A wire with fluctuating initial parameters, e.g. fluctuating material parameters, initial curvature and alternating internal stresses, will be left with varying final curvatures after straightening. The wire is therefore "killed" by severe bending with straightening rolls in at least one plane in order to produce a final curvature in a single plane.
This "killing" is performed by special straighteners of type TR and TRV. Through the application of severe alternating bends with small bending radii the curvature fluctuations are reduced and the wire's internal stresses changed.
If a TR or TRV straightener is used in combination with a conventional straightening system, a semi-automatic straightening system, or a straightening system with an automatic roll positioner, then the straightening result will be affected by the resulting reverse tension.
See Also
Adapted from “"We do it straight" — Wire Straightening”, p. 103 (ISBN 3-00-005897-4).