INFLUENCE OF PROCESS PARAMETERS DURING WATER COOLING AT RUN-OUT TABLE

S. Sikdar and A. Mukhopadhayay

Keywords

Finite difference method, heat transfer coefficient, run-out table, hot strip mill, coiling temperature (CT), finish rolling temperature (FRT) List of symbols aa, ar Constant in (8)aw Constant in (8)c Specific heat, J/Kg-KCT Coiling temperature Bi Biot number (h ∗ ∆x/k)DD Deep drawing EDD Extra deep drawing Fo Fourier number (α∆t/(∆x)2)FRT Finish rolling temperature h Heat transfer coefficient, W/m2-Kha Heat transfer coefficient of air convection, W/m2-K * R&D and SS Division

Abstract

A model is developed to obtain the coiling temperature and the cooling rate of strip cooled at the run-out table (ROT) of the hot strip mill (HSM), which are important parameters for the metallurgical structure of the hot band finally produced in HSM. The authors analyze in detail the sensitivity of the coiling temperature (CT) vis-à-vis cooling rate due to the variation of several key parameters, such as mill speed, strip thickness, finish rolling temperature (FRT), efficiency of macro-header for cooling, and efficiency of micro-header for cooling. For analysis, steel strips of low carbon grades such as D, EDD, and DD in the thickness range of 2 to 6 mm are considered.

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