Instrument for testing materials

US4578999A · kind A · utility

Assignees

• Mannesmann AG · DE
• Nukem, LLC · DE

Inventors

• Klaus Abend · Büdingen, DE
• Gerhard Huschelrath · Laufach, DE
• Wolfgang Bottger · Ködnitz, DE
• Heinz Schneider · Düren, DE
• Karl Laudenbach · Gießen, DE

Key dates

• Filing date: Feb 10, 1982
• Grant date: Apr 1, 1986
• Expiry date: Feb 10, 2002

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2291/0422
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An instrument for testing of test pieces made of paramagnetic or diamagnetic material as well as of ferromagnetic materials above their Curie point for material defects and/or dimensional accuracy, especially for testing of tubes and slabs above 1000.degree. C. The instrument comprises an electromagnetic transducer (EMT) having magnetic pole shoes and eddy current exciting and receiving windings; and an electronic signal processing unit. The inner pole shoe is conically tapered and fabricated from individual sheets parallel to one another and insulated from each other to prevent the formation of eddy currents that would give rise to undesirable ultrasonic waves that might interfere with the testing process. The pole shoes are positioned so as to develop a magnetic field parallel to the test piece, and the eddy current exciting and receiving windings are heat-insulated with respect to the test piece.