Calculation of Kobasko's Simplified Heat Transfer Coefficients from Cooling Curve Data Obtained with Small Probes

Abstract

Although heat transfer coefficient characterization of quench severity is not new, there continues to be a need for the rapid and relatively simple calculation of heat transfer coefficients from time-temperature cooling curve data files obtained via test methods such as ASTM D6200, D6482, D6549, and D7646, which utilize relatively small cylindrical test probes with diameters of ≤12.5 mm. One method that may be readily used is Kobasko’s computational method for effective heat transfer coefficients, which is based on time-temperature data obtained at the geometric center of small test probes during cooling curve analysis. A description of the step-by-step procedure for performing these calculations on actual experimental data is provided here.