Gravity casting is a casting process widely used in the metal processing industry, especially in the production of aluminum and copper alloys. However, in this process, the generation of gas in the mold may pose a serious threat to production safety. This article will explore the sources of gas generation and its impact on the safety of gravity casting.

Sources of gas generation
In the gravity casting process, the generation of gas mainly comes from the following aspects:
Volatilization of liquid metal: Under high-temperature smelting conditions, liquid metal may release gas. For example, aluminum alloy releases hydrogen when it melts. These gases not only affect the physical and chemical properties of the casting, but may also accumulate in the mold, forming a potential safety hazard.
Decomposition of mold materials: Some mold materials will undergo thermal decomposition in a high-temperature environment and release gas. The generation of this gas may cause the strength of the mold to decrease, which in turn affects the overall safety of the casting process.
The impact of environmental humidity: The humidity in the casting environment will quickly convert into water vapor after contacting the molten metal, thereby increasing the gas pressure in the mold. This increase in pressure may cause the mold to fail.
Chemical reaction: During the melting process, chemical reactions may occur between different metals or alloys, releasing gas. These reactions not only speed up the generation of gas, but also increase the safety risks in the production process.

Direct impact of gas on safety
The generation of gas in the gravity casting mold has many effects on the safety of the gravity casting process, mainly including the following aspects:
Explosion risk: Gas in the mold, especially hydrogen and other flammable gases, may cause explosions under high temperature conditions. If the accumulation of gas in the mold is not discharged in time, it will cause a sharp increase in pressure and form an explosion hazard. Especially in a confined space, the accumulation of gas is more likely to cause violent reactions and cause serious safety accidents.
Release of toxic gases: Some casting materials release toxic gases such as carbon monoxide and nitrogen oxides at high temperatures. These gases not only pose a threat to the health of operators, but may also cause poisoning accidents. During the casting process, if the ventilation is poor or the exhaust system is not designed reasonably, the concentration of toxic gases may rise rapidly, thereby increasing safety hazards.
Mold failure: The generation of gas may lead to a decrease in mold strength. Under high temperature conditions, the increase in gas pressure may cause deformation or rupture of the mold material, affecting the normal use of the mold. This failure not only causes casting quality problems, but may also cause the mold to fly out during the casting process, endangering the safety of the operator.
Operator safety: During the gravity casting process, operators face multiple safety risks. The generation of gas may cause equipment failure or accidents, posing a threat to operator safety. For example, the accumulation of gas in the mold may cause sudden failure of the equipment, resulting in operator injury.