21 KB337 KB17 KB200020262013Hauserova, DanielaJirkova, HanaKucerova, LudmilaMasek, Bohuslavštevilka:3letnik:47str. 335-339ISSN:1580-2949COBISSID:999338URN:URN:NBN:SI:doc-V2DJULMCenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijedeformacijemaloogljično jekloperlitžarjenjeEnergy- and time-saving low-temperature thermomechanical treatment of low-carbon plain steel| Prihranki energije in časa pri nizkotemperaturni termomehanski obdelavi maloogljičnega ploščatega jekla|Reduction of energy is one way of cutting the cost of finished steel products. In this context heat treatment is a costly stage of the production. This paper presents a method of reducing soft-annealing times. The method termed as ASR (accelerated spheroidization and refinement) was employed for improving the cold formability of the ferrite-pearlite steel. In this study, plain low-carbon RSt-32 steel was used as the experimental material. The influence of deformation below the Asub{c1} temperature on grain refinement and carbide spheroidization, as well the influence of the temperature cycling around the Asub{c1} temperature within the temperature intervals of various widths were explored. In addition, attention was paid to the effects of the holding time between deformation steps and to the amount of deformation heat. The initial lamellar pearlite was converted into a recrystallized structure with fine ferrite grains of about 3 mum and fine spheroidized cementite. The final hardness was about 150 HV10. This is by about 25 % lower than the hardness of the initial ferrite-lamellar pearlite structure. Significant time and energy savings can be reached as the treatment shortens the thermomechanical exposurefrom several hours to several minutesZmanjševanje porabe energije je ena od poti za zmanjšanje stroškov končnih jeklenih proizvodov. V tem kontekstu je toplotna obdelava draga faza proizvodnje. Članek predstavlja metodo za zmanjšanje časa mehkega žarjenja. Metoda, označena z ASR (pospešena sferoidizacija in zmanjšanje zrn) je bila uporabljena za izboljšanje hladne preoblikovalnosti feritno-perlitnega jekla. Za eksperimentalni material v tej študiji je bilo uporabljeno maloogljično jeklo RSt-32. Preiskan je bil vpliv deformacije pod temperaturo Aspodaj{c1} na zmanjšanje velikosti zrn in na sferoidizacijo karbida, kot tudi vpliv nihanja temperature okrog Aspodaj{c1} v različno širokih temperaturnih intervalih. Dodatna pozornost je bila posvečena še učinku časa zadržanja med posameznimi deformacijami in na delež deformacijske toplote. Začetni lamelarni perlit se je pretvoril v rekristalizirano strukturo z drobnimi zrni ferita, velikosti okrog 3 mim in drobno sferoidiziranim cementitom. Končna trdota je bila okrog 150 HV10. To je okrog 25 % nižje od trdote začetne strukture s feritom in lamelarnim perlitom. Mogoče je doseči pomembne prihranke v času in energiji, saj termomehanska obdelava skrajša potreben čas od nekaj ur na nekaj minutTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije