The typical temperature measurement curves inside the mold at positions 2 and 3 are shown in Fig. 1 and 2. Position 2 is the temperature measurement point at the center of the casting, and position 3 is the farthest temperature measurement point from the center, that is, the closest temperature measurement point to the cavity wall. The temperature measurement curves at positions 2 and 3 are labeled TA2 respectively_ 1、TA2_ 2、TB2_ 1、TC2_ 1、TC2_ 2 and TA3_ 1、TA3_ 2、TB3_ 1、TC3_ 1、TC3_ 2。 Take TA2 as an example_ 1 as an example, the letter T represents the thermocouple for temperature measurement, the letter a represents the distance from the temperature measurement position of the thermocouple head to the end face of the temperature measurement unit, the number 2 represents the position 2, and the number 1 represents one of the symmetrically arranged thermocouples. These temperatures were measured under the conditions of applied pressure of 70 MPa, pouring temperature of 660 ℃ and initial mold temperature of 230 ℃.
As shown in Figures 1 and 2, during the experiment, the pouring time is marked as O. At this moment, high temperature aluminum alloy melt is poured into the die cavity. At the beginning, the mold temperature increases sharply, and then the heating rate decreases gradually. At 9s, an applied pressure of 70MPa was applied to the casting. At the moment when the applied pressure is applied, the temperature of TA2 and TA3 rises sharply, and the temperature of other temperature measuring points also rises, but it is relatively gentle. When the temperature reached the maximum, it began to decrease gradually.
As shown in Figure 1, two symmetrically placed thermocouples (TA2) are arranged at 1 mm at position 2_ 1 and TA2_ 2) And two symmetrically placed thermocouples (TC2) at 6 mm_ 1 and TC2_ 2) The maximum difference of temperature is 4 ℃ and 6 ℃ respectively.
As shown in Figures 1 and 2, after the temperature reaches the maximum, the temperature at position 3 decreases more rapidly than that at position 2. This is because position 3 is close to the cavity wall, and the heat transfer perpendicular to the cavity surface has a great influence on position 3. In addition, the external pressure also strengthens the effect. However, as shown in Figure 2, two symmetrically placed thermocouples (TA3) are arranged at 1 mm at position 3_ 1 and TA3_ 2) And two symmetrically placed thermocouples (TC3) at 6 mm_ 1 and TC3_ 2) The maximum difference of temperature is 10 ℃ and 15 ℃ respectively. The maximum temperature difference is 15 ℃ and the error is (ttc3)_ 1-TTC3_ 2)/ TTC3_ 1) 9%. This shows that the one-dimensional heat transfer assumption is reasonable.