Experimental investigation of heat transfer characteristics during water jet impingement cooling of a high-temperature steel surface

ABSTRACT

The microstructure and mechanical properties of the hot rolled steel depend on the laminar jet cooling control on the runout table. An experimental and numerical study of the heat transfer during water jet impingement cooling of a hot steel plate (600 to 900°C) is presented. The effects of plate temperature upon the heat transfer were analyzed by the inverse heat conduction method that provided the heat fluxes on top surface from measured temperatures into the plate. Rewetting (liquid-solid contact) occurs on surface above 880°C. Higher initial temperatures enlarge the heat flux, but delay the onset of the rewetting and the advance of rewetting front radius (R_wet). Heat transfer coefficient (HTC) increases as surface temperature decreases. The size of the non-symmetric effective jet cooling zone depends on strip speed. Correlations to predict HTC and Rwet have been proposed. Results will contribute for enhancement of fast cooling system in hot strip mill.

KEYWORDS:

• Hot steel rolling mill
• steel temperature control
• jet impingement cooling
• heat transfer
• accelerated cooling system
• rewetting temperature
• inverse heat conduction method
• heat transfer coefficient
• effective cooling zone
• water jet cooling

Acknowledgements

Authors acknowledge the support from Usiminas Steel.

Disclosure statement

No potential conflict of interest was reported by the author(s).