Title: Determination of heat transfer coefficient during high-speed water quenching

Authors: Thomas Lübben; Jochen Rath; Fabian Krause; Franz Hoffmann; Udo Fritsching; Hans-Werner Zoch

Addresses: Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany. ' Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany. ' Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany. ' Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany. ' Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany. ' Stiftung Institut für Werkstofftechnik IWT, Badgasteiner Str. 3, 28359 Bremen, Germany

Abstract: According to literature, rapid water quenching can create compressive residual stresses near the surface even in through-hardening steel grades and can hereby lead to a significant increase of the fatigue-limit. But, there is a lack in understanding the mechanisms and limitations of high speed quenching. Therefore, a new quenching facility was constructed to characterise such quenching processes. One of the first steps was the determination of heat transfer coefficients (HTC) in such a facility. This parameter is necessary to characterise and to simulate a quenching process. In this paper the experimental determination of HTC, and the results of flow field and HTC calculation by use of CFD will be presented. A comparison of measurements and simulations shows a systematic discrepancy, which must be explained by (a) systematical error(s) in the experimental estimation method of HTC and may be due to the complexity of the applied turbulent mass and heat transfer models.

Keywords: high-speed water quenching; intensive quenching; cooling curve measurement; heat transfer coefficients; HTC; convective heat transfer; flow field simulation; CFD; computational fluid dynamics.

DOI: 10.1504/IJMMP.2012.047494

International Journal of Microstructure and Materials Properties, 2012 Vol.7 No.2/3, pp.106 - 124

Available online: 24 Jun 2012 *

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