NDTnet 1998 Aug, Vol.3 No.8

Abstract

The objective of the project was to develop an inspection method which could be applied during the weld process. In the production of large steel compoments thick welds are produced in several layers. It would be of great economic benefit to inspect the weld after completion of each layer and to repair detected defects immediately. For this purpose the components have to be inspected at elevated temperatures up to 250 centidegrees, depending on the welded steel alloy. The inspection methods involved here were ultrasonic testing, radiography, radioscopy and at the end destructing methods. It was SAUERWEIN's task to perform the radioscopic measurements.

In a first step the inspection methods have been evaluated and compared. For this purpose a set of TM and SAW welds with defined defects have been manufactured and investigated. Then SAUERWEIN has adapted his radioscopic system GAMMASCOPE to the environment of an industrial workshop for large steel components. The image detector has been protected against heat irradiation by means of a cooler with compressed air. To prevent a loss of image quality by magnetic fields, caused by the high electric current required for the weld process, a µ-metal shielding has been integrated into the cooler.

In a final test in the workshop of partner NORDON the inspection system has been tested during the weld process. Several welds with defects have been produced by TIG and SAW welding. The inspection has been performed after each layer. Even with some loss of image quality the results have been acceptable for weld inspection. A compilation of the results will be presented.The results have been directly transfered to the partner University of Surrey, which attended also the final tests with their evaluation system. They made immediately after welding an automated evaluation of the radioscopic images.

The inspection during the weld process is of great economic importance, since the radiographic examination after completion of the weld and a subsequent heating and repair wastes production time and energy. Filmless inspection saves also the chemical treatment of films and reduces the pollution of the environment caused by disposal of the photochemical liquids. Production plants with a high consume of films will save the cost of the investment by replacing the films by eletronic means.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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