Vacuum, decarburization, reduction and desulfurization. The evacuation stage includes alloying, denitrification and chemical heating. The decarburization stage is divided into two parts: forced decarburization and natural decarburization. The final stage includes feeding, reducing and desulfurization in two parts.
Stainless steel flange vacuum alloying
If the initial chromium and manganese content and the target value of the difference is not large, you can oxygen in the ladle into the high carbon and carbon alloy. The use of cheap alloys to replace the expensive (low carbon) alloy after vacuum treatment can reduce the refining costs.
For ordinary steel (eg AISI304), in order to reduce the consumption of argon, AOD converter blowing nitrogen throughout the process, so rkflange initial nitrogen content will be high (≥ 1500ppm), so before the oxygen must be denitrified. In general, for denitrification, all air pumps should be opened to ensure that the vacuum pressure is below 0.2 kPa and the argon blowing rate is controlled at medium speed.
Denitrification and alloying may cause the temperature to be too low to decarburize, so chemical heating is required. By adding a small amount of aluminum can be achieved chemical heating, but the amount of aluminum should be added less than 0.15% of the weight of molten steel, otherwise it will be difficult to obtain pure molten steel.
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