Abstract
In contrast to quenching and tempering (Q&T), with quenching to room temperature, quenching and partitioning (Q&P) usually applies quenching to a temperature between Ms and room temperature. To stabilize a sufficient amount of retained austenite (RA), carbon diffusion from martensite into austenite and a prevention of cementite formation takes place during the successive partitioning step. Larger amount of RA, and its transformation into martensite during plastic deformation, provides Q&P treated steels with an enhanced combination of strength and ductility. In this investigation, the effect of different Q&T and Q&P treatments on the hardness-toughness relationship was determined. These results are compared with the RA contents and mechanical properties provided by tensile testing. The obtained results clearly demonstrate that the optimum parameters for strength and ductility do not match with the best combinations of hardness and toughness. Furthermore, the stability of the RA plays an important role in the understanding of toughness properties of the investigated Q&P steels.
Kurzfassung
Im Gegensatz zum Vergüten (Abschrecken und Anlassen, Q&T), bei dem auf Raumtemperatur abgeschreckt wird, wird beim Abschrecken und Umverteilen (Q&P) normalerweise auf eine Temperatur zwischen Ms und Raumtemperatur abgeschreckt. Um eine ausreichende Menge an Restaustenit (RA) zu stabilisieren, findet während des anschließenden Anlassens eine Kohlenstoffdiffusion von Martensit in Austenit statt und die Bildung von Zementit wird verhindert. Eine größere Menge an RA und seine Umwandlung in Martensit während der plastischen Verformung verleihen den Q&P-behandelten Stählen eine bessere Kombination aus Festigkeit und Duktilität. In dieser Untersuchung wurde die Auswirkung verschiedener Q&T- und Q&P-Behandlungen auf das Verhältnis zwischen Härte und Zähigkeit bestimmt. Diese Ergebnisse werden mit dem RA-Gehalt und den mechanischen Eigenschaften verglichen, die durch Zugversuche ermittelt wurden. Die erzielten Ergebnisse zeigen deutlich, dass die optimalen Parameter für Festigkeit und Duktilität nicht mit den besten Kombinationen von Härte und Zähigkeit übereinstimmen. Darüber hinaus spielt die Stabilität des RA eine wichtige Rolle für das Verständnis der Zähigkeitseigenschaften der untersuchten Q&P-Stähle.
Acknowledgement
The authors sincerely acknowledge the support of the Austrian Research Promotion Agency (FFG) related to the frontrunner project No. 860188 “Upscaling of medium Mn-TRIP steels”
Danksagung
Die Autoren bedanken sich herzlich für die Unterstützung durch die Österreichische Forschungsförderungsgesellschaft (FFG) im Rahmen des Frontrunner-Projekts Nr. 860188 „Upscaling of medium Mn-TRIP steels“.
References
1 Matlock, D. K.; Speer, J. G.; De More, E.; Gibbs, P. J.: Recent developments in advanced high strength sheet steels for automotive applications: An overview. JESTECH 15 (2012) 1, pp. 1‒12Search in Google Scholar
2 Spenger, F.; Hebesberger, T.; Pichler, A.; Krempaszky, C.; Werner, E. A.: AHSS steel grades: Strain hardening and damage as material design criteria. Proc. Int. Conf. on New Developments in Advanced High Strength Sheet Steels, 15.-18.06.08, Orlando, USA, Assoc. Iron & Steel Technol., Warrendale, USA, 2008, pp. 39‒49. – ISBN: 9781886362994Search in Google Scholar
