Abstract
The C-O carbon vs. oxygen relations of extremely low carbon austenitic stainless steel and Ni-base alloy, in comparison with iron, were studied for the vacuum refined melts together with some thermodynamic considerations.
Sampling was made during the quiescent period of melts in a 200kg vacuum induction furnace with the MgO lining, and then the chemical compositions were determined.
During quiescent period after violent boiling the C-O relations in the stainless steels with C%≈0.01 were shown to be in equilibrium and the following relations were obtained.
Melt Temp. (°C)
Fe 1600
Austenitic
Stainless
steel
Ni base 1550
high alloy
Calculated values of PCO for the iron melts were about 10times higher than those for stainless steels. It is considered that the effect of refractory on the oxygen potential of molten steel depends on accompanying elements.
For the Ni base high alloys it was found that the C-O relation was similat to those for steel and the efficiency of deoxidizer added at tapping was greater than those for steels.
