An Introduction to Advanced Hot-Formed Steel for Automobile

doi:10.1007/s40195-014-0076-9

Abstract

Abstract:

A recently developed advanced hot-formed (AHF) steel for automobile is introduced and three physical metallurgy concepts based on which the AHF steel was designed are reviewed, they are dynamic carbon partitioning (DCP), flash copper precipitation and bake toughening. AHF steel is an upgrade of the existing hot-formed steel especially suitable for making components with superior crashworthiness; it can be processed by regular hot stamping equipment and process. A kinetics model for DCP is expressed in detail, which can be used to calculate the volume fraction of retained austenite based on four materials and processing parameters. The flash copper precipitation used as an additional strengthening mechanism for AHF steel is also discussed and its ultrafast kinetics can be attributed to the enhancement of quenched-in vacancies on copper diffusion. Also, the bake toughening of AHF steel is addressed; the mechanism of which may be related to the elimination of the less stable block-like retained austenite.

Key words: Advanced hot-formed (AHF) steel, Dynamic carbon partitioning, Flash copper precipitation, Bake toughening, Hot stamping

W. J. Liu. An Introduction to Advanced Hot-Formed Steel for Automobile[J]. Acta Metallurgica Sinica (English Letters), 2014, 27(3): 373-382.

Figures/Tables 11

References 33

[1]	China world’s largest auto production site in 2013: report,(English News, Xinhua News, 2014), . Accessed 14 Jan 2014
[2]	Z. Wang, Y. Jin, Energy Sav. Environ. Prot.(in Chinese) 7, 17 (2008)
[3]	J.Aspacherin1st International Conference on Hot Sheet Metal Forming of High-Performance Steel(Kassel, Germany, 2008), p. 77
[4]	K.I. Mori, Trans. Nonferrous Met. Soc. China 22, s496(2012)10.1016/S1003-6326(12)61752-X
[5]	G.Berglundin1st International Conference on Hot Sheet Metal Forming of High-Performance Steel(Kassel, Germany, 2008), p. 175
[6]	M. Naderi, Ph.D. Thesis, RWTH Aachen, 2007
[7]	A. Mittal, Catalogue—European Edition, 2014
[8]	J.G. Speer, D.K. Matlock, B.C. DeCooman, J.G. Schroth, Acta Mater. 51, 2611(2003)10.1016/S1359-6454(03)00059-4
[9]	J.G. Speer, D.V. Edmonds, F.C. Rizzo, D.K. Matlock, Curr. Opin. Solid State Mater. 8, 219(2004)10.1016/j.cossms.2004.09.003
[10]	E. de Moor, S. Lacroix, A.J. Clarke, J. Penning, J.G. Speer, Metall. Mater. Trans. A 39, 2586(2008)10.1007/s11661-008-9609-z
[11]	E.De MoorC.FöjerA.J.ClarkeJ.PenningJ.G.SpeerinProceedings of the Conference on New Developments on Metallurgy and Applications of High-Strength Steels, ed. by T. Perez (TMS, Warrendale, 2009), p. 721
[12]	A.M.StreicherJ.G.SpeerD.K.MatlockB.C.DeCoomaninInternational Conference on Advanced High-Strength Sheet Steels for Automotive Applications Proceedings, ed. by J.G. Speer (AIST, Warrendale, 2004), p. 51
[13]	H. Liu, X. Lu, X. Jin, H. Dongb, J. Shi, Scr. Mater. 64, 749(2011)10.1016/j.scriptamat.2010.12.037
[14]	H. Karbasian, A.E. Tekkaya, J. Mater. Process. Technol. 210, 2103(2010)10.1016/j.jmatprotec.2010.07.019
[15]	B.C.de CoomanJ.G.SpeerI.Y.PyshmintsevN.Yoshinaga, Materials Design: The Key to Modern Steel Products, 1st edn. (Media Grips, Bad Harzburg, 2007), p. 176
[16]	S. Yan, X.H. Liu, W.J. Liu, H.F. Lan, H.Y. Wu, Acta Metall. Sin.(in Chinese) 49, 917 (2013)
[17]	T. Lin, Ph.D. thesis, University of Chinese Academy of Sciences, 2014 (in Chinese)
[18]	Y.N. Duan,Master Theses, Northeastern University, 2012 (in Chinese)
[19]	Y. Wang,Master Theses, Northeastern University, 2013 (in Chinese)
[20]	B.V.N.RaoG.ThomasinInternational Conference on Martensitic Transformations(HIT Press, Cambridge, l979) p. 12
[21]	M.SarikayaG.ThomasJ.W.SteedsinInternational Conference on Solid-solid Phase Transformations, ed. by H.I. Aaronson, D.E. Laughlin, R.F. Sekerka, C.M. Wayman, (TMS-AIME, Pittsburgh, 1982) p. 1421
[22]	T.Y. Hsu, X. Li, Acta Metall. Sin.(in Chinese) 19, 83 (1983)
[23]	T.Y. Hsu, J. Phys. IV 5, 351(1995)
[24]	L. Kaufman, M. Cohen, Prog. Metall. Phys. 7, 165(1958)10.1016/0502-8205(58)90005-4
[25]	T.Y. Hsu, H.B. Chang, Acta Metall. 32, 343(1984)10.1016/0001-6160(84)90107-X
[26]	V. Raghavan, D. Antia, Metall. Mater. Trans. A 27, 1127(1996)10.1007/BF02649781
[27]	C.L.MageeinPhase Transformations, (Arner. Soc. Metals, Metals Park, Ohio, 1970), p. l15
[28]	D.P. Koistinen, R.E. Marburger, Acta Metall. 7, 59(1959) doi: 10.1016/0001-6160(59)90170-1
[29]	J.M. Chilton, P.U. Kelly, Acta Metall. 16, 637(1968)10.1016/0001-6160(68)90137-5
[30]	Y. Okamura, M. Okushima, H. Tamehiro, T. Kasuya, M. Tanaka, R. Yamaba, H. Inoue, A. Seto, Nippon Steel Technol. Rep., No. 66(1995)
[31]	A.C.DamaskG.J.Dienes, Point Defects in Metals, 1st edn. (Gordon and Breach, New York/London, 1963)
[32]	S.T. Wu,Master Theses, Northeastern University, 2014 (in Chinese)
[33]	A. Kokosza, J. Pacyna, Arch. Mater. Sci. Eng. 31, 87(2008)