3 Taylor, T.: Novel cold-rolled martensitic ultra-high-strength steels for roll forming technologies. Mater. Sci Tech. 32 (2016) 16, pp. 1730‒1741, DOI:10.1080/0267083 6.2016.114684010.1080/02670836.2016.1146840Search in Google Scholar
4 Speer, J. G.; Streicher, A. M.; Matlock, D. K.; Rizzo, F.; Krauss, G.: Quenching and partitioning: A fundamentally new process to create high strength TRIP sheet microstructures. Proc. Int. Conf. Austenite formation and decomposition, 09.-12.11.03, Chicago, USA, Iron & Steel Society, Warrendale, USA, 2003, pp. 505‒522Search in Google Scholar
5 Speer, J. G.; Rizzo, F. C.; Matlock, D. K.; Edmonds, D. V.: The „quenching and partitioning“ process: Background and recent progress. Mater. Res. 8 (2005) 4, pp. 417‒423, DOI:10.1590/s1516-1439200500040001010.1590/s1516-14392005000400010Search in Google Scholar
6 Speer, J.; Matlock, D. K.; De Cooman, B. C.; Schroth, J. G.: Carbon partitioning into austenite after martensite transformation. Acta Mater 51 (2003) 9, pp. 2611‒2622, DOI:10.1016/s1359-6454(03)00059-410.1016/s1359-6454(03)00059-4Search in Google Scholar
7 De Moor, E.; Lacroix, S.; Clarke, A. J.; Penning, J.; Speer, J. G.: Effect of retained austenite stabilized via quench and partitioning on the strain hardening of martensitic steels. Metall. Mater. Trans. A 39 (2008) 11, pp. 2586‒2595, DOI:10.1007/ S11661-008-9609-z10.1007/S11661-008-9609-zSearch in Google Scholar
8 Seo, E. J.; Cho, L.; Estrin, Y.; De Cooman, B. C.: Microstructure-mechanical properties relationships for quenching and partitioning (Q&P) processed steel. Acta Mater. 113 (2016), pp. 124‒139, DOI:10.1016/j.actamat.2016.04.04810.1016/j.actamat.2016.04.048Search in Google Scholar
9 Stewart, R. A.; Speer, J. G.; Thomas, B. G.; De Moor, E.; Clarke, A. J.: Quenching and partitioning of plate steels: Partitioning design methodology. Metall. Mater. Trans. A 50 (2019) 10, pp. 4701‒4713, DOI:10.1007/s11661-019-05337-310.1007/s11661-019-05337-3Search in Google Scholar
10 Thomas, G. A.; Speer, J. G.; Matlock, D. K.: Quenched and partitioned microstructures produced via gleeble simulations of hot-strip mill cooling practices. Metall. Mater. Trans. A 42 (2011) 12, pp. 3652‒3659, DOI:10.1007/s11661-011-0648-510.1007/s11661-011-0648-5Search in Google Scholar
11 Große-Heilmann, N.; Peters, A.: Materials concepts for high strength and ultra high strength automotive applications. Proc. 3rd Int. Conf. on Steels in Cars and Trucks, 05.-09.06.11, Salzburg, Austria, H. J. Wieland, TEMA (eds.), Stahleisen, Aachen, pp. 255‒262. – ISBN: 978-3514007833Search in Google Scholar
12 Speich, G. R.; Leslie, W. C.: Tempering of steel. Metall. Trans. 3 (1972), pp. 1043‒105410.1007/BF02642436Search in Google Scholar
13 Rademacher, L.: Anlassen von Martensit und Bainit. Vergütung oder Verspröden? – Teil 1: Praktische Beispiele für die Gebrauchseigenschaften. Härterei-Techn. Mitt. 33 (1978) 5, pp. 241‒251Search in Google Scholar
14 Hougardy, H. P.: Anlassen von Martensit und Bainit. Vergütung oder Verspröden? – Teil 2: Erläuterungen der Vorgänge aus den Gefügen. Härterei-Techn. Mitt. 33 (1978) 5, pp. 252‒259Search in Google Scholar
15 Horn, R. M.; Ritchie, R. O.: Mechanisms of tempered martensite embrittlement in low alloy steels. Metall. Trans. A 9 (1978), pp. 1039‒105310.1007/BF02652208Search in Google Scholar
