Abstract
A novel design and manufacturing method, dubbed “precast,” of the cooling system and tools for a hot forming process was proposed in this paper. The integrated structures of the punch and blank holder were determined by analyzing the bending and reverse-bending deformation of the forming parts. The desired crashworthiness performance of an automotive front bumper constructed with this process was obtained by a tailored phase transformation, which generated martensite-bainite in the middle and full martensite transformation in the corner areas. Varying cooling effects in the formed parts caused the highest temperature to be located in the bottom and the lowest on the end of the formed parts. Moreover, the microstructural distributions demonstrated that the bottom possessed a relatively lower content of martensite, while, conversely, the end possessed a higher content. This was precisely the most desired phase distributions for the hot formed parts. For the six-process cycle stamping, the temperatures reached a stable status after an initial rapid increase in the first three process cycles. The microstructural results verified the feasibility of the hot forming tools under multiprocess cycles.
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J.J. Cui, G.Y. Sun, J.R. Xu, X.D. Huang, and G.Y. Li, A Method to Evaluate the Formability of High-Strength Steel in Hot Stamping, Mater. Des., 2015, 77, p 95–109
H.Z. Li, X. Wu, and G.Y. Li, Prediction of Forming Limit Diagrams for 22MnB5 in Hot Stamping Process, J. Mater. Eng. Perform., 2013, 22, p 2131–2140
J.J. Cui, C.X. Lei, Z.W. Xing, C.F. Li, and S.M. Ma, Predictions of the Mechanical Properties and Microstructure Evolution of High Strength Steel in Hot Stamping, J. Mater. Eng. Perform., 2012, 21, p 2241–2254
P. Bosetti, S. Bruschi, T. Stoehr, J. Lechler, and M. Merklein, Interlaboratory Comparison for Heat Transfer Coefficient Identification in Hot Stamping of High Strength Steels, Int. J. Mater. Form., 2010, 3(1), p 817–820
M. Nikravesh, M. Naderi, G.H. Akbari, and W. Bleck, Phase Transformations in a Simulated Hot Stamping Process of the Boron Bearing Steel, Mater. Des., 2015, 84, p 18–24
J. Lechler, M. Merklein, and M. Geiger, Determination of Thermal and Mechanical Material Properties of Ultra-High Strength Steels for Hot Stamping, Steel Res. Int., 2008, 79, p 98–104
B. Abdulhay, B. Bourouga, and C. Dessain, Thermal Contact Resistance Estimation: Influence of the Pressure Contact and the Coating Layer During a Hot Forming Process, Int. J. Mater. Form., 2012, 5, p 1–15
H.S. Liu, Z.W. Xing, J. Bao, and B.Y. Song, Investigation of the Hot-Stamping Process for Advanced High-Strength Steel Sheet by Numerical Simulation, J. Mater. Eng. Perform., 2010, 19, p 325–334
S. Li, L.H. Zhou, X.C. Wu, Y. Zhang, and J.W. Li, The Influence of Thermal Conductivity of Die Material on the Efficiency of Hot-Stamping Process, J. Mater. Eng. Perform., 2016, 25, p 4848–4867
H.S. Liu, C.X. Lei, and Z.W. Xing, Cooling System of Hot Stamping of Quenchable Steel BR1500HS: Optimization and Manufacturing Methods, Int. J. Adv. Manuf. Technol., 2013, 69, p 211–223
M. Abbasi, M. Naderi, and A. Saeed-Akbari, Isothermal versus Non-Isothermal Hot Compression Process: A Comparative Study on Phase Transformations and Structure–Property Relationships, Mater. Des., 2013, 45, p 1–5
Ch. Hopmann and P. Nikoleizig, Inverse Thermal Mold Design for Injection Molds, Int. J. Mater. Form., 2012, 1, p 1–12. https://doi.org/10.1007/s12289-016-1334-3
H. Steinbeiss, H. So, T. Michelitsch, and H. Hoffmann, Method for Optimizing the Cooling Design of Hot Stamping Tools, Prod. Eng. Res. Devel., 2007, 1, p 149–155
H. Hoffmann, H. So, and H. Steinbeiss, Design of Hot Stamping Tools with Cooling System, CIRP Ann. Manuf. Technol., 2007, 56, p 269–272
K. Mori, T. Maeno, and K. Mongkolkaji, Tailored Die Quenching of Steel Parts Having Strength Distribution Using Bypass Resistance Heating in Hot Stamping, J. Mater. Process. Technol., 2013, 213, p 508–514
M. Merklein, M. Wieland, M. Lechler, S. Bruschi, and A. Ghiotti, Hot Stamping of Boron Steel Sheets with Tailored Properties: A Review, J. Mater. Process. Technol., 2016, 228, p 11–24
T. Stöhr, M. Merklein, and J. Lechler, Investigations on Different Strategies for Influencing the Microstructural Properties with Respect to Partial Hot Stamping. In: 2nd International Conference on Hot Sheet Metal Forming of High-Performance Steel, ed. by M. Merklein, 15–17 June 2009 (Luleå), Verlag Wissenschaftliche Scripten, 2009, p 273–281
J. Brecht, B. Goeddeke, and K. Mongkolkaji, Warmgeformte Tailor Rolled Products, Funktionsoptimaler Leichtbau für die Fahrzeugkarosserie, In: Proceedings of the 8th Erlanger Workshop Warmblechumformung, ed. by M. Merklein, 12 Nov 2013 (Erlangen), Lehrstuhl für Fertigungstechnologie, p 85–94 (in German)
Y.Q. Zhu and J.L. Wang, Study of a SUV Bumper’s Crashworthiness Based on TRB Structure, Front. Mech. Eng., 2013, 4, p 53–56
H. Karbasian A. Brosiu, A. E. Tekkaya, J. Lechler, and M. Merklein, Numerical process design of hot stamping processes based on verified thermo-mechanical characteristics, In: Materials Science and Technology Conference (MS&T), ed. by M. Merklein, 5–9 October 2008 (Pittsburgh), p. 1733–1743.
H.S. Park and X.P. Dang, Development of a Smart Plastic injection mold with conformal cooling channels, Procedia. Manuf., 2017, 10, p 48–59
X.P. Li, F.W. Liu, and N.N. Gong, P. Huang and C. YANG, Enhancing the joining strength of injection-molded polymer-metal hybrids by rapid heating and cooling, J. Mater. Process. Technol., 2017, 249, p 386–393
Acknowledgments
This project is supported by the Key Project of Chinese National Programs (No. 2016YFB0101704) and the National Key Research and Development Program of Hunan Province (2017GK2090). We thank Sara Maccagnano-Zacher, Ph.D., from Liwen Bianji, Edanz Editing China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.
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Ou, H., Zhang, X., Xu, J. et al. Mechanical Properties and Microstructure of High-Strength Steel Controlled by Hot Stamping Process. J. of Materi Eng and Perform 27, 4025–4035 (2018). https://doi.org/10.1007/s11665-018-3290-1
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DOI: https://doi.org/10.1007/s11665-018-3290-1