METHOD AND DEVICE FOR DIAGNOSING RESIDUAL STRESS OF TORSION BEAM, AND METHOD FOR MANUFACTURING TORSION BEAM

摘要

PROBLEM TO BE SOLVED: To provide a nondestructive inspection method which is suitable for managing a residual stress level of a product in a production line of torsion beams.SOLUTION: In the method for diagnosing a residual stress of a torsion beam, a torsion beam 20 which is a molding and a reference material formed by applying stress relieving annealing to the torsion beam are used as a measuring object, a temperature amplitude &Dgr;T caused by the thermoelastic effect at a lug part in a gradually changing part is measured by an infrared camera 9 while loading periodic external force on the measuring object within an elastic deformation area thereof, and residual stress of the torsion beam is evaluated from a temperature amplitude deviation &Dgr;&Dgr;T of the torsion beam against the reference material.