Method and apparatus for ultrasonic inspection of weldments

Claim 3

The method of claim 1 wherein the ultrasonic energy of said transmitted beam is pulsed.

Claim 4

The method of claim 2 wherein said zone of interest is a weldment in said material.

Claim 5

The method of claim 3 wherein the steps of detecting said redirected ultrasonic energy comprise: a. sensing said redirected ultrasonic energy which exits from said material at said surface and subStantially normal thereto within an area overlying that portion of the weldment intersected by said refracted beam; b. converting said sensed ultrasonic energy to electrical signals representative of said sensed ultrasonic energy; and c. providing an output indication responsive to said electrical signals representative of said sensed ultrasonic energy.

Claim 6

The method of claim 3 wherein said oblique angle at which said refracted beam intersects said weldment is between 40* and 50*.

Claim 7

The method of claim 3 wherein said portion of the weldment intersected by said refracted beam at any instant is less than the entire depth of said weldment in said material and said refracted beam is scanned across the entire depth of said weldment.

Claim 8

The method of claim 6 wherein said scanning of the weldment depth with said refracted beam comprises sequentially generating a plurality of beams of pulsed ultrasonic energy, each said beam being parallel the other and each said beam of said plurality being incident with said surface at a different location along a line extending from said weldment to an outer limit.

Claim 9

The method of claim 6 wherein said scanning of the weldment depth with said refracted beam comprises: moving said beam which is incident on said surface relative to said weldment such that the location of beam incidence with said surface moves along a line extending between said weldment and an outer limit and the direction and angle of incidence of said beam with said surface are maintained constant.

Claim 10

The method of claim 8 wherein said weldment is an elongated seam and said generated ultrasonic beam moves relative to said material is a direction parallel said elongated weld seam to scan the entirety of said weld seam.

Claim 11

The method of claim 8 wherein the step of detecting said redirected ultrasonic energy comprises: a. sensing said redirected ultrasonic energy which exits from said material at said surface and substantially normal thereto within an area overlying that portion of the weldment intersected by said refracted beam; b. converting said sensed ultrasonic energy to electrical signals representative of said sensed ultrasonic energy; and c. providing an output indication responsive to said electrical signals representative of said sensed ultrasonic energy.

Claim 12

The method of claim 10 including the steps of: a. providing an electrical position reference signal for each ultrasonic pulse generated, said reference signal indicating the presence of said pulse at a predetermined location; and b. comparing said electrical signals representative of said sensed ultrasonic energy with said position reference signal whereby the time lapse therebetween is indicative of the location of a discontinuity in said weldment.

Claim 13

The method of claim 11 further including the step of electrically gating said electrical signal representative of sensed ultrasonic energy to pass only signals occurring within a predetermined time span following the generation of each ultrasonic pulse.

Claim 14

In ultrasonic inspection apparatus for examining a zone of interest extending a depth of at least about 4 inches into a material from a surface thereof, the combination comprising: a. transducer means for transmitting a beam of ultrasonic energy, said transducer means positioned and oriented to direct said beam at said surface of said material in a direction and at an oblique incident angle thereto which result in the propagation in said material of a refracted beam of ultrasonic energy in the longitudinal wave mode which is incident with and intersects said zone of interest at an oblique angle to a line normal to said surface and passing through said zone of interest, said incident ultrasonic energy being redirected upon contacting a discontinuity in said zone of interest; b. means coupled to said transmitting transducer means for electrically stimulating said transmitting transducer means to provide said beam of ultrasonic enErgy; c. ultrasonic transducer means positioned over said zone of interest intersected by said incident refracted beam for receiving any said redirected ultrasonic energy exiting therefrom substantially normal to said surface of the material thereat, said receiving transducer means providing an output signal responsive to said sensed ultrasonic energy; and d. read-out means coupled to said sensing transducer and responsive to said output signal corresponding with said received redirected energy for providing as indication of the presence of a discontinuity in said zone of interest.