16 Sarikaya, M.; Jhingan, A. K.; Thomas, G.: Retained austenite and tempered martensite embrittlement in medium carbon steels. Metall. Trans. A 14 (1983), pp. 1121‒1133Search in Google Scholar
17 DIN 50115 1991-04: Kerbschlagbiegeversuch – Besondere Probenformen und Auswerteverfahren. Beuth, Berlin, 1991Search in Google Scholar
18 Ludwigson, D. C.; Berger, J. A.: Plastic behaviour of metastable austenitic stainless steels. J. Iron Steel Inst. 207 (1969), pp. 63‒69Search in Google Scholar
19 Matsumura, O.; Sakuma, Y.; Takechi, H.: TRIP and its kinetic aspects in austempered 0.4C-1.5Si-0.8Mn steel. Scr. Metall. 21 (1987), pp. 1301‒130610.1016/0036-9748(87)90103-7Search in Google Scholar
20 Kaar, S.; Schneider, R.; Krizan, D.; Béal, C.; Sommitsch, C.: Influence of the phase transformation behaviour on the microstructure and mechanical properties of a 4.5 wt.-% Mn Q&P steel. HTM J. Heat Treatm. Mat. 74 (2019) 2, pp. 70‒83, DOI:10.3139/105.11038110.3139/105.110381Search in Google Scholar
21 Kaar, S.; Krizan, D.; Schneider, R.; Sommitsch, C.: Impact of Si and Al on Microstructural evolution and mechanical properties of lean medium manganese quenching and partitioning steels. Steel Res. Int. 91 (2020) 10, 2000181, DOI:10.1002/srin.20200018110.1002/srin.202000181Search in Google Scholar
22 Nasim, M.; Edwards, B. C.; Wilson, E. A.: A study of grain boundary embrittlement in an Fe-8 %Mn Alloy. Mat. Sci. Eng. A 281 (2000) 1-2, pp. 56‒67, DOI:10.1016/s0921-5093(99)00734-010.1016/s0921-5093(99)00734-0Search in Google Scholar
23 Nikbakht, F.; Nasim, N.; Davies, C.; Wilson, E. A.; Adrian, H.: Isothermal embrittlement of Fe-8Mn alloys at 450 °C. Mater. Sci. and Technol. 26 (2010) 5, pp. 552‒558, DOI:10.1179/174328409x40561610.1179/174328409x405616Search in Google Scholar
24 Kaar, S.; Schneider, R.; Krizan, D.; Béal, C.; Sommitsch, C.: Influence of the quenching and partitioning process on the transformation kinetics and hardness in a lean medium manganese TRIP steel. Metals 9 (2019) 3, 533, DOI:10.3390/met903035310.3390/met9030353Search in Google Scholar
25 Girault, E.; Martens, A.; Jacques, P.; Houbaert, Y.; Verlinden, B.; Van Humbeeck, J.: Comparison of the effects of silicon and aluminum on the tensile behaviour of multiphase TRIP-assisted steels. Scr. Mater. 44 (2001) 6, pp. 885‒892, DOI:10.1016/s1359-6462(00)00697-710.1016/s1359-6462(00)00697-7Search in Google Scholar
26 Paravicini Bagliani, E.; Santofimia, M. J.; Zhao, L.; Sietsma, J.; Anelli, E.: Microstructure, tensile and toughness properties after quenching and partitioning treatments of a medium-carbon steel. Mater. Sci. Eng. A 559 (2013), pp. 486‒496, DOI:10.1016/j.msea.2012.08.13010.1016/j.msea.2012.08.130Search in Google Scholar
27 Mahieu, J.; De Cooman, B. C.; Claessens, S.: Phase transformation and mechanical properties of Si-free CMnAl transformation-induced plasticity-aided steel. Metall. Mater. Trans. A 33 (2002) 8, pp. 2573‒2580, DOI:10.1007/s11661-002-0378-910.1007/s11661-002-0378-9Search in Google Scholar
28 Steineder, K.; Krizan, D.; Schneider, R.; Béal, C.; Sommitsch, C.: On the damage behavior of a 0.1C6Mn medium-Mn steel, Steel Res. Int. 89 (2017) 9, 1700378, DOI:10.1002/srin.20170037810.1002/srin.201700378Search in Google Scholar
© 2021 Walter de Gruyter GmbH, Berlin/Boston, Germany