Patent ID: 6920792

Claim:
A guided wave electromagnetic acoustic transducer for detection of defects and/or or variances in the physical properties of metallic products including rods, wires, bars and tubes, all having a central axis, transmitting and detecting acoustic waves in these products, said transducer comprising a housing means, electromagnetic means within said housing for establishing a static magnetic field in said metallic products being inspected, electrical conductors for wrapping around said metallic products to encircle the same for producing eddy currents in said products, said conductors being energized by a pulse of a few cycles of high frequency alternating voltage which produces an alternating field in said metallic products, which, in turn, produces eddy currents which flow around the circumference of the section of the metallic product being tested, and means for inducing said eddy currents in said electrical conductor to produce, by the interaction of said eddy currents and said static magnetic field, Lamb waves which propagate along said metallic products in two directions, and means for detection of said Lamb waves to allow said transducer to detect any defects or variances.