Ultrasonic inspection method

Abstract

An ultrasonic inspection method that includes arranging an ultrasonic transmission element and an ultrasonic reception element symmetrically in relation to a straight line in a diameter direction orthogonal to the cylinder axis of a cylindrical inspection object, the inspection object being interposed between the ultrasonic transmission element and the ultrasonic reception element; transmitting ultrasonic waves from the ultrasonic transmission element at a plurality of positions in the diameter direction; receiving by the ultrasonic reception element the ultrasonic waves transmitted from the ultrasonic transmission element and transmitted through the inspection object by propagating through the inside of the inspection object; and inspecting the inspection object on the basis of a reception signal of the ultrasonic waves received by the ultrasonic reception element.

What is claimed is: 
     
         1 . An ultrasonic inspection method comprising:
 arranging an ultrasonic transmission element and an ultrasonic reception element symmetrically in relation to a straight line in a diameter direction orthogonal to the cylinder axis of a cylindrical inspection object, the inspection object being interposed between the ultrasonic transmission element and the ultrasonic reception element;   transmitting ultrasonic waves from the ultrasonic transmission element at a plurality of positions in the diameter direction;   receiving by the ultrasonic reception element the ultrasonic waves transmitted from the ultrasonic transmission element and transmitted through the inspection object by propagating through the inside of the inspection object; and   inspecting the inspection object on the basis of a reception signal of the ultrasonic waves received by the ultrasonic reception element.   
     
     
         2 . The ultrasonic inspection method according to  claim 1 , further comprising:
 moving the ultrasonic transmission element and the ultrasonic reception element parallel to the diameter direction in a state of the ultrasonic transmission element and the ultrasonic reception element being held symmetrically with respect to a straight line in the diameter direction; and   performing the step of transmitting ultrasonic waves while moving the ultrasonic transmission element and the ultrasonic reception element.   
     
     
         3 . The ultrasonic inspection method according to  claim 1 , further comprising:
 arranging a plurality of sets of the ultrasonic transmission element and the ultrasonic reception element parallel to the diameter direction; and   performing the step of transmitting ultrasonic waves by successively transmitting the ultrasonic waves from the plurality of ultrasonic transmission elements to the inspection object.   
     
     
         4 . The ultrasonic inspection method according to  claim 1 , further comprising:
 arranging a plurality of the ultrasonic reception elements side by side parallel to the diameter direction, and moving the ultrasonic transmission element along the diameter direction; and   performing the step of transmitting ultrasonic waves while moving the ultrasonic transmission element.   
     
     
         5 . The ultrasonic inspection method according to  claim 1 , further comprising:
 analyzing, as a first ultrasonic signal, a reception signal of ultrasonic waves that falls in the range of a time window provided before the arrival time of the ultrasonic waves to the ultrasonic reception element when there is no inspection object between the ultrasonic reception element and the ultrasonic transmission element, and   inspecting the inspection object on the basis of the analysis result of the first ultrasonic signal.   
     
     
         6 . The ultrasonic inspection method according to  claim 1 , further comprising:
 determining whether, prior to receiving by the ultrasonic reception element ultrasonic waves that propagated via the space outside the inspection object, a first ultrasonic signal that reached the ultrasonic reception element was detected, and   inspecting the inspection object on the basis of the detection result of the first ultrasonic signal.   
     
     
         7 . The ultrasonic inspection method according to  claim 1 , further comprising providing a shield between the ultrasonic transmission element and the ultrasonic reception element so as to block ultrasonic waves from reaching the ultrasonic reception element from the ultrasonic transmission element through the space outside the inspection object. 
     
     
         8 . The ultrasonic inspection method according to  claim 1 , further comprising:
 respectively arranging an additional ultrasonic transmission element and an additional ultrasonic reception element at positions at which the ultrasonic transmission element and the ultrasonic reception element are rotated by a predetermined angle in relation to the cylinder axis of the inspection object;   transmitting ultrasonic waves from the additional ultrasonic transmission element at a plurality of positions in the diameter direction of the inspection object;   receiving by the additional ultrasonic reception element the ultrasonic waves transmitted from the additional ultrasonic transmission element and transmitted through the inspection object by propagating through the inside of the inspection object; and   inspecting the inspection object on the basis of a reception signal of the ultrasonic waves received by the additional ultrasonic reception element.