PURPOSE: To recover the yield strength decreased by undermentioned plastic deformation without causing much decrease in bend precision and to prevent deterioration in the high specific strength characteristics of a Ti alloy by carrying out straightening by subjecting a Ti alloy coiled stock to a repetition of bending plastic deformations in forward and backward directions many times and then applying the prescribed heating treatment to the above.

CONSTITUTION: A Ti alloy coiled stock is subjected to a repetition of bending plastic deformations in forward and backward directions many times by using straightener rolls where the coiled stock is passed through a group of many staggeredly arranged rolls or by using a straight-line cutting machine by means of straightener barrel and bridge to undergo straightening and is then subjected to beating treatment at 250-650°C.