Formation of Medium Carbon TRIP Steel Microstructure During Annealing in the Intercritical Temperature Range

• Autorzy: Kokosza A. , Pacyna J.

Identyfikatory

DOI

10.2478/amm-2014-0170

Warianty tytułu

PL

Kształtowanie mikrostruktury średniowęglowej stali typu TRIP podczas wyżarzania w zakresie temperatur krytycznych

• Języki publikacji: EN

Abstrakty

EN

The paper presents the results of research conducted on austenite formation in the microstructure of 41MnSi6-5 TRIP steel during annealing in the intercritical temperature range. The influence of the annealing temperature on the volume fraction of retained austenite in the microstructure of the investigated steel after water quenching was also determined. Based on the results of a dilatometric analysis and metallographic investigation it was noted that the pearlite-to-austenite transformation does not occur at a constant temperature, which is referred to as Ac₁, but rather within some, possible to determine, temperature range which is bounded by the values Ac_1s and Ac_1f. Moreover, through X-ray analysis, it was stated that the largest amount of retained austenite remained in the samples which were annealed at the lowest temperatures in the Ac_1s and Ac_1f range prior to quenching. Increasing the annealing temperature to a two-phase a+g (ferrite + austenite) range, resulted in a decrease of the volume fraction of retained austenite. It was also found that during annealing in Ac_1s and Ac_1f temperature range, austenite is also formed from ferrite simultaneously. This could be the reason for the decrease the carbon content in the formed austenite and consequently the decrease in the volume fraction of retained austenite in the microstructure of the investigated steel, which was quenched after having reached temperatures higher than Ac_1s + 30°C.

PL

W pracy przedstawiono wyniki badań nad tworzeniem się austenitu w mikrostrukturze stali 41MnSi6-5 typu TRIP podczas wyżarzania w zakresie temperatur krytycznych. Określono również wpływ temperatury takiego wyżarzania na udział objętościowy austenitu szczątkowego, jaki pozostaje w mikrostrukturze badanej stali po zahartowaniu od takich temperatur. Na podstawie wyników analizy dylatometrycznej oraz badań metalograficznych stwierdzono, że w badanej stali przemiana perlit – austenit nie przebiega w stałej temperaturze określanej jako Ac_1s lecz w pewnym, możliwym do określenia jej zakresie, którego granice wyznaczają wartości Ac_1s and Ac_1f. Ponadto, metodą analizy rentgenowskiej wykazano, że najwięcej austenitu szczątkowego pozostawało w tych próbkach z badanej stali, które przed zahartowaniem były wyżarzane przy najniższej temperaturze z zakresu Ac_1s and Ac_1f. Podwyższenie temperatury wyżarzania do zakresu dwufazowego a+g (ferryt+ austenit) było przyczyną zmniejszenia udziału austenitu szczątkowego. Stwierdzono, że podczas wyżarzania w zakresie temperatur Ac_1s and Ac_1f tworzy się również z ferrytu. Mogło to być przyczyną zmniejszenia zawartości węgla w tworzącym się austenicie i spadku udziału austenitu szczątkowego w mikrostrukturze badanej stali po jej zahartowaniu od temperatur wyższych od Ac_1s + 30°C.

Słowa kluczowe

EN

phase transformation; critical temperatures; retained austenite; TRIP steels

PL

przemiany fazowe; temperatury krytyczne; austenit szczątkowy; stale TRIP

• Wydawca: Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences
• Czasopismo: Archives of Metallurgy and Materials
• Rocznik: 2014
• Tom: Vol. 59, iss. 3
• Strony: 1017--1022
• Opis fizyczny: Bibliogr. 22 poz., rys., tab.

Twórcy

autor

Kokosza A.

• AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków, Poland

autor

Pacyna J.

• AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków, Poland

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