Precision casting belongs to the specialty of thermal processing. Therefore, temperature is a very important factor that affects casting, and it is also an important parameter that needs to be controlled during the casting process. In our college days, there was a course called Casting Temperature Measurement Technology, which specifically explained various temperature control in the casting process. As a casting practitioner or a practitioner related to casting, you still need to understand some casting temperature control techniques.

Most casting methods are hot mold casting. There are metal molds, plaster molds, ceramic molds, etc. Talking about metal molds, such as: metal molds, die-casting molds, because metal molds have large heat storage capacity and good chilling effect, therefore, the mold must be preheated before the molten metal enters the mold, otherwise, it may cause castings to be poured Insufficiency, cold barrier and other defects. Therefore, in the production of metal molds and die-casting, mold temperature will be a parameter that casting engineers need to control. And it must be noted in the process documentation. However, no measurement is necessary. In the production of general aluminum alloy metal molds and die-casting, the mold should be heated for a period of time before use to increase the mold temperature to a certain range. For example, the metal type is generally between 200°C and 300°C. Whether the mold temperature is appropriate depends mainly on the grasp of the on-site workers. One is time control, and the other is mold testing. Generally, on-site workers will try pouring and check the appearance of the casting after pouring. If the appearance of the casting meets the quality requirements of the casting, it is considered appropriate to preheat the mold. In addition, some units also use trial casting to preheat the mold, which is a waste of more liquid. Some people may think that this is the rest of the metal, no one of you thinks, you will not say, this is a long time, you have not controlled the mold temperature! As the temperature increases, the probability of shrinkage cavity will greatly increase, and the crystal grains will also become coarser. Although this control is passive. Of course, there is also active control: mold plus cooling water. Don't talk about casting, just wax molds. When the mold becomes hot, it should be cooled in cooling water to control the temperature of the mold.

The temperature control of the mold shell in investment casting is also a truth, but it is more accurate. Generally use electric furnace or natural gas furnace. Hot air furnace is used for high temperature, electric furnace is used for low temperature. In contrast, the temperature of the investment casting mold shell is more accurate than that of the metal mold.