US 5,392,652 AGranted

Method and apparatus for inspection of metal objects utilizing variable angle ultrasonic transducer

AssigneeLambert, MacGill, Thomas, Inc.

InventorsKevin J. Levesque, David B. Richey

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Abstract

Presented is a method and apparatus for inspection through use of a variable angle ultrasonic transducer of metallic members such as pipes, conduits, plates and other formed metallic members normally having a surface regularity adhering to a predetermined standard of normalcy. Inspection proceeds in such a manner that irregularities in the surface of the member under test that lie outside the standard of normalcy are sensed, the degree of irregularity determined and converted into an electrical signal that is applied to continually variably control the angular relationship of the ultrasonic transducer with the surface of the metallic member being inspected whereby abnormalities within the metallic member may be reliably and accurately detected, displayed and recorded. In terms of apparatus, the ultrasonic transducer is provided with an arcuate sound transmitting surface, and the the transducer is mounted for pivotal rotation about an axis of rotation correlated to the radius of curvature of the arcuate sound transmitting surface. The transducer is also mounted for automatic axial and vertical displacement in relation to irregularities encountered during the test, with automatic pivotal rotation of the transducer being effected in correlation to the axial and vertical displacement.

Claims21

Dependent claims

The process of inspection of metallic objects normally having a surface regularity adhering to a predetermined standard of normalcy and including geometric and surface irregularities varying from said standard of normalcy to discover an abnormality therein and display and/or record the position and nature of the abnormality, comprising the steps of:

a) generating ultrasonic sound waves in a transducer adapted to impinge on a metallic object;
b) transmitting said ultrasonic sound waves into said metallic object under inspection at a predetermined angle correlated to a surface regularity adhering to said predetermined standard of normalcy;
c) receiving and displaying a reflection of said ultrasonic sound waves propagated within said metallic object to indicate the presence of an abnormality in said metallic object;
d) detecting in a continuous manner the surface irregularities on said metallic object under inspection;
e) measuring in units of length the extent of variation of said detected surface irregularities in relation to said surface regularity adhering to said predetermined standard of normalcy;
f) converting into electrical signals said measured variation of the surface irregularities from said predetermined standard of normalcy thereof;
g) applying said electrical signals to variably control the rotational repositioning of said transducer in relation to the surface of said metallic object being inspected whereby said predetermined angle of propagation of said ultrasonic sound waves within said metallic object are maintained constant despite said surface irregularities whereby abnormalities in said metallic body are reliably and accurately detected and displayed;
and
h) wherein said surface irregularities are detected by impingement of the transducer thereagainst and displacement of the transducer thereby.

6 more elements

An ultrasonic test probe for generating ultrasonic sound waves for transmission into metallic objects to inspect for abnormalities therein, comprising:

a) at least one transducer, wherein said at least one transducer comprises:
i) a piezo-electric member operable at a selected frequency in a range between 0.5 MHz and 25 MHz;
ii) a synthetic resinous delay line having first and second ends and operatively associated at said first end with said piezo-electric member and at said second end having an arcuate sound transmitting end surface adapted to transmit ultrasonic sound waves into a metallic object under inspection;
b) frame means encasing said at least one transducer and including oppositely extending bosses symmetrical about a rotative axis constituting the center of curvature of said arcuate sound transmitting end surface of the delay line;
and
c) means supporting said at least one transducer and said frame means for axial and vertical displacement in relation to said metallic object under inspection at a point of tangency of said metallic object with said arcuate sound transmitting end surface and rotational displacement of said arcuate sound transmitting end surface in correlation to said vertical displacement.

3 more elements

Dependencies are inferred from the claim text.