Abstract
Hot stamping and successive quenching can significantly improve the strength of the hot-stamped part to above 1.5 GPa and has been widely used in automobile manufacturing. However, ultra-high strength brings high difficulty in cold blanking of such hot-stamped part: low tool life and low surface quality of the sheared edge. Local heating-aided hot blanking of quenched ultra-high-strength steel (UHSS) is proposed in order to reduce the blanking loading and thus improve the tool life. In this method, conduction heating technology is employed to locally heat the shear zone of the blank prior to blanking. The surface quality of the sheared edge is investigated under different process parameters by experiments and simulations. Cooling methods used in obtaining the quenched blank and heating temperature (HT) play an important role in conditioning the surface quality of the sheared edge. Microstructure of the shear zone for different cooling methods and heating temperatures as well as its effect on the surface quality of the sheared edge and the mechanical properties of material in the vicinity of sheared edge are studied by experiments and simulations. A finite element (FE)-coupled thermo-mechanical model is developed to model hot blanking process. Good agreement between simulation and experimental results are achieved. Relationships among blanking force, heating temperature, and tool clearance (TC) are determined. Both experiment and simulation results demonstrate that for heating temperature at 800 °C, hot blanking loading decreases sharply and relative burnish height is significantly increased compared with the case of heating temperature at 400 °C.
Similar content being viewed by others
References
Lim WS, Choi HS, Ahn SY, Kim BM (2009) Cooling channel design of hot stamping tools for uniform high-strength components in hot stamping process. Int J Adv Manufact Technol 70(5–8):1189–1203
Liu HS, Xing ZW, Lei CX (2012) Hot formation quality of high strength steel br1500hs for hot stamping without cooling system. Trans Nonferrous Metals Soc China 22:542–547
Liu HS, Lei CX, Xing ZW (2013) Cooling system of hot stamping of quenchable steel BR1500HS: optimization and manufacturing methods. Int J Adv Manufact Technol 69:211–223
Liu HS, Liu W, Bao J (2011) Numerical and experimental investigation into hot forming of ultra high strength steel sheet. J Mater Eng Perform 20:1–10
Kim HY, Park JK, Lee MG (2014) Phase transformation-based finite element modeling to predict strength and deformation of press-hardened tubular automotive part. Int J Adv Manuf 70:1787–1801
Bok HH, Choi JW, Barlat F, Suh DW, Lee MG (2015) Thermo-mechanical-metallurgical modeling for hot-press forming in consideration of the prior austenite deformation effect. Int J Plast 58:154–183
Bok HH, Lee MG, Kim HD, Moon MB (2010) Stress–strain response of low alloy steel at elevated temperature and its practical application to hot stamping. Met Mater Int 16(2):185–195
Åkerström P, Oldenburg M (2006) Austenite decomposition during press hardening of a boron steel-computational simulation and test. J Mater Process Technol 174:399–406
Xu Y, Shan ZD (2014) Design parameter investigation of cooling systems for UHSS hot stamping dies. Int J Adv Manufact Technol 70:257–262
Barcellona A, Palmeri D (2009) Effect of plastic hot deformation on the hardness and continuous cooling transformations of 22MnB5 microalloyed boron steel. Metall Mater Trans A 40:1160–1174
Zhu WF, Zhou JQ (2010) Optimal method for auto-body closure panel fitting using Hausdorff distance criteria. Int J Adv Manufact Technol 48:1019–1029
Hashmi MSJ, Mridha S, Naher S (2011) Innovative tools and tool steels for the blanking of press-hardened ultra high-strength manganese–boron steels. Adv Mater Res 264–265:123–128
Mackensen A, Golle M, Golle R, Hoffmann H (2010) Experimental investigation of the cutting force reduction during the blanking operation of AHSS sheet materials. Ann CIRP 59:283–286
