What does decarburization mean during the heating process of forgings?

    There are many things to pay attention to when forging, but not every one should be strictly observed. What does decarburization mean during the heating process of forging? The following article mainly tells you about it.
    During heating, the carbon on the surface of the steel material reacts with certain oxidizing gases in the furnace gas, resulting in a decrease in the surface and carbon content of the steel material, which is called decarburization. Decarburization is also the result of Diffusion. On the one hand, the oxygen in the furnace gas diffuses into the steel, and on the other hand, the carbon in the furnace gas diffuses outward, so that a decarburized layer with low carbon content is formed on the steel surface. From the entire process, the decarburization layer can only be formed when the decarburization rate exceeds the oxidation rate. The factors that affect decarburization, like oxidation, are mainly influenced by factors such as the chemical composition of the steel, furnace gas composition, heating temperature, and heating time.
    The higher the carbon content of steel, the greater the tendency for decarburization. Some alloying elements increase the tendency for decarburization, such as c, w, Si, A1, etc. Some alloy elements can prevent decarburization, such as Cr, Mn, etc. Ni and V have little effect on decarbonization. The medium with the strongest decarbonization ability in the furnace gas composition is water vapor, followed by CO2 and 02, and finally H2. Increasing the amount of CO can reduce the decarbonization tendency. Heating in neutral or weakly oxidizing media can reduce the tendency for decarbonization. The higher the heating temperature and the longer the heating time, the more severe the decarburization. When the heating temperature is greater than 1000 ℃, the decarbonization effect is weak due to strong oxidation. At higher temperatures, decarburization will occur violently due to the loss of protective effect due to the detachment of oxide skin.