Outokumpu improves steel yield and reduces 3-4% of electric arc furnace energy consumption

New generation of electromagnetic stirrer enhances scrap and ferrochromium melting for a safer, more reliable and energy-efficient operation

Outokumpu Stainless AB (OSAB) in Avesta, Sweden specializes in the production of steel grades with a high chromium content. The addition of ferro-chromium in the arc furnace process, necessary to produce these particular steel grades does, however, have its disadvantages. With a higher melting point than the surrounding melt, the ferro-chromium can settle on the furnace bottom to form skulls.
Eliminating furnace bottom skulls with customized stirring solution - guaranteed performance and payback within a year


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90-ton electric arc furnace - EAF operation improvements


Total electrical energy consumption

- 8-10%

Electrode consumption

- 4-5%

Power-on time 


Tap temperature hit ratio 


Tap temperature reduction 


(reached 93%)
Tap weight hit ratio 


N2 consumption 
Average savings comparing results from three month before and three months after installation.
The challenge
  • How to eliminate furnace bottom skulls?
  • How to avoid variations in tapping weight?
  • How to reduce electrode and energy consumption?
  • How to make charging the scrap baskets more practical?
The solution
  • ArcSave®, new generation electromagnetic stirrer EMS
  • A specific stirring profile, controlling stirring intensity, duration and direction
  • A new lower furnace shell made from nonmagnetic stainless steel
  • A new temperature robot

The benefits
  • a more stabilized arc
  • more homogeneous steel bath
  • enhanced slag-metal reaction
  • more consistent EAF tapping conditions and AOD operation

How it works

ArcSave, ABB’s patented* electric arc furnace electromagnetic stirrer (EAF-EMS) mounted underneath the furnace bottom creates a whole bath mixing effect thus accelerates the homogenization of the temperature and chemical composition of the steel, increasing yield. It also contributes to safer operations. The complete ArcSave system comprises the electromagnetic stirrer, a frequency converter, a transformer and a water station. Wherever possible, equipment is pre-assembled and tested before delivery, and preparatory work including installation takes place during available down times.

The ArcSave’s powerful electromagnetic stirring enhances the melting of large scrap items and makes stratification less significant due to forced convection. The forced convection in the whole melt is instrumental in generating a homogenous temperature distribution and high scrap melting rate. The melt velocity achieved is roughly ten times faster, as compared to just having natural convection in the bath, and results in less power on time.

Increased steel yields, as well as savings in scrap cost and conversion are achieved, given that manufacturers can more readily attain a low carbon and oxygen mix, with a reduction in the slag’s iron oxide (FeO) content.
Damage at the slag-line level is reduced due the stirrer’s ability to lessen super heat during power on, lower tapping temperatures, the decreased FeO content in the slag and the diminished oxygen in the steel. As most critical damage tends to occur at the slag-line, by optimizing performance here, ArcSave helps producers enjoy refractory repair savings.
* ArcSave is a patented technology, ABB has several patents in this area including the ability to stir during tapping which breaks vortex formation in the melt
Pär Ljungqvist, EAF Process Developer, Outokumpu Stainless AB
“We managed to solve our furnace bottom skull problem using ArcSave®. The result is smoother, more predictable EAF operations at lower cost.’’

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