engleski

Calculation and Measurement of the Workpiece's Surface Temperature During Quenching

It is of great importance to know the temperature-lime history on the very surface of the workpiece during quenching, in order to be able to calculate relevant heat transfer coefficients, cooling curves inside the workpiece, and predict structure transformations, stresses and resulting hardness. The quenching process in evaporable liquids results with highly non-stationary heat transfer on the workpiece surface, and very steep spatial temperature gradients within the workpiece. The paper discusses comparison between estimation and measurement of the surface temperature on a stainless steel AISI-304 cylinder 50 mm Dia x 200 mm quenched in oil and in a PAG polymer solution. Assuming radially symetrical heat flow at half-length cross-section a 1-D inverse heat conduction code was used to estimate surface conditions, based on temperature data measured at 1.5 mm below the surface of the cylinder. Surface temperature was measured with a special eroding (self-renewing) thermocouple according to U.S.Pat No 2,829.185.

heat treatment of steels; quenching; measurement of the surface temperature; calculation of temperature

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