Also active for Wisco, we supplied two furnaces for new flattening and coating lines in China. These lines are used to enhance the production of HGO grades. They come with an annual production capacity of some 180,000 t. Both furnaces were successfully commissioned in 2012.
The two furnaces operated continuously for the first five months after start-up. During this time, they produced grades including HGO materials in low-temperature mode. The furnaces feature new technologies for thermal flattening as well as cooling which improve surface quality and process control.
Straight after commissioning, Wisco added 180,000 tpy to its production capacity of grain-oriented (GO) silicon steel strip, also known as electrical steel strip, including high-permeable grades (HiB). The material, with a silicon content of up to 3.5 percent, is mainly used in high-performance transformers.
It's the job of the two furnaces to apply an insulating layer, then dry the strip. That sets the surface tension. Another benefit of thermal flattening is better strip evenness. The furnace atmosphere consists of 95 percent nitrogen and 5 percent hydrogen.