Evaluation of Strain Distribution of Sheet Formed Parts Using High-Frequency Ultrasonic Waves

Abstract

We studied a method of evaluating the strain distribution of a steel sheet after tensile forming using high-frequency ultrasonic wave. The longitudinal wave sound velocity after tensile forming, for eight different steel sheets with tensile strengths of 270 MPa to 980 MPa, increased in all samples. Furthermore it was also possible to evaluate strain distributions in press-molded parts formed by draw forming, one-step form forming, and two-step form forming. We found that the measurement results of ultrasonic waves correspond to the residual stress and FWHM in XRD measurements.