Cora ÖN, Koc M (2009) Experimental investigation on wear resistance characteristics of alternative die materials for stamping of advanced high-strength steels (AHSS). Int J Mach Tools Manuf 49:897–905
So H, Faßmann D, Hoffmann H, Golle R, Schaper M (2012) An investigation of the blanking process of the quenchable boron alloyed steel 22MnB5 before and after hot stamping process. J Mater Process Technol 212:437–449
Picas I (2012) Mechanical behaviour of tools for shearing ultra high-strength steels: influence of the microstructure on fracture and fatigue micro-mechanisms of tool steels and evaluation of micro-mechanical damage in tools. A thesis for the degree of Doctor in the Universitat Politècnica de Catalunya,Fundació CTM Centre Tecnològic. 2012
Mori K, Abe Y, Kidoma Y, Kadarno P (2013) Slight clearance blanking of ultra-high strength steel sheets using punch having small round edge. Int J Mach Tools Manuf 65:41–46
Chung K, Ma N, Park T, Kim D, Yoo D, Kim C (2011) A modified damage model for advanced high strength steel sheets. Int J Plast 27:1485–1511
Yu S, Xie XL, Zhang J, Zhao J (2007) Ductile fracture modeling of initiation and propagation in sheet-metal blanking processes. J Mater Process Technol 187–188:169–172
Lemialea V, Chambert J, Picart P (2009) Description of numerical techniques with the aim of predicting the sheet metal blanking process by FEM simulation. J Mater Process Technol 209:2723–2734
Taupin E, Breitling J, Wu WT, Altan T (1996) Material fracture and burr formation in blanking results of FEM simulations and comparison with experiments. J Mater Process Technol 59:68–78
Komori K (2001) Simulation of shearing by node separation method. Comput Struct 79:197–207
Mediavilla J, Peerlings RHJ, Geers MGD (2006) An integrated continuous-discontinuous approach towards damage engineering in sheet metal forming processes. Eng Fract Mech 73:895–916
Mori K, Saito S, Maki S (2008) Warm and hot punching of ultra high strength steel sheet. Ann CIRP 57:321–324
Taylan A, Tekkaya AE (2012) Sheet metal forming—processes and applications: hot stamping. ASM International. 133–156
McAdams WH (1954) Heat transmission, 3rd edn. McGraw Hill, New York
Sellers L (1996) Proc. of 2nd Int. Conf. Modeling of Metals Rolling Processes, The Institute of Materials, London
Liu HS, Yang YY, Yu ZZ (2009) The application of a ductile fracture criterion to the prediction of the forming limit of sheet metals. J Mater Process Technol 29:5443–5447
Hambli R, Reszaka M (2002) Fracture criteria identification using an inverse technique method and blanking experiment. Int J Mech Sci 44:1349–1361
Wierzbicki T, Bao YB, Lee YW, Bai YL (2005) Calibration and evaluation of seven fracture models. Int J Mech Sci 47:719–743
Rice JR, Tracey DM (1969) On the ductile enlargement of voids in triaxial stress fields. J Mech Phys Solids 17:201–217
Ayada M, Higashino T, Mori K (1984) Central bursting in extrusion of inhomogeneous materials. In: Proceedings of the First ICTP. Adv. Technol. of Plast. 1:553–558
Liu HS, Fu MW (2014) Prediction and analysis of ductile fracture in sheet metal forming—part II: application of the modified Ayada criterion. Int J Damage Mech. doi:10.1177/1056789514535231
Liu HS, FU MW (2014) Prediction and analysis of ductile fracture in sheet metal forming—part I: a modified Ayada criterion. Int J Damage Mech. doi:10.1177/1056789514535231
Shapiro B. Using LS-DYNA for hot stamping. 7th European LS-DYNA Conference. 14th–15th of May 2009, Salzburg, Austria
Merklein M, Lechler J (2008) Determination of material and process characteristics for hot stamping process of quenchable ultra high strength steels with respect to a FE-based Process Design. SAE International, SAE Technical Paper Series.
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
About this article
Cite this article
Liu, H., Lei, C. Local heating-aided hot blanking of quenched ultra-high-strength steel BR1500HS. Int J Adv Manuf Technol 77, 629–641 (2015). https://doi.org/10.1007/s00170-014-6479-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00170-014-6479-y