S-EMS in Roll
for slab caster strands
INTRODUCTION
S-EMS In Roll is Rotelec’s integrated strand electromagnetic stirring solution for slab casters. Unlike mold-flow-control systems such as MM-EMS, MM-EMB or MM-EMB+S, it works along the strand and is dedicated to internal solidification structure rather than mold meniscus behavior.
Integrated directly into slab-supporting roll segments, S-EMS In Roll is designed for applications where the steelmaker needs more equiaxed structure, better internal homogenization and lower sensitivity to ridging, roping or center defects. Today, this type of strand stirring is especially relevant for ferritic stainless steels and high-silicon steels, as well as for certain carbon steel grades.
HOW IT WORKS
The system is integrated inside slab-supporting rolls and can be arranged either side-by-side or face-to-face, depending on the segment design and the desired stirring pattern. In-Roll stirrers typically use roll diameters above 240 mm and are always used in pairs to maximize stirring forces. Like other slab strand stirrers, they generate a horizontal AC magnetic field using linear motor technology.
This electromagnetic action creates circulating loops in the liquid steel along the strand mixing the hotter upper liquid steel with the colder lower liquid steel. In single-stage configuration, the induced flow is a butterfly pattern. In double-stage configuration, it becomes a triple-zero stirring pattern, providing stronger thermal homogenization and more consistent enlargement of the equiaxed zone. The compact footprint and optimized power demand of about 120 kVA per pair also make the concept attractive where space,integration and power consumption matter.
ROLE IN THE PROCESS AND PLANT INTEGRATION
S-EMS In Roll is particularly strategic where the caster has to improve internal solidification structure without major mechanical intrusion into the upper strand and where double-stage stirring may be required. Compared with Box Type strand stirrers, the In-Roll concept offers easier positioning at different strand locations and can be used lower in the caster where roll diameter is larger.
From a plant perspective, the product has to be engineered together with the segment design, roll arrangement, cooling concept, available installation diameter and the targeted single-stage or double-stage stirring strategy. Its value lies not only in compact hardware, but in the ability to configure the stirring pattern around the real process target.
For slab casters producing ferritic stainless, high-silicon or other grades sensitive to internal structure and ridging or roping, S-EMS In Roll is a highly effective integrated stirring solution. Contact Rotelec to define the most suitable In-Roll configuration for your slab size, superheat range and product mix.
KEY BENEFITS
- Single-stage stirring for low-superheat casting and double-stage stirring for higher superheat and stronger thermal homogenization.
- Tailored flow control through butterfly or triple-zero stirring patterns that actively mix hotter liquid steel with colder liquid steel.
- Enhanced internal structure through equiaxed grain formation, with significant reduction of center porosity and segregation.
- Reduction of ridging and roping in ferritic stainless and silicon steels, plus lower crack susceptibility in carbon grades.
- Easy integration into roll segments with limited impact on caster mechanics and lower maintenance than bulkier external systems.
- Rapid payback through quality improvement, lower downgrade and better suitability for demanding slab grades.
