków kalibru 35mm i skorup HE (high explosive). Obecnie rozpoczęto projekt mający na celu opracowanie supertwardych materiałów na bazie stopów żelaza z przeznaczeniem na pancerze. W celu zapewnienia dostaw specjalnych materiałów metalowych do zastosowań w przemyśle obronnym, przedstawiono koncepcję uruchomienia centrum produkcji i rozwoju metalowych materiałów konstrukcyjnych.
EN
As a result of research and development projects, targeted projects, own projects subsidized with the domestic budget funds and research commissioned by defense industry plants, Institute for Ferrous Metallurgy in cooperation with Poznań University of Technology, military scientific institutes and manufacturers of the developed new products has worked out modern structural materials for elements of armament. Technologies for production of armament parts made from the new materials have been worked out. They are applied, among others, in production of 120mm cartridge cases, engine bodies of 70-300mm caliber rocket projectiles, leading rings for 35mm caliber missiles and HE (high explosives) shell cases. Currently a new project has been started. Its aim is to work out superhard materials on the basis of iron alloys dedicated for armour. In order to ensure supplies of special metallic materials used in defense industry, an idea of establishing centre for production and development of structural metallic materials was presented.
8
Content available remote Effect of high temperature deformation on the structure of Ni based superalloy
EN
Purpose: A study on the hot deformation behaviour and dynamic structural processes (dynamic precipitation operating during deformation at elevated temperatures) of nickel based superalloy was presented. Design/methodology/approach: Compression tests were carried out on precipitations hardenable nickel based superalloy of Inconel 718 at constant true strain rates of 10-4, 4x10-4s-1 within a temperature range of 720-1150° C. True stress-true strain curves and microstructure analysis of hot deformed alloy were described. Microstructure examination has been carried out on the compressed samples of Inconel 718 alloy using an optical microscope - Nikon 300 and in the scanning electron microscope HITACHI S-3400 (SEM) in a conventional back-scattered electron mode on polished sections etched with Marble's solution. Findings: Structural observations of deformed at high temperatures, previously solution treated Inconel alloy revealed non uniform deformation effects. Distribution of molybdenum-rich carbides was found to be affected by localized flow within the investigated strain range at relatively low deformation temperatures 720 - 850° C. Microstructural examination of the alloy also shown that shear banding, cavities growth and intergranular cracks penetrating through the whole grains were responsible for decrease in the flow stress at temperature of 720, 800 and 850° C and a specimen fracture at larger strains. On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (σ pl -T and σ pl - ) and compression data were used to determine material's constants. These constants allowed to derive a formula that describes the relationship between strain rate (ε), deformation temperature (T) and flow stress σ pl. Research limitations/implications: Even though, the light optical microstructure observation of deformed samples revealed some effects of heterogeneous distribution of the phase components, in order to complete and confirm obtained results it is recommended to perform further analysis of the alloy by using transmission electron microscopy technique (TEM). Practical implications: Interaction of precipitation process developed during deformation below solvus temperature and heterogenuos deformation (flow localization) can become a significant aspect of high temperature performance of precipitation hardenable alloys and may perhaps also allow produce specific microstructures of such deformed materials. Originality/value: It is a scarcity of data which are to describe specific features of phase transformation processes in precipitation hardenable alloys. In addition, existing data do not allow to simplify structural features of dynamic precipitation and simplifying structural description of the process. The compression tests on age hardenable alloys and the analysis of dynamic precipitation process have got a practical meaning.
9
Content available remote Corrosion behaviour of metallic biomaterials used as orthodontic wires
EN
Purpose: The aim of the work was evaluation of the corrosion resistance of the commercial metallic orthodontic wires from different manufacturers in simulated intra-oral environment. Design/methodology/approach: Corrosion resistance tests were carried out in artificial saliva at the temperature 37 ± 1° C with the use of the VoltaLab ® PGP 201 system for electrochemical tests. The saturated calomel electrode (SCE) was applied as the reference electrode and the auxiliary electrode was a platinum foil. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with the use of the potentiodynamic method. In order to evaluate crevice corrosion resistance the samples were polarized in the potential equal to 0.8 V by 900 seconds. Findings: Results of corrosion resistance tests of the CrNi, NiTi and CuNiTi wires showed comparable data of parameters obtained in the artificial saliva. Research limitations/implications: The obtained results show the influence of artificial saliva on the electrochemical corrosion of orthodontic wires. In order to demonstrate the higher risk of corrosion, which can have two consequences: a loss of the physical properties and the release of Ni ions (which have been shown to be toxic and the cause of allergic reactions) - additional research on fatigue corrosion should be carried out. Originality/value: The analysis of the obtained results show that that commonly used materials for making orthodontic wires (because of their interesting properties - elasticity and shape memory) can be used in different orthodontic treatment stages to correct numerous clinical conditions. The most favorable characteristics were observed for the new NiTi samples (American Orthodontics).
11
Content available remote Corrosion behaviour of Co-Cr-W-Ni alloy in diverse body fluids
EN
Purpose: The aim of the work was evaluation of corrosion resistance of implantable Co-Cr-W-Ni alloy in simulated body fluids: human blood (artificial plasma), urine (artificial urine) and bone tissue (Tyrode solution). Design/methodology/approach: Corrosion resistance tests were carried out in the selected physiological body fluids at the temperature 37 ± 1°C with the use of the VoltaLab PGP 201 system for electrochemical tests. The saturated calomel electrode (SCE) was applied as the reference electrode and the auxiliary electrode was a platinum foil. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with the use of the potentiodynamic method. In order to evaluate crevice corrosion resistance the samples were polarized in the potential equal to 0,8 V by 900 seconds. Roughness of all the samples was evaluated with the use of the SURTRONIC 3+(Taylor/Hobson) surface analyzer. Findings: Results of corrosion resistance tests of the Co-Cr-W-Ni alloy showed the diverse values of parameters obtained in the individual solutions. The suggested surface treatments ensure good crevice corrosion resistance of the Co-Cr-W-Ni alloy in all the tested physiological fluids. Research limitations/implications: The obtained results show the necessity of selection of the appropriate physiological solution, reflecting the specificity of body environment. In order to fully characterize the material in the human body environment, additional research on stress and fatigue corrosion should be carried out. Originality/value: The analysis of the obtained results show favorable influence of the suggested surface treatment of the Co-Cr-W-Ni alloy. Regardless of the selected physiological solution, the most favorable characteristics was observed for the electropolished and passivated samples.
EN
The paper is concerned both with mathematical engineering and material engineering. Mathematical methods are applied as well as methods for calculating thermodynamic properties of pure substances generally, in particular those of pure gold. New procedures are suggested for calculating the enthalpy, entropy, and Gibbs free energy from the values of isobaric olar thermal capacity. The methods employed are based on non-linear regression analysis, splines and modification of the composite Simpson quadrature formula. The results are considerably accurate and flexible in expresssing the experimental data.
EN
The paper deals with non-traditional applications of the theory of fuzzy sets to expressing the properties of materials with numeric data of a vague character. The theoretical part is concerned with the development of the fuzzy logic and fuzzy searching in fuzzy sets with a polygonal membership function. These methods have been used to adopt a new approach to the solution of a relational database system. The results will be applied to the creation of a fuzzy database system as part of an upgrade of the classic database system Mexpert 2.0 for metal materials.
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