High Strength-Ductility Nb-microalloyed Low Martensitic Carbon Steel: Novel Process and Mechanism

doi:10.1007/s40195-015-0321-x

摘要/Abstract

Abstract:

A low-carbon Nb-microalloyed Fe-Mn-Si-based steel was treated by a novel quenching-partitioning-tempering (Q-P-T) process as a modified quenching and partitioning (Q&P) process. After processed by Q-P-T treatment, this steel exhibits excellent mechanical properties such as high product of strength and elongation. The addition of Nb markedly raises both the yield strength and tensile strength of Q-P-T martensitic steel, especially the yield strength, which can be attributed to the strong grain refinement strengthening and precipitation strengthening of Nb. The Nb addition can also lead to a little increase in ductility. The Nb-microalloyed steel treated by Q-P-T process displays much higher ductility than that treated by traditional quenching and tempering (Q&T) process. The mechanisms of Q-P-T process on ductility enhancement were fully analyzed and can be attributed to high quenching temperature and considerable amount of retained austenite.

Key words: Heat treatment, Mechanical properties, Microstructure, Microalloyed steel, Martensitic transformation

. [J]. 金属学报英文版, 2015, 28(10): 1264-1271.

Ke Zhang, Ping Liu, Wei Li, Zheng-Hong Guo, Yong-Hua Rong. High Strength-Ductility Nb-microalloyed Low Martensitic Carbon Steel: Novel Process and Mechanism[J]. Acta Metallurgica Sinica (English Letters), 2015, 28(10): 1264-1271.

图/表 8

Table 1 Chemical compositions of experimental steels (in wt pct)

Steel	C	Mn	Si	Nb	Fe	Ac₃ (°C)	M_s (°C)	M_f (°C)
Nb00	0.2	1.54	1.58	-	Bal.	904 ± 5	415 ± 5	173 ± 3
Nb03	0.19	1.52	1.57	0.029	Bal.	911 ± 5	395 ± 5	171 ± 3

Fig. 1 Schematic heat treatment diagram of the Q-P-T, Q&P and Q&T processes, where the abbreviation of M.S.Q. and W.Q. represent molten salt quenching and water quenching, respectively

Fig. 2 Tensile engineering stress and strain curves of the Nb00 steel and Nb03 steel treated by Q-P-T, Q&P and Q&T processes

Table 2 Mechanical properties of the steels treated by Q&T, Q&P and Q-P-T processes

Steel	Process	σ_0.2 (MPa)	σ_b (MPa)	δ_u (%)	δ_b (%)	σ_b × δ_b (GPa%)
Nb00	Q&T	1149 ± 7	1266 ± 9	3.8 ± 0.3	11.7 ± 0.8	14.8
Nb03	Q&T	1227 ± 13	1337 ± 14	4.0 ± 0.1	12.2 ± 0.5	16.3
Nb00	Q&P	1094 ± 17	1236 ± 9	5.4 ± 0.8	13.9 ± 0.8	17.2
Nb03	Q-P-T	1146 ± 15	1247 ± 15	6.0 ± 0.3	15.0 ± 0.5	18.7

Fig. 3 XRD patterns of the Nb00 steel and Nb03 steel treated by Q-P-T, Q&P and Q&T processes

Fig. 4 TEM micrographs of the Nb00 steel treated by Q&T and Q&P processes, respectively: a Q&T, bright-field image; b Q&T, dark-field image and \(\bar{1}\bar{1}1_{\gamma }\) and \(1\bar{1}1_{\gamma }\) diffraction spots of retained austenite; c Q&P, bright-field images; d Q&P, dark-field image and \(\bar{1}\bar{1}1_{\gamma }\) and \(1\bar{1}1_{\gamma }\) diffraction spots of retained austenite

Fig. 5 TEM micrographs of the Nb03 steel treated by Q&T and Q&P processes: a Q&T, bright-field image; b Q&T, dark-field image and \(11\bar{1}_{\text{NbC}}\) diffraction spots of retained austenite; c Q&P, bright-field images; d Q&P, dark-field image and \(11\bar{1}_{\text{NbC}}\) diffraction spots of retained austenite

