1956 KB37 KB199920252015Campillo, BernardoLópez-Martínez, EdgarSerna, SergioVergara-Hernández, Héctor Javierštevilka:12letnik:61str. 741-750, SI 133ISSN:0039-2480COBISSID:14411035URN:URN:NBN:SI:doc-KP9GGHPZenZveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikmikrolegirano jeklospecifična toplotatoplotna prevodnosttoplotno vplivano področjeumetne nevronske mreževarjenjeArtificial neural networks to estimate the thermal properties of an experimental micro-alloyed steel and their application to the welding thermal analysis|The effect of welding thermal cycles on the microstructure and micro-hardness of the heat-affected zone (HAZ) of an experimental micro- alloyed steel was studied. Due to the experimental difficulties involved in acquiring the thermal cycles, these were determined by applying the solutions of Rosenthal's equations for thick and thin plates. However, to perform this thermal analysis, it requires knowledge of the thermal properties of the micro-alloyed steel; therefore, the implementation of two artificial neural networks (ANNs) was proposed as tool to estimate the thermal conductivity and the heat capacity as a function of the chemical composition and temperature. The ANNs were trained with information obtained from the literature review and then tested with steels that were not used for the training step, but with thermal properties known. A good approximation between the actual and the estimated properties was observed. It was determined that the microstructural characteristics of the welding zone are a function of the thermal cycles, although there is no great difference in micro-hardness. Martensite was not observed in the welding zone; therefore, the welds of this steel, under these welding conditions, could not be susceptible to hydrogen induced cracking (HIC)Izdelava jeklenih metalurških komponent zahteva poznavanje toplotnih lastnosti v funkciji temperature. Pri procesih, kot sta varjenje in toplotna obdelava jekel, je nujno poznavanje toplotne prevodnosti in specifične toplote za snovanje, simulacijo in izbiro ciklov segrevanja in ohlajevanja, od katerih bo odvisna mikrostruktura in posledično mehanske lastnosti materiala. Namen predstavljene študije je ocenitev teh toplotnih lastnosti in njihova uporaba pri toplotni analizi toplotno vplivanega področja pri varjenju eksperimentalnega mikrolegiranega jekla. Toplotna analiza varjenja vključuje določanje dejanskih toplotnih ciklov. Zaradi težav, ki se pojavljajo pri eksperimentalnem določanju teh ciklov, pa so bili le-ti opredeljeni z uporabo utežnih faktorjev na Rosenthalovih analitičnih rešitvah. Ker smo delali z eksperimentalnim jeklom, toplotne lastnosti niso znane. Umetne nevronske mreže (ANN) so se izkazale za zmogljivo orodje za napovedovanje parametrov ter simulacijo in odpravljanje težav pri tehniških aplikacijah, zato je bila sprejeta odločitev, da bosta za oceno omenjenih toplotnih lastnosti zasnovani dve ANNTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo