Why do casting parts have air holes?
There are many reasons for casting porosity, mainly due to:1. smelting process is unreasonable, metal liquid absorbs more gas;2. the gas in the mold invades the metal liquid;3. from the mold is more water brush, core dry;4. the casting has poor ventilation;5. ladle tools are not dry.Wait。
First, from the source, tools, raw material drying, in the process of melting into the reaction gas, another influence is pouring process, such as high temperature solidification gas dissolved too much after not excluded. The method can adjust the pouring temperature properly, control the source of gas (drying and controlling the inoculant, especially the content of magnesium), and add cooling iron to change the solidification mode. It depends on what kind of casting you are. You can't make it clear at once. And molding sand relationship is mainly water content and permeability, brush coating resin content.
Cangshan Qiao hidden his answer is quite comprehensive, you can try using inert gas to reduce air cover