Claim 15

In ultrasonic inspection apparatus for examining a zone of interest extending a depth of at least about 4 inches into a material from a surface thereof, the combination comprising: a. transducer means for transmitting a beam of ultrasonic energy, said transducer means positioned and oriented to direct said beam at said surface of said material in a direction and at an oblique incident angle thereto which result in the propagation in said material of a refracted beam of ultrasonic energy in the longitudinal wave mode which is incident with and intersects said zone of interest at an oblique angle to a line normal to said surface and passing through said zone of interest, said incident ultrasonic energy being redirected upon contacting a discontinuity in said zone of interest; b. means coupled to said transmitting transducer means for electrically stimulating said transmitting transducer means to provide said beam of ultrasonic enErgy; c. ultrasonic transducer means positioned over said zone of interest intersected by said incident refracted beam for receiving any said redirected ultrasonic energy exiting therefrom substantially normal to said surface of the material thereat, said receiving transducer means providing an output signal responsive to said sensed ultrasonic energy; and d. read-out means coupled to said sensing transducer and responsive to said output signal corresponding with said received redirected energy for providing as indication of the presence of a discontinuity in said zone of interest.

Claim 16

The apparatus of claim 13 wherein said zone of interest is a weldment and said means for electrically stimulating said transmitting transducer means comprise a source of pulsed electrical energy and said transmitted beam is pulsed ultrasonic energy.

Claim 17

The apparatus of claim 14 wherein said transducer means for transmitting said ultrasonic beam comprise: a. a plurality of closely spaced parallelly oriented ultrasonic transducers extending in alignment from said receiving transducer to an outer limit and being equidistant from said surface; and b. said means for electrically pulsing said transmitting transducer means is operative to pulse each said transducer of said plurality in sequence.

Claim 18

The apparatus of claim 14 wherein said transmitting and said receiving transducer means are spaced from said surface of said material, a liquid acoustical coupling medium extends between said transducers and said surface, and collimating means extend from said receiving transducer substantially to said surface for restricting the ultrasonic energy admitted to said receiving transducer to that which exits from said surface substantially normal thereto within the cross sectional area of said collimating means.

Claim 19

The apparatus of claim 16 wherein said acoustical coupling medium is water, said material is steel and said transmitting transducer means are oriented at an angle of less that 14* from the normal to said surface of said material.

Claim 20

The apparatus of claim 14 wherein said transmitting transducer means are plural and even in number, one-half of said number positioned to one side of said receiving transducer means and the other half of said number positioned to the other side of said receiving transducer means and said transmitting and receiving transducer means all being in a common plane.

Claim 21

The apparatus of claim 14 including means for moving said transmitting transducer means relative to said receiving transducer means in a path parallel said surface and extending from adjacent said receiving transducer to an outer limit whereby said refracted beam of longitudinal waves is scanned across said weldment in a direction normal to said surface.

Claim 22

The apparatus of claim 19 wherein said transmitting transducer means are plural and even in number, oone-half of said number positioned to one side of said receiving transducer means and the other half of said number positioned to the other side of said receiving transducer means and said transmitting and receiving transducer means all being in a common plane.

Claim 23

The apparatus of claim 20 wherein said weldment is an elongated seam and said transmitting transducer means are movable relative to said receiving transducer means in a direction perpendicular to said elongated weld seam.

Claim 24

The apparatus of claim 21 including means for providing relative motion between said material and said transmitting and receiving transducer means in a direction parallel the elongated extend of said weld seam to scan the entirety of said weld seam.

Claim 25

The apparatus of claim 22 including normal beam, ultrasonic pulse echo inspection means, positioned ahead of said transmitting transducer means in said direction of motion parallel said weld seam and movable therewith for preliminarily inspecting that portion of said material adjacent said weldment prior to propagation therethrough of said refracted longitudinal wAve beam.

Claim 26

The method of claim 1 wherein said beam of pulsed energy is directed at said surface in an incident direction and oblique angle thereto resulting in said refracted beam in said longitudinal wave mode intersecting said zone of interest before contacting the back surface of said material.

Claim 27

The method of claim 24 wherein the depth of said zone of interest in said material exceeds 6 inches.