The Continuous Mill Technology (CMT™) combines conventional gas- or oil-fired furnaces with an inline the Elo-Long induction heater between continuous casting and the rolling line. The billet’s residual casting heat is used directly for rolling, requiring only temperature equalisation and adjustment to the optimal rolling temperature. This reduces energy consumption compared with reheating billets from ambient or intermediate temperatures. Operating costs are lowered through reduced energy use, higher yield, elimination of billet storage, and less maintenance and operating staff. Unlike conventional minimills, induction heating in a CMT™ minimill eliminates direct CO2, NOx and SOx emissions. In a conventional minimill producing about 800,000 tonnes per year, emissions can reach around 53,000 tonnes of CO2.

Customer challenges addressed

  • High power density up to 2.5 MW per coil.
  • Restores billets from ~980–1,000 °C to 1,100–1,130 °C.
  • Limits head‑to‑tail temperature difference to ≤5 °C.
  • Controls consecutive‑billet ΔT in the 0–25 °C range.
  • Continuous digital control and extensive diagnostics.
  • Zero NOx emissions and reduced scale formation.
  • Maintains cos φ ≥ 0.95 for stable electrical operation.

Key features

Homogenisation over the cross-section area

Along with stabilisation of thermal conditions at the inlet of the rollingline, there is homogenisation over the cross-sectional area of the material. As shown in the picture, the temperature profile during transport from the casting machine to the rollingline is cooler at the surface than in the middle. This is often called the natural temperature profile. Rapid heating in the induction heating machine alters the temperature profile, with the highest temperatures present at the surface. This is due to the typical power density distribution of induction heating. However, what is crucial is optimal temperature differences over the cross-section at the entry to the rollingline. This uniform temperature distribution within the billetis ensured by a mathematical model and optimal layout of the equalisation section. Billets with a uniform temperature distribution are easier to deform and thus ensure a stablerollingprocess. Deformation of billetsat a higher absolute or relative temperature requires lessrollingforce, so rollwear is reduced and roll life is extended.

Use in conventional rolling lines

With a conventional design, targeted reheating before rolling allows the furnace temperature to be lowered. This yields cost savings from the longer service life of the furnace and reduced scale formation. The induction machines from Elotherm for induction heating of long products consist of a barrier to protect the inductors, the induction heating section, and depending on the use case, a specifically matched insulated soaking section.