Measured temperature field data of flat sand castings

The temperature data measured in the solidification process experiment is the basis for solving the interface back calculation. Therefore, it is necessary to sort out the temperature field data at the thermocouple in several groups of temperature measurement tests. The temperature test data are the temperature data of the first 6000s and the later stage. In the pouring experiment, the temperature data at the thermocouple are selected as follows; In the pouring experiment of flat sand castings, because the thermocouple positions on both sides are symmetrical, we choose the thermocouple at No. 1, 2, 3 and 4 on the right side with more stable data as the experimental data, which is used as the basic data for reverse calculation of interface heat flow and interface heat transfer coefficient of flat parts. The measured temperature of flat sand mold is shown in the temperature measurement diagram.

As shown in the figure, the test temperature curve of thermocouple with time in the temperature measurement test of 50mm thick ZL101 Aluminum alloy plate. Tc1 represents the interface temperature of sand mold at the casting / sand mold interface, and TC2, TC3 and TC4 are the internal thermocouple temperature of sand mold 6mm, 14mm and 22mm away from the casting / sand mold interface. The actual pouring temperature is about 705 ℃, the initial temperature of sand mold is 25 ℃, and the initial temperature of molten metal decreases sharply under the action of chilling. Tc1 can not see the actual temperature obviously. According to the change of Tc1 temperature, it can be seen that the solidification process of sand casting is divided into three intervals. Before 200s, the molten metal is in the overheating stage. The molten metal is greatly affected by the temperature difference of the mold, and the molten metal releases a lot of heat. The molten metal temperature drops sharply, while the sand mold temperature rises rapidly until the molten metal temperature reaches the end of the liquidus (TL). This stage is called the molten metal overheating zone; At 200s, the temperature of the molten metal reaches the liquidus, and the overheating of the molten metal is basically eliminated. At this time, the slope of the temperature drop curve of the sand casting decreases significantly, indicating the beginning of the solidification of the molten metal. During the period of 200-1750s, the temperature decreases continuously due to the change of the latent heat release rate. At 1750s, the temperature drops to the solidus ts, forming eutectic components for eutectic solidification, During 550-1300s, eutectic components are formed, and the latent heat is released to maintain the temperature at the solidus. This stage is called solidification zone. After about 2600s, the solidification process ends, the latent heat of the sand casting is completely released, and the overall temperature drop rate is accelerated, which is later called the cooling zone.

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