Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Areva Gmbh

Pipetronix Bmbh

Framatome Gmbh

Gerhard Hübschen

Frank Niese

Alexander Viskov

Herbert Willems

Gerd Dobmann

Jochen Kurz

Ralf Tschuncky

Otto-Alfred Barbian

Hans-Jurgen J Salzburger

Wilhelm Repplinger

Steffen Bergholz

Iris Altpeter

Hans-Georg Herrmann

Jürgen Rudolph

Ralf Tschunky

The present invention relates to a method for detecting temporally varying thermomechanical stresses and/or stress gradients over the wall thickness of metal bodies, in particular pipelines. In the method, the temperature on the outer surface of the body is measured in order to determine a temperature progression and stress progression therefrom. In addition, electromagnetic ultrasonic transducers are used at at least one measuring point on the outer surface in order to determine the progression of the stresses and/or stress gradients over time over the wall thickness of the body in conjunction with the result of the temperature measurement. The method allows the fatigue monitoring of pipelines even in the event of rapid stress changes.

Method for detecting temporally varying thermomechanical stresses and/or stress gradients over the wall thickness of metal bodies

An electromagnetic ultrasonic transducer for coupling-media-free generation and/or reception of ultrasonic waves in the form of linearly polarized transverse waves in and from a workpiece is disclosed, having at least one unit which converts the ultrasonic waves inside the workpiece and which is provided with a coil for generating, and/or detecting a high-frequency magnetic field and premagnetizing unit for generating a quasi-static magnetic field which superimposes the high-frequency magnetic field in the workpiece The coil is disposed in a torus-shape on at least one partially toroidal or U-shaped magnetic core, having two front ends which can be turned to face the workpiece. The front ends of the magnetic core, which can be turned to face the workpiece, are connected directly or indirectly to a magnetic flux piece which has a surface facing the workpiece and connecting the front ends with each other.

Electromagnetic ultrasound converter

Device for testing ferromagnetic materials

The invention relates to a method for non-contact, non-destructive testing of a test body of ferromagnetic and/or electrically-conductive material with ultrasound waves, comprising the steps of: producing in a near-surface region of the test body a low-frequency alternating magnetic bias field having flux lines generally parallel to a surface of the test body; producing high frequency alternating magnetic excitation fields in said near-surface region generally parallel to said surface during a time interval when the bias field is at a quasi-static maximum, adjacent excitation fields having opposing polarity and having flux lines lying in mutually parallel directions, whereby ultrasound waves are generated in the test body; and detecting high frequency alternating magnetic fields in said near-surface region during the same time interval when the bias field is at a quasi-static maximum and producing a signal therefrom representative of said ultrasound waves. In this method, the flux lines of said excitation fields lie generally parallel to the flux lines of said bias field, such that dynamic forces are electrodynamically generated in the test body in a direction normal to the surface of the test body, which launch longitudinal waves, Rayleigh waves and Lamb waves, and dynamic forces are magnetostrictively generated in the test body in a direction parallel to said surface, which launch transversal waves, Rayleigh waves and Lamb waves.

Non-destructive, non-contact ultrasonic material

Growing community of inventors

Saarlouis, Germany

Gerhard Hübschen