Iron-chromium alloys of substantial chromium content, such as stainless steel containing 12% or more chromium, are commonly made in a direct-arc electric arc furnace.
Steel scrap is charged in the furnace hearth, the arc is struck and as soon as the arc is below the top scrap level, melt-down of the scrap is initiated under the maximum useful electric power. The scrap rapidly proceeds to melt, but as soon as melt-down proceeds to a degree where the arc energy is no longer adequately absorbed by unmelted scrap, power must be reduced to prevent the arc radiation from causing rapid deterioration of the furnace side wall and roof. After melt-down, ferro-chromium is added to the melt to obtain the required chromium content.
It is desirable to obtain a faster melt-down and eliminate the need for ferro-chromium which is a relatively expensive additive.
The cost of making such alloys would be reduced if the melt-down could proceed at a faster rate and the use of ferro-chromium eliminated.