M-EMS
Mold electromagnetic stirring for billet and bloom casting
INTRODUCTION
M-EMS is Rotelec’s mold electromagnetic stirring solution for billet and bloom casters. Derived from the Magnetogyr© Process commercialized since 1977, it acts at the most sensitive point of initial solidification: the mold. This is where meniscus behavior, first-shell formation and the conditions that govern surface quality, internal structure and casting regularity are established.
Positioned in the mold, M-EMS creates controlled liquid steel movement, accelerates superheat removal and improves solidification uniformity. The result is a more stable casting process and a cast product that starts forming under better thermal and metallurgical conditions from the very beginning.
HOW IT WORKS
In billet and bloom casters, electromagnetic stirring is rotative. The stirrer surrounds the casting section and acts like the stator of an AC motor fed by 3-phase electrical current. The liquid steel behaves like the rotor and is put in rotation around its axis in a plane perpendicular to the casting direction. The movement propagates above the stirrer by viscosity and below the stirrer by inertia.
Positioned in the mold, M-EMS combines active cleaning of the meniscus and washing of the solidification front with earlier and more uniform superheat removal. This combination promotes more regular initial solidification, increases the formation of equiaxed crystals and creates better conditions for internal quality. The technical value of M-EMS lies in this combination of thermal and flow effects, not in steel movement alone.
ROLE IN THE PROCESS AND PLANT INTEGRATION
M-EMS is especially relevant in plants that want to reduce defects linked to the initial solidification phase and improve the balance between quality and operational yield. The best configuration depends on section size, steel grade, casting speed and metallurgical targets. There is no universal setup: the selected solution has to match the real casting conditions.
From a plant perspective, M-EMS is developed as an integrated system that combines stirrer, dedicated power supply, cooling, automation and process control. Rotelec’s approach is to keep each strand independent, with its own transformer and PLC, using low-frequency 3-phase VVVF transistor inverters for current and frequency control. Water quality, protection logic and full workshop testing are integral parts of the overall solution and are a prerequisite for successful commissioning and increased equipment lifetime.
For billet and bloom producers looking to improve product quality and casting stability from the very first point of the process, M-EMS is a high-value process lever. Contact Rotelec to define the most suitable configuration for your caster conditions and metallurgical targets.
KEY BENEFITS
- Improved surface and subsurface quality through active cleaning of the meniscus and washing of the solidification front.
- Earlier and more uniform superheat removal in the mold, promoting equiaxed grain formation and better internal quality.
- More uniform shell thickness, with direct benefits for casting speed, breakout prevention.
- Strong reduction of centerline porosity and centerline segregation, with better results than strand stirring in many billet and bloom applications.
- Higher caster productivity, wider access to higher-quality grades and a higher share of billets and blooms qualified for premium applications.
- A proven solution for quality-oriented billet and bloom casters where surface, subsurface and center soundness all matter at the same time.
