Salzgitter Mannesmann Forschung GmbH (Salzgitter, Germany):

Stolzenberg M., Dr. Nat., Expert in Non-Destructive Testing

Tata Steel Research Development and Technolohy (Ijmuiden, Netherlands):

van den Berg F., Dr., Principal Scientist

Thyssen Krupp Steel Europe AG (Duisburg, Germany):

Dürr W., Dr. Nat., Team coordinator, Testing Equipment, Research and Development

AG der Dillinger Hüttenwerke (Dillingen, Germany):

Hoffmann U., Mag. Eng., Head of Sales Dept. and Non-Destructive Testing

Steel Institute VDEh (Düsseldorf, Germany):

Moninger G., Mag. Eng., Head of Specialized Committee of Non-Destructive Testing and Measuring Devices, günther.moninger@vdeh.de

Exact holding of the technological process in production of steel strip and sheets is considered as decisive factor for manufacturing high-quality products with the same properties along the length. To confirm it, it is necessary to determine different material parameters along its length, not only points in the end parts of a strip. Therefore, contact-free methods of non-destructive testing that can be incorporated in production lines should be applied. For this purpose, the work group of the Specialized Committee for Non-Destructive Testing and Measuring Devices of the Steel Institute of the German Union of Metallurgists (VDEh) has conducted investigations of the most important methods described in this paper. Used methods of non-destructive control are examined, among them ultrasonic control and electromagnetic processes. Different systems for estimation of material properties, such as Impoc process, Hacom measuring system, MFIA system and 3MA system, are analyzed. For each of them measuring and operating principles, data evaluation, state and task of equipment, improvement potential as well as area of usage of the results are presented in details. It is shown that laser and ultrasonic methods make it possible and acceptable to conduct measurements in high-temperature area above Curie point. It is connected with definite advantages in the cases when structural properties should be determined as soon as possible during technological process. Therefore, consequent improvement of ultrasonic devices can be an essential step in the direction of further development of the methods for on-line estimation of material properties and improvement of product quality.

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