Achieving high flatness in metal strips is crucial for both finished products and efficient coil coating processes.
Tension leveling plays a key role in enhancing strip flatness and can be integrated into coating lines as a preparatory step or within specialized Tension Leveling Lines, ensuring optimal preparation and performance.
The tension leveling process entails submitting the strip to high tension (beyond the material’s yield point), thereby inducing a localized permanent elongation on the strip. This causes all the longitudinal fibers to have the same length and eliminates the edge waves and center buckles which are the typical flatness defects.
Besides the leveling equipment, which is the core of a Tension Leveling Line, other processes may be added as required by the type of material and the specific application.
Some of the processes that are typically added include:
- Side trimming
- Strip cleaning
- Surface oiling after leveling
Globus supplies complete Tension Levelling Lines as well as tension levelling units integrated into Coil Coating Lines. No matter what configuration is selected, Globus levelers provide a high degree of flatness enhancement down to a few I-units.
In the tension levelling process, the strip is leveled by locally bringing the material beyond the yield point using a combination of tension generated by bridle rolls and tension obtained by alternately bending the strip over small diameter rolls. This action causes permanent elongation of the longitudinal fibers, which makes their length evenly distributed across the width, eliminating internal stress and flatness defects, and delivering a high degree of flatness improvement.