Straightening

Straightening is a necessary step in the heat treating process of many components.  Due to mechanical deformation and manifestation of stresses during heating and quenching, parts often warp to beyond acceptable tolerances with respect to straightness and flatness.  Therefore straightening operations become a necessity to bring the parts back within acceptable ranges.

Capability

ThermTech has straightening presses ranging up to 200 tons.  More importantly than equipment, ThermTech employs personnel with a great deal of knowledge and experience in all facets of straightening.

Process

Methods of straightening depend on material type, mechanical properties and geometry of the part being straightened.  Primarily straightening is done after heat treatment.  Parts in the annealed or normalized condition can be straightened easily.  Parts that are quench and tempered or carburized and hardened have many more considerations that determine when and how straightening can be accomplished.  

Not everything can be straightened after heat treatment.  Parts above 45 HRC can be extremely difficult to straighten and the risk of cracking during straightening is very high.  In this situation it becomes necessary to straighten the component at our near the tempering temperature or fixture during tempering.

Some tool steel components require torch straightening which is always a last resort because it involves heating areas of the part to above the austenite temperature therefore changing the hardness in localized areas.

Recommendations

When evaluating a component for heat treatment one should always consider distortion as a possibility in the final product.  This is especially true when heat treating shafts or plates.  Talk to the heat treater prior to sending the part in to determine risks and to discuss tolerances.  With respect to components that are sensitive to distortion heat treaters may be able to suggest processes or material changes that can lead to success in the final product.