Steel	C	Si	Mn	Ni + Cr + Mo	Cu	B	Ti	Al	O	N	P	S	M_s (°C)
B	0.19	1.55	1.53	2.47	1.01	0.0027	0.033	0.025	0.0030	0.0029	0.008	0.004	310
C	0.19	1.46	0.55	1.41	–	0.0021	0.027	0.025	0.0028	0.0028	0.010	0.005	454
D	0.20	1.52	1.51	0.6	0.64	0.0032	0.030	0.025	0.0024	0.0030	0.010	0.006	406
E	0.39	1.56	1.54	2.44	1.40	0.0023	0.028	0.025	0.0026	0.0030	0.008	0.005	270*
F	0.25	1.0	–	1.03	–	0.003	–	0.54	–	–	–	–	426
G	0.21	1.0	0.35	1.02	–	0.003	–	0.494	–	–	–	–	451

Steel	C	Si	Mn	Ni + Cr + Mo	Cu	B	Ti	Al	O	N	P	S	M_s (°C)
B	0.19	1.55	1.53	2.47	1.01	0.0027	0.033	0.025	0.0030	0.0029	0.008	0.004	310
C	0.19	1.46	0.55	1.41	–	0.0021	0.027	0.025	0.0028	0.0028	0.010	0.005	454
D	0.20	1.52	1.51	0.6	0.64	0.0032	0.030	0.025	0.0024	0.0030	0.010	0.006	406
E	0.39	1.56	1.54	2.44	1.40	0.0023	0.028	0.025	0.0026	0.0030	0.008	0.005	270*
F	0.25	1.0	–	1.03	–	0.003	–	0.54	–	–	–	–	426
G	0.21	1.0	0.35	1.02	–	0.003	–	0.494	–	–	–	–	451

