Because the characteristic of squeeze casting is that the high temperature melt solidifies under the external pressure, many experiments will be carried out under different external pressure in each working condition. The selection of the applied pressure is mainly based on the range of the press. The punch forces of 30t, 60t and 90t are selected, and the corresponding pressures acting on the surface of the casting are 23mpa, 46MPA and 70MPa.
For the pouring temperature, in the experimental study, before pouring, an armored thermocouple prepared in advance is inserted into the aluminum alloy melt to measure the melt temperature, and the temperature measurement is maintained before pouring. In this way, the pouring temperature can be determined at any time by measuring the temperature in real time, and the thermocouple is taken out before pouring, and the temperature at this time is taken as the pouring temperature. In the experiment, the pouring temperature is 660 ℃, 700 ℃ and 720 ℃.
For the initial temperature of the mold, in this experimental study, each time the casting is taken out, the mold temperature decreases rapidly. When the temperature of each thermocouple in the temperature measurement unit is basically the same, and the cooling rate is less than 2 ℃ / min At this time, the mold temperature changes little, so the next squeeze casting experiment can be carried out. Through the real-time monitoring of the temperature measurement unit, the experiment can be started when the mold temperature drops to the set temperature, and the temperature at this time is the initial temperature of the mold. In the experimental study, the initial temperature of the die is 190 ℃, 250 ℃ and 300 ℃.
In order to study the influence of different process parameters on the interface heat transfer, the experimental conditions were established for the above three process parameters, and repeated experiments were carried out for each condition to ensure the accuracy of the experimental data.
The coating used is water-based graphite. Tt260b coating thickness gauge was used to measure the coating thickness. Because the coating is sprayed directly to the surface of the mold cavity during the experiment, the coating thickness can not be accurately controlled. In the study, the coating thickness values of each experiment were recorded, and the variation range of coating thickness is 0-186 μ M.