The effect of various versions of quenching and partitioning (Q&P) and austempering plus tempering (A&T) processes on the combined properties and microstructure of a 0.2C–0.8Si–2.2Mn bainitic steel has been investigated. Results show that the steel exhibits a higher value of product of strength and elongation (PSE) than that reported before with similar compositions. The one-step Q&P process at 230°C and A&T process at 450°C can result in a toughness higher than 80 J cm−2 and a relatively high PSE (above 29.8 GPa%). The alloy design of this steel is suggested to be beneficial for industrial production because there is a big window for similar PSE. The long-partitioning time (1 h) has good effect on combined properties.
ZhangK., LiuP., LiW., GuoZ. H. and RongY. H.: ‘Ultrahigh strength–ductility steel treated by a novel quenching–partitioning–tempering process’, Mater. Sci. Eng., A, 2014, 619, 205–211. doi: 10.1016/j.msea.2014.09.100
2.
SunJ., YuH., WangS. Y. and FanY. F.: ‘Study of microstructural evolution, microstructure–mechanical properties correlation and collaborative deformation-transformation behavior of quenching and partitioning (Q&P) steel’, Mater. Sci. Eng., A, 2014, 596, 89–97. doi: 10.1016/j.msea.2013.12.054
3.
GaoG. H., ZhangH., GuiX. L., LuoP., TanZ. L. and BaiB. Z.: ‘Enhanced ductility and toughness in an ultrahigh-strength Mn–Si–C–Cr steel: the great potential of ultrafine filmy retained austenite’, Acta Mater., 2014, 76, 425–433. doi: 10.1016/j.actamat.2014.05.055
4.
WangY., ZhangK., GuoZ. H., ChenN. L. and RongY. H.: ‘A new effect of retained austenite on ductility enhancement in high strength bainitic steel’, Mater. Sci. Eng., A, 2012, 552, 288–294. doi: 10.1016/j.msea.2012.05.042
5.
GaoG. H., ZhangH., TanZ. L., LiuW. B. and BaiB. Z.: ‘A carbide-free bainite/martensite/austenite triplex steel with enhanced mechanical properties treated by a novel quenching–partitioning–tempering process’, Mater. Sci. Eng., A, 2013, 559, 165–169. doi: 10.1016/j.msea.2012.08.064
6.
HellJ. C., DehmasM., AllainS., PradoJ. M., HazotteA. and ChateauJ. P.: ‘Microstructure–properties relationships in carbide-free bainitic steels’, ISIJ Int., 2011, 51, (10), 1724–1732. doi: 10.2355/isijinternational.51.1724
7.
YanS., LiuX. H., LiuW. J., LanH. F. and WuH. Y.: ‘Comparison on mechanical properties and microstructure of a C–Mn–Si steel treated by quenching and partitioning (Q&P) and quenching and tempering (Q&T) processes’, Mater. Sci. Eng., A, 2014, 620, 58–66. doi: 10.1016/j.msea.2014.09.047
8.
PutatundaS. K., MartisC. and BoileauJ.: ‘Influence of austempering temperature on the mechanical properties of a low carbon low alloy steel’, Mater. Sci. Eng., A, 2011, 528, 5053–5059. doi: 10.1016/j.msea.2011.03.038
9.
SilvaE. P. D., XuW., FojerC. and HoubaertY.: ‘Phase transformations during the decomposition of austenite below Ms in a low-carbon steel’, Mater. Charact., 2014, 95, 85–93. doi: 10.1016/j.matchar.2014.06.003
10.
GrajcarA. and KrztońH.: ‘Effect of isothermal bainitic transformation temperature on retained austenite fraction in C–Mn–Si–Al–Nb–Ti TRIP-type steel’, J. Achiev. Mater. Manuf. Eng., 2009, 35, (2), 169–176.
TomitaY. and OkabayashiK.: ‘Mechanical properties of 0.40 pct C–Ni–Cr–Mo high strength steel having a mixed structure of martensite and bainite’, Metall. Mater. Trans. A, 1985, 16, 73–82. doi: 10.1007/BF02656714
13.
TomitaY. and OkabayashiK.: ‘Improvement in lower temperature mechanical properties of 0.40 pct C–Ni–Cr–Mo ultrahigh strength steel with the second phase lower bainite’, Metall. Mater. Trans. A, 1983, 14, 2387–2393. doi: 10.1007/BF02663314
14.
GazderF. A. A. A., De CoomanA. K. B. C. and PerelomaE. V.: ‘The effect of processing parameters on the microstructure and mechanical properties of low-Si transformation-induced plasticity steels’, J. Mater. Sci., 2014, 49, 2960–2974. doi: 10.1007/s10853-013-8008-z
15.
ZhangJ., DingH., MisraR. D. K. and WangC.: ‘Enhanced stability of retained austenite and consequent work hardening rate through pre-quenching prior to quenching and partitioning in a Q–P microalloyed steel’, Mater. Sci. Eng., A, 2014, 611, 252–256. doi: 10.1016/j.msea.2014.05.074
16.
