Improved gas blowing program in AOD stainless steelmaking

The AOD process yields excellent quality stainless steel, but, at the same time, the consumption of input materials, such as silicon, lime and gases varies considerably, also during seemingly identical conditions. The predictability of the process is therefore decreased. The conventional gas blowing program and some unconventional ones are surveyed. An improved gas blowing program is described, together with tests in full-scale AOD operation. According to the improved gas blowing program, the oxygen and the inert gas are not blown pre-mixed in certain ratios, but, instead, separated one at a time. Test results show lower consumption of input materials, higher productivity and increased predictability. (C) Munksgaard, 1998.