Inverse estimation of transient temperature distribution in the end quenching test

摘要

End quenching is a simple test applied to engineering materials to determine their mechanical characteristics under normal heat treatment. The work reported here is part of a large programme aimed at the prediction of the thermal stress and strain generated during the quenching of low-alloy steel components. It is very difficult to obtain the temperature history or cooling rate on the surface of the specimen under quenching. The estimation scheme of the temperature history proposed here was used to generate the relationship of the cooling rate with the mechanical properties of the materials for most thermal processes. The aim of this work is to calculate the heat flux and temperature distribution of the quenching surface, where the temperatures arenot easy to measure during quenching. This study proposed an inverse prediction scheme with the finite-element method. The interior temperature near to the quenching surface was measured by a thermocouple and provided the input date for the inverseestimation of the unknown thermal boundaries in the heat-conduction problem of the quenching specimen. An accurate improve the estimation of the heat dissipation of the quenching surface has been achieved. Here the conjugate gradient method is used toimprove the estimation of the distribution of the surface temperature and heat flux for a 2D cylindrical co-ordinate problem .