Overbend Straightening

This technique is sometimes employed prior to, during, and/or after heat treat processing an item, to keep or make it straight enough to meet the customers’ requirements.  The principle of overbending is to apply a load to a piece that is supported on either side of an area that is causing it to have a T.I.R./F.I.M. beyond the customers’ specification.  T.I.R. being “total indicator reading” and F.I.M. being “full indicator movement ‘, as read on a digital or dial indicator, while measuring the total variation from highest to lowest gage reading taken at a given location. The applied load flexes the steel to a point of plastic deformation without cosmetic damage or reaching the point of exceeding its ultimate yield strength.

For steel products that have been hardened, or that are too large to bend with the available loading mechanism, an acetylene torch may be combined with the overbending process.  Flame Overbend Straightening allows these products to flex more readily than at room temperature.  The highest product temperature attained with localized flame heating should be kept below the point where it affects the hardness of the steel, but the higher the temperature used, the easier it is to cause the plastic deformation required.

A variety of straightening methods may be combined when necessary to bring about satisfactory results for the customer.