In the numerical simulation of solidification process of sand castings, the thermophysical parameters of the mold are one of the important factors affecting the simulation accuracy. Although the thermophysical properties of various molding sands and molds have been studied before, the test results can not be directly compared due to different methods, different pouring metals, different raw sand composition and ratio and inconsistent test conditions. The pouring method comprehensively considers many influencing factors under the actual sand casting conditions, which is the closest to the actual sand casting conditions, so the thermophysical property value obtained is also the most accurate. Its basic idea is to measure the temperature change of the mold after liquid metal pouring, and determine the thermophysical property value of the mold through the treatment of the measured temperature curve.
The test sand sample is glass quartz sand used for molding in actual sand casting. The test is carried out by pouring molten metal under the condition of one-dimensional heat conduction. The temperature curves of sand castings and several points in the sand mold are obtained by testing, and then the inverse algorithm is used to solve the thermophysical parameters of the sand mold, i.e. specific heat capacity and thermal conductivity, so as to provide reliable thermophysical parameter data for numerical simulation research.
Aiming at the glass quartz sand mold used in actual sand casting production, the thermophysical parameters were measured by self-designed test scheme. The main contents are as follows:
- Based on the basic principle of pouring method, a test scheme is designed for water glass quartz sand mold. The purpose of this test is summarized. On this basis, considering various influencing factors, an appropriate test scheme of thermophysical parameters is designed.
- The relevant materials and testing instruments used in the test are introduced. The models and relevant parameters of thermocouple, temperature inspection instrument and quartz sand mold used in the test are introduced in detail, and the test process is briefly introduced. After the test, the test data are processed and the test results are output.
- The mathematical model of the inverse algorithm of sand mold thermophysical property test is described. The specific heat capacity and thermal conductivity of water glass quartz sand mold are calculated by using the temperature data measured after the test, and the thermophysical parameters of simulated water glass quartz sand mold are obtained.