Direct Contact Heating for Hot Forming Die Quenching

2014 ◽  
Author(s):  
J. N. Rasera ◽  
K. J. Daun ◽  
M. D’Souza
Keyword(s):  
Yield Strength ◽  
Material Characterization ◽  
Direct Contact ◽  
Hot Forming ◽  
Boron Steel ◽  
Martensitic Structure ◽  
Austenitizing Temperature ◽  
Contact Heating ◽  
Heating Technology ◽  
Roller Hearth

Most hot forming lines use slow, energy-intensive roller hearth furnaces to austenitize boron steel “blanks”. This paper describes an alternative heating technology in which blanks are austenitized by bringing them into contact with a hot monolith. The austenitizing temperature was reached in less than 30 seconds, and subsequent material characterization tests on oil-quenched blanks confirm that a fully martensitic structure is formed, and that the hardness and yield strength are comparable to furnace-treated samples. An Al-Si coating is typically used to prevent the oxidation and decarburization of the blanks within the furnace; preliminary tests found that the coating adheres to the monolith, impeding blank transfer and damaging the Al-Si-Fe ternary coating. Five interchangeable striking surfaces were assessed to see if they were less prone to adhering to the molten Al-Si coating.

Direct contact heating for hot forming die quenching

2016 ◽  
Vol 98 ◽  
pp. 1165-1173 ◽  
Author(s):  
J.N. Rasera ◽  
K.J. Daun ◽  
C.J. Shi ◽  
M. D'Souza
Keyword(s):  
Direct Contact ◽  
Hot Forming ◽  
Die Quenching ◽  
Contact Heating

Tailoring by Direct Contact Heating During Hot Forming/Die Quenching

2019 ◽  
Vol 50 (8) ◽  
pp. 3705-3713
Author(s):  
Natalie N. Field ◽  
Massimo Di Ciano ◽  
Adrian P. Gerlich ◽  
Kyle J. Daun
Keyword(s):  
Direct Contact ◽  
Hot Forming ◽  
Die Quenching ◽  
Contact Heating

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

Forming Response of Ultra High Strength Steel Sheet to Stamping Speed during Hot Forming

2010 ◽  
Vol 160-162 ◽  
pp. 123-129 ◽  
Author(s):  
Hai Yan Yu ◽  
Li Bao ◽  
You Zhi Deng ◽  
Wei Cao
Keyword(s):  
Temperature Field ◽  
Steel Sheet ◽  
Coupling Effect ◽  
High Strength ◽  
Hot Forming ◽  
Boron Steel ◽  
Cold Forming ◽  
22Mnb5 Steel ◽  
Ultra High Strength Steel ◽  
Shaped Part

Stamping speed is an important parameter in sheet metal forming especially in hot forming. In this study, hot forming of a U-shaped part made of ultra high strength boron steel (22MnB5) sheet is simulated with solid elements. The mechanical properties of 22MnB5 steel sheet and the key process parameters are introduced in detail. Emphasis is laid on the forming response of the boron steel sheet to stamping speeds of 3.25m/s, 0.325m/s and 0.0325m/s. The mechanism of stamping speed acting on hot formability and temperature field of the stamped part is analyzed. It is demonstrated that stamping speed affects both formability and the heat transferred from blank to tools and to environment during hot forming. And the coupling effect of material properties, the heat produced during plastic deformation and heat boundary condition decides the formability and temperature field. An appropriate stamping speed is more important for hot forming than that for common cold forming.

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.

Influence of Annealing Temperature on Microstructure and Properties of the Hot-Stamping Boron Steel

2012 ◽  
Vol 602-604 ◽  
pp. 385-389
Author(s):  
Kuan Hui Hu ◽  
Xiang Dong Liu ◽  
De Xin Tian ◽  
Guan Wen Feng ◽  
Fang Yi Sun
Keyword(s):  
Yield Strength ◽  
Annealing Temperature ◽  
Hot Stamping ◽  
Phase Region ◽  
Boron Steel ◽  
Two Phase ◽  
Microstructure And Properties ◽  
Significant Downward Trend ◽  
Test Steel ◽  
Higher Temperature

The effect of different annealing temperature on microstructure and properties of the hot-stamping boron steel were studied.The results show that the yield strength of the test steel is reduced with increasing annealing temperature, only at 790°C,the specimen yield strength increased slightly, and showed a significant downward trend after 790°C.The specimen tensile strength and hardness with the change of the same trend when annealing temperature changes.And through the test we can see,at 760°C ,the test steel has entered a two-phase region,the test steel gain ferrite and pearlite when it is annealed below the temperature,it is easy to appear martensite microstructure when it is annealed in the higher temperature,and lead to the strength and hardness of the rise.

scholarly journals Minimizing the Cycle Time of a Roller Hearth Furnace for Hot-Forming Die-Quenching

2018 ◽  
Vol 418 ◽  
pp. 012016
Author(s):  
Mohit Verma ◽  
Massimo Di Ciano ◽  
J. Richard Culham ◽  
Cyrus Yau ◽  
Kyle J. Daun
Keyword(s):  
Cycle Time ◽  
Hot Forming ◽  
Hearth Furnace ◽  
Die Quenching ◽  
Roller Hearth

Direct Contact Heating of Fermentors by Rotational Hot Gas Discharge System

2002 ◽  
Author(s):  
Yutaka Kitamura ◽  
Tung Liang ◽  
Dan Paquin ◽  
Loren Gautz
Keyword(s):  
Direct Contact ◽  
Gas Discharge ◽  
Discharge System ◽  
Hot Gas ◽  
Contact Heating
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