MATERIALS ENGINEERING, Vol. 17, 2010, No. 3
published on December 2010
CONTENTS and ABSTRACTS
Tan, W., Stoschka, F., Maderbacher, H., Riedler, M., Eichlseder, W., Romagnoli, F. (pp. 1-8)
INVESTIGATIONS TO IMPROVE THE TRANSFERABILITY OF SPECIMEN RESULTS BY REAL COMPONENT Full text (PDF 1444 kB)
For the improvement of the lifetime calculation of components made of the titanium alloy Ti-6-4, a closed loop methodology from specimen to the component is presented. Based on forged pre-material specimens fatigue tests are done as a basic research, which are presented as S/N-curves. With the determined material data a lifetime calculation with the program FEMFAT is done on a typically fitting element. Finally the results of the lifetime calculation are compared to real component tests, which are done to evaluate the results of the lifetime calculation. The component tests are performed with constant and variable load. Therewith the transferability of specimen results to real components is shown. Additional fracture analysis by light microscope and scanning electron microscope is carried out to give further information of the influence factor of the lifetime and a further description between fracture behaviour of specimen and components.
Ganev, N., Pala, Z., Kolařík, K. (pp. 9-14)
THE IMPACT OF CUTTING CONDITIONS ON RESIDUAL STRESSES IN THE CASE OF PLAIN MILLING Full text (PDF 251 kB)
The goal of the contribution is to present results of X-ray diffraction study of residual stresses in the surface layers of guide gibs for machining centres made from hardened 14 100.3 steel. Investigated samples were side-milled using a cutter head with tool tips. While the cutting depth was kept constant, various cutting speeds, and feeds were applied. Surface integrity was studied in order to assess the effect of the varied machining parameters on both the surface and depth distributions of residual stresses. The state of residual stresses was determined in two azimuths by means of X-ray diffraction technique. Considering that the penetration depth of CrK???X-ray radiation in steels is less than 5 µm, electrochemical etching was applied for depth profiling.
Bubenko, L., Konečná, R., Nicoletto, G. (pp. 15-20)
FATIGUE CRACK PROPAGATION THROUGH AUSTEMPERED DUCTILE IRON MICROSTRUCTURE Full text (PDF 572 kB)
Austempered ductile iron (ADI) has a wide range of application, particularly for castings used in automotive and earth moving machinery industries. These components are usually subjected to variable dynamic loading that may promote initiation and propagation of fatigue cracks up to final fracture. Thus, it is important to determine the fatigue crack propagation behavior of ADI. Since fatigue crack growth rate (da/dN) vs. stress intensity factor K data describe fatigue crack propagation resistance and fatigue durability of structural materials, da/dN vs. Ka curves of ADI 1050 are reported here. The threshold amplitude of stress intensity factor Kath is also determined. Finally, the influence of stress intensity factor amplitude to the character of fatigue crack propagation through the ADI microstructure is described.
Fajnor, P., Liptáková, T., Konstantová, V. (pp. 21-27)
INFLUENCE OF AISI 316Ti STAINLESS STELL SURFACE TREATMENT ON PITTING CORROSION IN VARIOUS SOLUTIONS Full text (PDF 531 kB)
Investigation of the surface treatment effect on the resistance of AISI 316Ti stainless steel to pitting corrosion is presented in this paper. The grinded surfaces without additional chemical treatment, grinded and pickled, grinded, pickled and passivated surfaces are tested. The corrosion tests are carried out by exposition in solution which evoke pitting and by electrochemical cyclic potential - sweep method. According to the results the surface treatment has a great influence on the resistance of the tested material to pitting. It is not possible to estimate the best surface treatment because behavior of AISI 316Ti stainless steel with different surface state depends on the mechanism of corrosion processes which vary in the used experimental methods.
Liptáková, T., Malcho, M., Jandačka, J. (pp. 28-34)
CORROSION BEHAVIOUR OF CHOSEN CONSTRUCTION METALS IN THE DUCT SYSTEM OF THE RECYCLING ALUMINIUM FURNACE Full text (PDF 1214 kB)
The corrosion behaviour of five types of steels and cast irons proposed for production of the duct system in the recycling aluminium furnace is studied in this article. The metals tested were exposed in the real conditions at high temperature (from 800 to 1100°C ) in very aggressive environment of combustion products for thirty days. The character and intensity of corrosion attack of the tested materials are evaluated by gravimetric and metallographic analysis.
© University of Žilina, Faculty of Mechanical Engineering, ISSN 1335-0803