The phenomenon in which the iron and alloy on the surface of the material steel react with elements such as oxygen, carbon dioxide, and water vapor in the medium to form an oxide film during the heating process of aluminum alloy forging is called oxidation. The dimensional accuracy and surface brightness of high-temperature workpieces deteriorate after oxidation, and steel parts with poor hardenability of oxide films are prone to quenching soft spots.
Measures to prevent oxidation and reduce decarburization in aluminum alloy forging include:
1. Surface coating of the workpiece, sealed and heated with stainless steel foil packaging.
2. Heating is done using a salt bath furnace.
3. Use protective atmosphere heating.
4. Using a flame burning furnace.
When the raw material is heated during the forging process of aluminum alloy, the surface carbon reacts with oxygen, hydrogen, carbon dioxide, and water vapor in the medium, reducing the concentration of surface carbon, which is called decarburization. After quenching, the surface hardness, fatigue strength, and wear resistance of decarburized steel decrease, and residual tensile stress is formed on the surface, which can easily form surface network cracks.