Patent ID: 8250923

Claim:
An ultrasonic inspection method comprising the steps of: placing an ultrasonic probe on a first surface of a first structure that is one of a tube and a vessel, which the first structure at least one of partially and entirely has a cylindrical shape, the first surface of the first structure being located on an opposite side to a second surface of the first structure on which the second surface of the first structure a welded part is present, the welded part joining the first structure and a second structure along at least one of a circumferential direction and an axial direction of the first structure having the cylindrical shape; transmitting an ultrasonic wave from the ultrasonic probe at an angle in an X′-Z plane defined by an X′ axis and a Z axis, when the direction of a line that is normal to the first surface of the first structure is defined as an X axis, a direction in which the welded part extends is defined as a Y axis, a direction perpendicular to the X axis and the Y axis is defined as a Z axis, and an axis obtained by rotating the X axis around the Z axis is defined as an X′ axis and wherein the X′ axis is a single axis; and receiving a signal which is reflected from a defect present in the welded part to detect the presence of the defect.