Rough Bar Heating System Introduced at Hot Strip Mill
Rough bar heating system at the Fukuyama Works'No.2 hot strip mill
A new heating system specially developed for rough bars (roughly rolled slabs that will enter a finishing mill) recently went into operation at the Fukuyama Works' No.2 hot strip mill. The new heating system is designed to improve the quality of hot coil for light gauge (lmm thick) and high-tensile strength (590-780 Mpa) steel sheets while expanding the product size, in order to encourage development of new sheet products with higher formability and better surface conditions for auto-motive applications. NKK is the first steelmaker in the world to introduce this kind of on-line rapid heating system to hot strip mill operations. The new 5.5m long Toshiba-made heating system employs large-capacity (24,000 kilowatts of electricity) tunnel-shaped induction heating solenoid coils, through which rough bars are rapidly heated (by more than 100°C) throughout their length and width as they pass prior to entering the finishing mill. The heater's unique feature is the use of NKK's 6.5%-silicon magnetic steel sheet (NK Super-E Core) for the cores of the induction heating coils for higher heating efficiency with reduced noise due to the steel's excellent magnetic properties. The new heating system offers the following advantages:
NKK plans to introduce the same heating system at its other hot strip mill. |
