Experimental and Simulation Study for Heat Transfer Coefficient in Hot Stamping of High-Strength Boron Steel

2015 ◽  
Vol 46 (6) ◽  
pp. 2419-2422 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Peng Gao ◽  
Chaoyang Liu ◽  
Xiangji Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Simulation Study ◽  
Hot Stamping ◽  
High Strength ◽  
Boron Steel

High Temperature Heat Transfer During Hot Forming Die Quenching of Boron Steel

2013 ◽  
Author(s):  
Etienne Caron ◽  
Kyle J. Daun ◽  
Mary A. Wells
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling Rate ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Steel Blank ◽  
Die Quenching

Distributed mechanical properties can be obtained in ultra high strength steel parts formed via hot forming die quenching (HFDQ) by controlling the cooling rate and microstructure evolution during the quenching step. HFDQ experiments with variable cooling rates were conducted by quenching Usibor® 1500P boron steel blanks between dies pre-heated up to 600°C. The heat transfer coefficient (HTC) at the blank / die interface, which is used to determine the blank cooling rate, was evaluated via inverse heat conduction analysis. The HTC was found to increase with die temperature and stamping pressure. This heat transfer coefficient increase was attributed to macroscopic flattening of the boron steel blank as well as microscopic deformation of surface roughness peaks. At the end of the hot stamping process, the HTC reached a pressure-dependent steady-state value between 4320 and 7860 W/m2·K when the blank and die temperatures equalize.

Characterization of Heat Transfer Coefficients of Tool Materials and Tool Coatings for Hot Stamping of Boron-Manganese Steels

2010 ◽  
Vol 438 ◽  
pp. 81-88 ◽  
Author(s):  
Michael Wieland ◽  
Marion Merklein
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Tool Steels ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Coated Tool

One characteristic of hot stamping of ultra high strength steels is the high wear rate of the used tools which leads to shorter tool life. Coatings improving wear resistance can increase the lifetime of the used tools but process relevant data such as the heat transfer capability of coated tool steels are missing. Within this paper the heat transfer capabilities of coated tool steels for the hot stamping processes are determined. Therefore different coating systems based on AlCrN are applied on the tool steels and the pressure dependent heat transfer coefficient is determined using process relevant conditions. As semi-finished blank the hot stamping steel 22MnB5 with an aluminum-silicon pre-coating is used. With respect to a finite element analysis of the forming operation of the hot stamping process the heat transfer coefficient represents an important input data for the process layout.

scholarly journals Measurement of Heat Transfer Coefficient of Boron Steel in Hot Stamping

2014 ◽  
Vol 81 ◽  
pp. 1750-1755 ◽  
Author(s):  
Tzu-Hao Hung ◽  
Pei-Wu Tsai ◽  
Fuh-Kuo Chen ◽  
Tyng-Bin Huang ◽  
Wei-Liang Liu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Hot Stamping ◽  
Boron Steel

Numerical Simulation and Optimization of Cooling Ducts Layout in Hot Stamping Die

2012 ◽  
Vol 184-185 ◽  
pp. 333-336 ◽  
Author(s):  
Hui Xie ◽  
Ya Ke Chen
Keyword(s):  
Heat Transfer ◽  
Hot Stamping ◽  
Cooling Water ◽  
High Strength ◽  
Bulk Flow ◽  
Boron Steel ◽  
Press Hardening ◽  
Simulation And Optimization ◽  
Stamping Die ◽  
Cooling Ducts

Abstract. As an innovative process of manufacturing ultra high strength steel (UHSS), hot stamping or press hardening is a multi-physical coupling process with complex changes in thermal, mechanical and phase transformation. In this work, in order to study heat transfer from workpiece to upper & lower die and cooling water, a new approach, named Bulk Flow, is adopted to model the cooling ducts and to simulate heat transfer in hot stamping die. Not only can tool design, cooling duct layout and process parameters be studied and optimized to increase the cooling rate and to homogenize temperature distribution in workpiece, but also, the precision of hot stamping simulation be improved. The experimental results of boron steel components formed by the designed die show that the martensite is homogenous. It indicates the feasibility of the bulk flow method．

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