Flattening and Coating Line (FCL) for Silicon Steel Strip
For the final heat treatment process the transformer strip is coated with insulating varnish in an in-line process, dried and then straightened, using the integrated hot stretching equipment at controlled atmosphere, under controlled tension. In the adjacent soaking section the strip is sufficiently stress relieved and finally slow cooled through a multistage cooling section.
Key process are also connected to the removal of the residual MgO from the strip surface, light pickling/activation before insulation, possible laser scribing and side trimming.
Overview
LOI Thermprocess, with its over 40 years of experience, is the only company with the competence and knowledge, of the entire multi-stage thermal process chain, which is required for the production of grain-oriented electrical steel strip.
In the final stage of the heat treatment process, transformer strip is coated with insulating varnish in an in-line process and then dried in the first section of the furnace. The steel strip is heated further in a radiant tube furnace with a controlled atmosphere and then straightened using the integrated hot stretching equipment under controlled tension. This stage is followed by a soaking section to recover the material internal stresses and then by an accurate slow cooling process.
Key process and technologies are also connected to the removal of the residual MgO from the strip surface (suction of MgO powders in unwinding section, Dry and wet Brushing section), light pickling/activation of the strip surface before insulation, accurate coaters and varnish recirculating system at controlled temperature.
A particularly accurate strip tension control in the Furnace is also needed involving all the mechanical and electrical design.
Laser scribing unit for magnetic domain refining after the cooling section and Side trimming section in the exit section can be integrated in the line
Tenova Flattening and Coating Lines for Silicon Steel Strip are based on the following unique technologies:
- Special uncoiler with lateral coil containing plates, suction hoods, dry brushes, filtering unit to eliminate detached MgO during un-coiling
- MgO brushing-rinsing unit with special settling tanks to separate MgO liquid sludges
- Light pickling unit to eliminate residual MgO
- Special 4-roll coaters (double in standby) for insulation coating (Carlite or S3 tensioning coating)
- Accurate tension control through low inertia machines and double tension control loops on the bridles in process area;
- Special steering rolls at Furnace exit to improve camber
- Insulating varnish recirculation systems at controlled temperature
- Laser Scribing units (in-line or off-line)
- High precision side trimmers and scrap choppers or balers
Related Solutions
Europe
Wolfgang Eggert
General Manager Sales Heat Treatment of Steel Strip, Tenova LOI Thermprocess
China
Peizhong Wang
Director of Sales Tenova LOI Thermprocess, Tenova Technologies (Tianjin)
Modernization, Service & Spare Parts
Marc Reynaert
Head of Revamp & Modernization, Tenova LOI Thermprocess