Steel	Treatment process				Mechanical properties			Ref.
Steel	Type	T_D (°C)	\( \dot{T}_{\text{ms}} \) (°C/s)	\( \dot{T}_{\text{Td}} \) (°C/s)	UTS (MPa)	El (%)	PSE (MPa%)	Ref.
B	HS-R	–	403	–	1,557	13.9	21,666	[19]
			385		1,623	13.7	22,202
			62		1,523	15.2	23,210
			2.5		1,429	16.08	22,978
	HS-E	200	24	0.6	1,463	15.3	22,384
	HS-E	200	24	0.2	1,428	16.6	23,717
C	HS-R		403		1,518	12.96	19,673
			385		1,521	17.2	26,161
			62		1,442	17.56	25,321
	HS-E	300	24	5	1,299	15.68	20,368
		300	24	1	1,334	15.42	20,570
		350	24	5.8	1,263	15.92	20,107
		350	24	1.2	1,252	16.48	20,633
D	HS-E	300	40	3	1,412	14.8	20,900	[16]
D	HS-E	300	40	1	1,326	16	21,200	[16]
E	HS-R		45		2,437	8.6	20,958	[17]
F	HS-R		~45		1,615	13.5	21,802	[18]
F	HS-E	350	24	11	1,534	15.4	23,623	[18]
G	HS-R	–	403	–	1,460	14.84	21,666	[19]
			385		1,456	15.65	22,786
			62		1,400	15.78	22,088

Steel	Treatment process				Mechanical properties			Ref.
Steel	Type	T_D (°C)	\( \dot{T}_{\text{ms}} \) (°C/s)	\( \dot{T}_{\text{Td}} \) (°C/s)	UTS (MPa)	El (%)	PSE (MPa%)	Ref.
B	HS-R	–	403	–	1,557	13.9	21,666	[19]
			385		1,623	13.7	22,202
			62		1,523	15.2	23,210
			2.5		1,429	16.08	22,978
	HS-E	200	24	0.6	1,463	15.3	22,384
	HS-E	200	24	0.2	1,428	16.6	23,717
C	HS-R		403		1,518	12.96	19,673
			385		1,521	17.2	26,161
			62		1,442	17.56	25,321
	HS-E	300	24	5	1,299	15.68	20,368
		300	24	1	1,334	15.42	20,570
		350	24	5.8	1,263	15.92	20,107
		350	24	1.2	1,252	16.48	20,633
D	HS-E	300	40	3	1,412	14.8	20,900	[16]
D	HS-E	300	40	1	1,326	16	21,200	[16]
E	HS-R		45		2,437	8.6	20,958	[17]
F	HS-R		~45		1,615	13.5	21,802	[18]
F	HS-E	350	24	11	1,534	15.4	23,623	[18]
G	HS-R	–	403	–	1,460	14.84	21,666	[19]
			385		1,456	15.65	22,786
			62		1,400	15.78	22,088

Steel	M_s (°C)	Treatment process				f_γ (%)	Ref.
Steel	M_s (°C)	Type	T_D (°C)	\( \dot{T}_{1} \)(°C/s)	\( \dot{T}_{2} \)(°C/s)	f_γ (%)	Ref.
B	310	HS-R	–	385		1.5, 4.6	[19, 32]
				62		3.24
				10		14
		HS-E	200	24	0.6	9.57	[19]
			250	24	1	10.07
			250	24	0.5	13.2
			280	24	1	13
C	454	HS-R	–	385		5.7	[16]
D	406	HS-E	300	40	3	6.1
D	406	HS-E			1	5.5
F	426	HS-R		385		3.23	[18]
				80		4.59
				45		11.76
				20		11.42
		HS-E	350	24	11	13.41
G	451	HS-R		385		1.02	[19]