JinJ. W., ParkY. D., NamD. G., LeeS. B., KimS. I., KangN. and ChoK. M.: ‘Comparative analysis of strengthening with respect to microstructural evolution for 0.2 carbon DP, TRIP, Q&P steels’, Kor. J. Mater. Res., 2009, 19, (6), 293–299. doi: 10.3740/MRSK.2009.19.6.293
17.
KobayashiJ., InaD., YoshikawaN. and SugimotoK. I.: ‘Effects of the addition of Cr, Mo and Ni on the microstructure and retained austenite characteristics of 0.2% C–Si–Mn–Nb ultrahigh-strength TRIP-aided bainitic ferrite steels’, ISIJ Int., 2012, 52, (10), 1894–1901. doi: 10.2355/isijinternational.52.1894
18.
KobayashiJ., InaD., FutamuraA. and SugimotoK. I.: ‘Fracture toughness of an advanced ultrahigh-strength TRIP-aided steel’, ISIJ Int., 2014, 54, (4), 955–962. doi: 10.2355/isijinternational.54.955
19.
ClarkeA. J., SpeerJ. G., MillerM. K., HackenbergR. E., EdmondsD. V., MatlockD. K., RizzoF. C., ClarkeK. D. and MoorE. D.: ‘Carbon partitioning to austenite from martensite or bainite during the quench and partition (Q&P) process: acritical assessment’, Acta Mater., 2008, 56, 16–22. doi: 10.1016/j.actamat.2007.08.051
20.
SpeerJ. G., MatlockD. K., De CoomanB. C. and SchrothJ. G.: ‘Carbon partitioning into austenite after martensite transformation’, Acta Mater., 2003, 51, 2611–2622. doi: 10.1016/S1359-6454(03)00059-4
21.
SpeerJ. G., EdmondsD. V., RizzoF. C. and MtalockD. K.: ‘Partitioning of carbon from supersaturated plates of ferrite, with application to steel processing and fundamentals of the bainite transformation’, Curr. Opin. Solid State Mater. Sci., 2004, 8, 219–237. doi: 10.1016/j.cossms.2004.09.003
22.
SpeerJ. G., Rizzo AssunçãoF. C., MatlockD. K. and EdmondsD. V.: ‘The “quenching and partitioning” process: background and recent progress’, Mater. Res., 2005, 8, (4), 417–423. doi: 10.1590/S1516-14392005000400010
23.
EdmondsD. V., HeK., RizzoF. C., De CoomanB. C., MatlockD. K. and SpeerJ. G.: ‘Quenching and partitioning martensite – a novel steel heat treatment’, Mater. Sci. Eng., A, 2006, 438–440, 25–34. doi: 10.1016/j.msea.2006.02.133
24.
KnijfD. D., PetrovR., FöjerC. and KestensL. A. I.: ‘Effect of fresh martensite on the stability of retained austenite in quenching and partitioning steel’, Mater. Sci. Eng., A, 2014, 615, 107–115. doi: 10.1016/j.msea.2014.07.054
25.
HsuT. Y. and XuZ. Y.: ‘Design of structure, composition and heat treatment process for high strength steel’, Mater. Sci. Forum, 2007, 561–565, 2283–2286. doi: 10.4028/www.scientific.net/MSF.561-565.2283
26.
ZhouS., ZhangK., WangY., GuJ. F. and RongY. H.: ‘High strength–elongation product of Nb-microalloyed low-carbon steel by a novel quenching–partitioning–tempering process’, Mater. Sci. Eng., A, 2011, 528, 8006–8012. doi: 10.1016/j.msea.2011.07.008
27.
SomaniM. C., PorterD. A., KarjalainenL. P. and MisraR. D. K.: ‘On various aspects of decomposition of austenite in a high-silicon steel during quenching and partitioning’, Metall. Mater. Trans. A, 2014, 45, 1247–1257. doi: 10.1007/s11661-013-2053-8
28.
HuangX. F., LiuW. L., HuangY. Y., ChenH. and HuangW. G.: ‘Effect of a quenching–long partitioning treatment on the microstructure and mechanical properties of a 0.2C% bainitic steel’, J. Mater. Process. Technol., 2015, 222, 181–187. doi: 10.1016/j.jmatprotec.2015.03.010
29.
SantofimiaM. J., ZhaoL., PetrovR., KwakernaakC., SloofW. G. and SietsmaJ.: ‘Microstructural development during the quenching and partitioning process in a newly designed low-carbon steel’, Acta Mater., 2011, 59, 6059–6068. doi: 10.1016/j.actamat.2011.06.014
30.
ZhangJ., DingH., WangC., ZhaoJ. W. and DingT.: ‘Work hardening behaviors of a low carbon Nb-microalloyed Si–Mn quenching–partitioning steel with different cooling styles’, Mater. Sci. Eng., A, 2013, 585, 132–138. doi: 10.1016/j.msea.2013.07.046
31.
ChenY., ZhangD. T., LiuY. C., LiH. J. and XuD. K.: ‘Effect of dissolution and precipitation of Nb on the formation of acicular ferrite/bainite ferrite in low-carbon HSLA steels’, Mater. Charact., 2013, 84, 232–239. doi: 10.1016/j.matchar.2013.08.005
