The medium-Mn steel is a promising third-generation automobile steel. Its chemical composition, microstructure, and thermal and mechanical properties are introduced and a warm-stamping process for the medium-Mn steel is proposed. The optimal process parameters are identified through the design of experiments (DOE) and range analysis. The evaluated experimental indexes include tensile strength, elongation, and hardness. The optimal forming process consists of an austenitization temperature of 840 °C, a soaking time of 4 min, and an initial stamping temperature of 500 °C. The proposed process was applied to the warm stamping of an automotive B-pillar. The microstructure of ultrafine, uniform, and complete martensite laths was obtained. The formed part exhibits approximately 1420 MPa tensile strength, over 11% elongation and 460 HV hardness. The optimal warm-stamping process has proved effective and applicable for forming medium-Mn steel parts. It will help promote the application of the third-generation automotive steels.
References
1.
Bardelcik
, A.
, Christopher
, P.
, Winkler
, S.
, Wells
, M. A.
, and Worswick
, M. J.
, 2010
, “Effect of Cooling Rate on the High Strain Rate Properties of Boron Steel
,” Int. J. Impact Eng.
, 37
(6
), pp. 694
–702
.2.
Kim
, J. T.
, Jeon
, Y. P.
, Kim
, B. M.
, and Kang
, C. G.
, 2012
, “Die Design for a Center Pillar Part by Process Analysis of Hot Stamping and Its Experimental Verification
,” Int. J. Precis. Eng. Manuf.
, 13
(9
), pp. 1051
–1057
.3.
Turetta
, A.
, Bruschi
, S.
, and Ghiotti
, A.
, 2006
, “Investigation of 22MnB5 Formability in Hot Stamping Operations
,” J. Mater. Process. Technol.
, 177
(1–3
), pp. 396
–400
.4.
Merklein
, M.
, and Lechler
, J.
, 2006
, “Investigation of the Thermo-Mechanical Properties of Hot Stamping Steels
,” J. Mater. Process. Technol.
, 177
(1–3
), pp. 452
–455
.5.
Kolleck
, R.
, Veit
, R.
, Merklein
, M.
, Lechler
, J.
, and Geiger
, M.
, 2009
, “Investigation on Induction Heating for Hot Stamping of Boron Alloyed Steels
,” CIRP Ann. Manuf. Technol.
, 58
(1
), pp. 275
–278
.6.
Chang
, Y.
, Meng
, Z. H.
, Ying
, L.
, Li
, X. D.
, Ma
, N.
, and Hu
, P.
, 2011
, “Influence of Hot Press Forming Techniques on Properties of Vehicle High Strength Steels
,” J. Iron Steel Res. Int.
, 18
(5
), pp. 59
–63
.7.
Zhao
, K. M.
, Chang
, Y.
, Hu
, P.
, and Wu
, Y. C.
, “Influence of Rapid Cooling Pretreatment on Microstructure and Mechanical Property of Hot Stamped AHSS Part
,” J. Mater. Process. Technol.
(in press).8.
Karbasian
, H.
, and Tekkaya
, A. E.
, 2010
, “A Review on Hot Stamping
,” J. Mater. Process. Technol.
, 210
(15
), pp. 2103
–2118
.9.
Abbasi
, M.
, Saeed-Akbari
, A.
, and Naderi
, M.
, 2012
, “The Effect of Strain Rate and Deformation Temperature on the Characteristics of Isothermally Hot Compressed Boron-Alloyed Steel
,” Mater. Sci. Eng. A
, 538
, pp. 356
–363
.10.
Ikeuchi
, K.
, and Yanagimoto
, J.
, 2011
, “Valuation Method for Effects of Hot Stamping Process Parameters on Product Properties Using Hot Forming Simulator
,” J. Mater. Process. Technol.
, 211
(8
), pp. 1441
–1447
.11.
Liu
, H. P.
, Lu
, X. W.
, Jin
, X. J.
, Dong
, H.
, and Shi
, J.
, 2011
, “Enhanced Mechanical Properties of a Hot Stamped Advanced High-Strength Steel Treated by Quenching and Partitioning Process
,” Scr. Mater.
, 64
(8
), pp. 749
–752
.12.
Shi
, J.
, Sun
, X. J.
, Wang
, M. Q.
, Hui
, W. J.
, Dong
, H.
, and Cao
, W. Q.
, 2010
, “Enhanced Work-Hardening Behavior and Mechanical Properties in Ultrafine-Grained Steels With Large-Fractioned Metastable Austenite
,” Scr. Mater.
, 63
(8
), pp. 815
–818
.13.
Wang
, C. Y.
, 2010
, “Investigation on 30GPa% Grade Ultrahigh-Strength Martensitic-Austenitic Steels
,” Ph.D. thesis, Central Iron and Steel Research Institute, Beijing, China (in Chinese).14.
Han
, Q.
, Bi
, W.
, Jin
, X.
, Xu
, W.
, Wang
, L.
, Xiong
, X.
, Wang
, J.
, and Belager
, P.
, 2015
, “Low Temperature Hot Forming of Medium-Mn Steel
,” 5th International Conference on Hot Sheet Metal Forming of High-Performance Steel
, Toronto, ON
, pp. 381
–390
.15.
Jin
, J.
, and Shi
, J.
, 2000
, “Diagnostic Feature Extraction From Stamping Tonnage Signals Based on Design of Experiments
,” ASME J. Manuf. Sci. Eng.
, 122
(2
), pp. 360
–369
.16.
Wang
, H. P.
, Zhao
, K. M.
, Hu
, P.
, Fu
, Z. C.
, and Bao
, J. R.
, 2011
, “Investigation and Correction of Surface Distortion in Dies With Typical Depression Features
,” ASME J. Manuf. Sci. Eng.
, 133
(4
), p. 041004
.17.
Li
, S. H.
, He
, J.
, Xia
, Z. C.
, Zeng
, D.
, and Hou
, B.
, 2014
, “Bifurcation Analysis of Forming Limits for an Orthotropic Sheet Metal
,” ASME J. Manuf. Sci. Eng.
, 136
(5
), p. 051005
.18.
Hasan
, R.
, Kasikci
, T.
, Tsukrov
, I.
, and Kinsey
, B.
, 2014
, “Numerical and Experimental Investigations of Key Assumptions in Analytical Failure Models for Sheet Metal Forming
,” ASME J. Manuf. Sci. Eng.
, 136
(1
), p. 011013
.19.
Cui
, J. J.
, Lei
, C. X.
, Xing
, Z. W.
, and Li
, C. F.
, 2012
, “Microstructure Distribution and Mechanical Properties Prediction of Boron Alloy During Hot Forming Using FE Simulation
,” Mater. Sci. Eng. A
, 535
, pp. 241
–251
.20.
Chang
, Y.
, Li
, X. D.
, Zhao
, K. M.
, Wang
, C. Y.
, Zheng
, G. J.
, Hu
, P.
, and Dong
, H.
, 2015
, “Influence of Stress on Martensitic Transformation and Mechanical Properties of Hot Stamped AHSS Parts
,” Mater. Sci. Eng. A
, 629
, pp. 1
–7
.21.
Wang
, C. Y.
, Shi
, J.
, Cao
, W. Q.
, and Dong
, H.
, 2010
, “Characterization of Microstructure Obtained by Quenching and Partitioning Process in Low Alloy Martensitic Steel
,” Mater. Sci. Eng. A
, 527
(15
), pp. 3442
–3449
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