Several defective shape of steel strips controlled
Steel production, the thickness of the strip (thickness ≥1.5mm) will appear L Alice, thin strip (thickness ≤0.7mm) will appear edge wave and the wave problem.
1, L Alice
Roll diameter is too small, or the strength properties of steel is not high, these problems occur when coiling. The common roller leveler, is up and down two rows of mutually staggered correction roller on the strip were several positive and negative bending the strip repeatedly produce plastic deformation, changing the stress state of the strip surface, to produce Alice Qu strip straightening is more feasible. Therefore
1) Prevention: appropriate to increase the winder drum diameter, will help reduce the severity of Alice L.
2) Countermeasures: increasing annealing temperature, lower annealing rate, thereby reducing the yield strength of the strip, is more conducive to the next unit uses the roller leveler eliminated.
2, edge waves
Cold-rolled steel strip width direction thickness distribution as "the male", when the winding tension is mainly concentrated in the central strip, so that the width of the center longitudinal compressive strain plastically, resulting in side waves.
Edge wave preferably stretch straightening or tension leveling, the strip along the length of the strip of plastic deformation to change the internal stress. Is applied along a longitudinal direction of the strip tensile stress, this stress greater the deeper the plastic deformation zone, when the pull of gravity to a certain value, the depth of plastic deformation exceeds the centerline, the strip extending along the length, to achieve a tensile straightening straight. Therefore
1) Prevention: to reduce the strip crown, can effectively reduce the take-up of stress concentration; appropriately reduced winding tension, so that the innermost coil maximum compressive stress is small enough.
2) Countermeasures: the next unit uses tension leveler is easy to eliminate.
3, the wave
Mainly due to the take-up stress concentrated at the center of the strip width caused. Should:
1) Prevention: to reduce the strip crown, can effectively reduce the take-up of stress concentration; appropriate to reduce the winding tension.
2) Countermeasures: the next unit uses tension leveler is easy to eliminate.
