Bányászati és Kohászati Lapok - Kohászat, 2013 (146. évfolyam, 1-6. szám)
2013 / 1. szám
TARTALOM Vaskohászat KB Májlinger K. - Szabó P. J.: Ausztenites acél keményforrasztáskor fellépő szemcsehatármenti repedése HE Tardy P.: Az acélhulladék keletkezése és felhasználása: változó arányok KB Topitzer Jánosra emlékeztek és a szerszámacélgyártás fejlődését tekintették át Öntészet KE Diaconu, V.-L. - Sjögren, T. - Skoglund, P. - Diószegi A.: A molibdén hatása az öntöttvasak termomechanikus hőfárasztási tulajdonságaira KE Korszerű mintakészítés - szakmai nap az M+M Kft.-nél KE MÖSZ-hírek Fémkohászat ШИ Tranta F.: Öntött AlMnMg (3004) alumíniumötvözet vizsgálata a villamos ellenállás és a termoerö együttes mérésével Ki Kovács S. - Mertinger V.: Huzalhúzási paraméterek komplex optimalizáló eljárásainak összehasonlítása KB Beszámoló a XIII. Fémkohászati Szakmai Napról Anyagtudomány KE Kundrák J. - Gyáni K. - Pálmai Z.: A felszíni réteg vizsgálata keményesztergált belső hengeres felületeken KE Barkóczy P. - Gyöngyösi Sz. - Geiger J,: Fázisátalakulások során végbemenő csíraképződés dinamikájának szimulációja sejtautomata módszerrel Felsőoktatás KE Az MTA Metallurgiai Bizottsága a kohómérnökképzés helyzetéről tanácskozott KE Tanulmányút a brnoi FOND-EX Nemzetközi Kiállítás és Vásáron KE Egyetemi hírek Hírmondó KE NÉVJEGY - Szablyár Péter ■И Acélipari témák a Tudomány Hetén a Borovszky-év jegyében Ш Szent Hubertus- és Szent Borbála-emlékest Solton ■ai Nekrológok A kiadvány a FÉMALK Zrt. támogatásával jelenik meg Öntészet rovatunkat az 1950- ben indított és 1991-ben megszűnt önálló szaklap, a BKL Öntöde utódjának tekintjük. FROM THE CONTENT Májlinger, K. - Szabó, P. J.: Intercrystalline Cracking of Austenitic Steel during Brazing..........................................................1 During brazing of austenitic stainless steel with copper based brazing material a common failure occurs, namely that the brazing material solutes along grain boundaries, which look like cracks. This unfortunate effect occurred when both AISI 304 and AISI 310 steel was brazed. To avoid this unwanted effect - since the cracks propagate mainly on high angle grain boundaries - our goal was to enhance the fraction of special coincident site lattice type grain boundaries with thermomechanical treatment. Experiments were performed for 1, 48 and 72 hour heat treatments at 650 °C after different levels of cold rolling. The brazing was made with Boehler SG-CuSi3 brazing material. The grain boundaries were investigated on electrolitically polished samples in an electron microscope with electron backscattered diffraction technique. Due to the thermomechanical treatment the fraction of CSL grain boundaries were increased and significant decrease in the crack size was found in depth and width, respectively. In our present work the effect of different treatment parameters was investigated. Tardy, P.: Demand and arising of ferrous scrap: changing balance..........................6 Security of scrap supply depends on the equilibrium of its demand and arising. To analyse this relation a model has been worked out and used for the calculation of the evolution of the two amounts globally and for some selected regions till 2017. Arising could hardly cover demand before the outbrake of the global financial and economic crisis in 2008, but after that market strains were eased. If steelmaking practice will not change, arising will grow faster than demand and even China may be self-sufficient. Diaconu, V.-L. - Sjögren, T. - Skoglund, P. - Diószegi, A.: The molybdenum effect onto the thermomechanical fatigue properties of cast iron...............................13 The goal of the experiments is to investigate the thermomechanical fatigue properties of compacted and gray cast irons alloyed with molybdenum and their comparison. For this purpose were casted four types of compacted graphite irons having different molybdenum content and one gray cast iron which properties are closed to the GJL 300 type. The measurements were performed on specimens machined from these types of cast iron. At the same times investigations were done on specimens machined from cylinders of different diameter in order to detect the relationship between different cooling rates and solidification. In all cases the results showed the correlation between molybdenum content and the thermomechanical properties of compacted graphite iron. Tranta, F.: Investigation of solidified AlMnMg alloy (3004 type) using simultaneous measurement of electric resistance and thermoforce........................................22 The concentration of manganese and magnesium in solid solution was determined after the homogeneization heat treatment using simultaneous measurement of electric resistance and thermoforce by applying the functions of Nordheim-Gorter and the Mattheisen-rules in case of semi continuous casting AlMnMg alloy. The concentration of magnesium slightly changed during the heat treatment, whereas the manganese precipitates from the supersaturated solidified structure below 600 °C, and above 600 °C it solved. Kovács, S. - Mertinger, V: Comparison of complex optimizing processes of parameters of wire drawing....................................27 In this paper, the algorithmic realization of complex optimization objective functions of parameters of multi-step wire cold drawing technology is described. As a result of the two-types of optimization, identical optimum cone-angles can be obtained in each pass and on the other hand optimum cone angles having optional size in each pass can be obtained. The calculation time of objective functions as one of the most important factors of non-linear optimization was investigated. The optimum technological parameters obtained by using the two types of objective functions were compared and it was defined why it is worth using the complex optimization having a shorter calculation time. Kundrák, J. - Gyáni, К. - Pálmai, Z.: Investigation of the surface layer on hard turned inner cylindrical surfaces............... 33 In hard turning having been applied wider and wider, occasionally a so called white layer appears on the machined surface, which is mostly harmful. The formation of the white layer appearing on the inner cylindrical surface of gear wheels made of case hardened steel 20MnCr5 has been studied in different versions of cutting technology. Depending on them, the thickness of the white layer was found different. Based on picture analysing and x-ray diffraction examinations it is stated that this white layer mainly consists of martensit besides which 5...25% residual austenite can be found. Barkóczy, P. - Gyöngyösi, Sz. - Geiger, J.: Simulation of the dynamics of nucleation in phase trasformation by cellular automata ....................................................................39 The dendritic growth is efficiently studied by a diffusion limited aggregation cellular automaton. The main problems of these automata are that cannot show a correct way the process of long range diffusion, and cannot produce the dynamics of nucleation. In this article an automaton is introduced which able to simulate the mentioned processes in correct way. For this a random walk based automaton is used with an extended neighborhood. This neighborhood orders the particles to nuclei. • Szerkesztőség: 1051 Budapest, Október 6. utca 7., III. em. • Telefon: 06-1-201-7337 • • Levélcím: 1371 Budapest, Pf. 433, e-mail: bkl.kohaszat@gmail.com • • Felelős szerkesztő: Balázs Tamás • • A szerkesztőség tagjai: dr. Buzáné dr. Dénes Margit, dr. Klug Ottó, dr. Kórodi István, Lengyelné Kiss Katalin, Schudich Anna, Szende György, dr. Takács István, dr. Tardy Pál, dr. Török Tamás • • Kiadó: Országos Magyar Bányászati és Kohászati Egyesület • Felelős kiadó: dr. 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