WELDED PART MEASURING METHOD AND WELDED PART MEASURING INSTRUMENT

PROBLEM TO BE SOLVED: To provide a penetration depth measuring method and a penetration depth measuring instrument for a welded part, allowing nondestructive and noncontact measurement, with high applicability. SOLUTION: A transmitting laser beam is emitted to excite an ultrasonic wave in a welded part 6, a reflected wave reflected on a bottom face 6a of the welded part 6 is received by a receiving laser beam emitted toward the welded part 6, a penetration depth of the welded part 6 is measured based on a pulse width H of the received reflected wave, and the penetration depth of the welded part 6 is thereby measured nondestructively and noncontactly. The penetration depth measuring method and the penetration depth measuring instrument are applicable even when the welded part 6 is narrow or complicated in its shape, since an ultrasonic sensor does not contact with the welded part via a liquid medium, although required in measurement using an ultrasonic wave in the prior art. COPYRIGHT: (C)2008,JPO&INPIT