North American Stainless (NAS) contracted SMS group for the supply of a bright annealing line. NAS is building a high-performance production facility for bright-annealed stainless steel strip in Ghent, Ky. The line will include an electrically powered vertical furnace from Drever, a company of SMS group. At approximately 220 kilowatt hours per ton, the furnace’s energy consumption is 60% lower than a conventional design with a muffle furnace. The high efficiency is achieved by direct heating via electrical heating elements and dynamic annealing at up to 1250°C (2282°F).
The annealing process takes place in a pressurized inert atmosphere (up to 90% hydrogen), which ensures a low dew point and produces an immaculately reflective surface. The total furnace construction is made gas tight. Special sealing elements at the entry and exit minimize losses.
The output capacity of NAS’ plant, which will manufacture both austenitic and ferritic grades, will amount to 95,000 tons per year. Commissioning will take place in early 2017.