Fig. 6 SEM fractographs of the Nb03 steel treated by Q&T a, Q-P-T b processes

参考文献 39

[1]	J. Van Slycken, P. Verleysen, J. Degrieck, J. Bouquerel, B.C. De Cooman, Mater. Sci. Eng., A 460-461, 516(2007)
[2]	Y.I. Son, Y.K. Lee, K.T. Park, C.S. Lee, D.H. Shin, Acta Mater. 53, 3125(2005)
[3]	B.C. De Cooman, Curr. Opin. Solid State Mater. Sci. 8, 285(2004)
[4]	J. Shi, X. Sun, M. Wang, W. Hui, H. Dong, W. Cao, Scr. Mater. 63, 815(2010)
[5]	J.G. Speer, D.K. Matlock, B.C. De Cooman, J.G. Schroth, Acta Mater. 51, 2611(2003)
[6]	J.G. Speer, D.V. Edmonds, F.C. Rizzo, D.K. Matlock, Curr. Opin. Solid State Mater. Sci. 8, 219(2004)
[7]	J.G. Speer, D.K. Matlock, B.C. De Cooman, J.G. Schroth, Scr. Mater. 52, 83(2005)
[8]	D.V. Edmonds, K. He, F.C. Rizzo, B.C. De Cooman, D.K. Matlock, J.G. Speer, Mater. Sci. Eng., A 438-440, 25(2006)
[9]	A.J. Clarke, J.G. Speer, M.K. Miller, R.E. Hackenberg, D.V. Edmonds, D.K. Matlock, Acta Mater. 56, 16(2008)
[10]	T.Y. Hsu, Mater. Sci. Forum 561-565, 2283(2007)
[11]	X.D. Wang, B.X. Huang, L. Wang, Y.H. Rong, Metall. Mater. Trans. A 39, 1 (2008)
[12]	D.P. Koistinen, R.E. Marburger, Acta Metall. 7, 59(1959)
[13]	X.D. Wang, N. Zhong, Y.H. Rong, T.Y. Hsu, J. Mater. Res. 24, 260(2009)
[14]	K. Zhang, W.Z. Xu, Z.H. Guo, Y.H. Rong, M.Q. Wang, H. Dong, Acta Metall. Sin. 47, 489(2011). (in Chinese)
[15]	N. Zhong, X.D. Wang, L. Wang, Y.H. Rong, Mater. Sci. Eng., A 506, 111 (2009)
[16]	V.F. Zackay, E.R. Parker, D. Fahr, R. Busch, ASM Trans. Q. 60, 252(1967)
[17]	R. Feng, M.H. Zhang, N.L. Chen, X.W. Zuo, Y.H. Rong, Acta Metall. Sin. 50, 498(2014). (in Chinese)
[18]	D. Webster, ASM Trans. Q. 61, 816(1968)
[19]	R. Ayer, P.M. Machmeier, Metall. Trans. A 24, 1943 (1993)
[20]	C.C. Wang, C. Zhang, Z.G. Yang, Micron 67, 112 (2014)
[21]	K. Zhang, M.H. Zhang, Z.H. Guo, N.L. Chen, Y.H. Rong, Mater. Sci. Eng., A 528, 8486 (2011)
[22]	S. Shao, S.N. Medyanik, Modell. Simul. Mater. Sci. Eng. 18, 055010(2010)
[23]	Y.H. Rong, Int. Heat Treat. Surf. Eng. 5, 145(2011)
[24]	Y. Wang, K. Zhang, Z.H. Guo, N.L. Chen, Y.H. Rong, Mater. Sci. Eng., A 552, 288 (2012)
[25]	S.W. Qin, Y. Liu, Q.G. Hao, Y. Wang, N.L. Chen, X.W. Zuo, Y.H. Rong, Metall. Mater. Trans. A 46, 1 (2015)
[26]	Q.G. Hao, Y. Wang, X.S. Jia, X.W. Zuo, N.L. Chen, Y.H. Rong, Acta Metall. Sin. (Engl. Lett.) 27, 444(2014)
[27]	S. Zhou, K. Zhang, Y. Wang, J.F. Gu, Y.H. Rong, Metall. Mater. Trans. A 43, 1026 (2012)
[28]	R.O. Ritchie, Nat. Mater. 10, 817(2011)
[29]	C.F. Wang, M.Q. Wang, J. Shi, W.J. Hui, H. Dong, J. Mater. Sci. Technol. 23, 659(2007)
[30]	P.A. Manohar, M. Ferry, T. Chandra, ISIJ Int. 38, 913(1998)
[31]	X.D. Wang, B.X. Huang, Y.H. Rong, L. Wang, in Proceedings of 3rd International Conference on Advanced Structural Steels (ICASS, Gyeongju, Korea, 2006), p. 1152
[32]	S. Morito, X. Huang, T. Furuhara, T. Maki, N. Hansen, Acta Mater. 54, 5323(2006)
[33]	X.D. Wang, W.Z. Xu, Z.H. Guo, L. Wang, Y.H. Rong, Mater. Sci. Eng., A 527, 3373 (2010)
[34]	K. Lu, L. Lu, S. Suresh, Science 324, 349 (2009)
[35]	X.L. Li, Z.H. Guo, Y.H. Rong, H.Y. Wu, S.F. Wu, Acta Metall. Sin. 50, 439(2014). (in Chinese)
[36]	C.L. Briant, Mater. Sci. Technol. 5, 138(1989)
[37]	S.S. Nayak, R. Anumolu, R.D.K. Misra, K.H. Kim, D.L. Lee, Mater. Sci. Eng., A 498, 442 (2008)
[38]	L. Lu, M.L. Sui, K. Lu, Science 287, 1463 (2000)
[39]	W.D. Callister Jr, Materials science and engineering: an introduction, 2nd edn. (Wiley, New York, 1985), p. 306