Vacuum Oxygen Decarburisation converter VODC for steel refining

10 Vacuum Oxygen Decarburisation converter (VODC) for steel refining 

The VODC (Vacuum Oxygen Decarburisation Converter) operates in such a way that molten steel is contained in the converter, which is attached to vacuum pumps, steam ejectors and an argon gas source. Two distinct processes are carried out in the vacuum treatment of stainless steel to obtain a higher quality level. 

the steel is decarburised by introducing oxygen into the melt. At the same time, some argon is injected from the converter base. The converter uses vacuiun pumps to lower the partial pressure of carbon monoxide, to such an extent that effective decarburisation can be carried out without oxidising too much of the chromium. This first process is similar to AOD decarburisation, but less argon is needed thanks to the lower total gas pressure and the process is much more efficient. The oxidised chromium is reduced back to liquid steel with aluminium. 

The VODC process provides specific steel qualities, which cannot be obtained by other methods. The total oxygen content is also lower than what is typical for electric arc melted and AOD-treated steel, because a high level of oxide inclusions are removed form the melt during the VODC process, and most of the dissolved oxygen is further removed during the degassing phase. 

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