T abstracts NDT Abstracts is a current awareness service compiled by the National NDT Centre, Harwell Laboratory, Didcot, Oxon, OXll 0RA, UK. The entries are drawn from over 500 British and International publications. Each issue concentrates on one or two subject areas.

The subjects covered in previous issues from February 1990 onwards are: Acoustic microscopy - February 1990; Concrete - April 1990; Eddy currents - December 1990; G a m m a tomography - June 1991; Image processing - June 1990; Magneto-acoustic emission and the Barkhamen effect - February 1991; Ultrasonic testing of composites - August 1990; Vibration testing - April 1991; X-ray tomography - October 1990

Radiographic inspection of welds 47440 Bjorkholm, P.J.; Parker, R.; Johnson, M. Design and nl~iication of a digital radiographic weld inspection system NDE: The Next Decade and Beyond. 1990 ASNT Spring Conference, San Antonio, Texas (United States), 19-23 Mar. 1990. pp. 187-189. ASNT (1990)

American Science and Engineering (AE&E) is now designing and building a digital weld inspection system under contract to Boeing Aerospace Corporation. The system will be used to inspect welds on the space station. The system is designed to image 1080" of continuous weld with a spatial resolution of 8 lp/mm and a sensitivity of 2-1t. The system consists of three basic components: the X-ray generation system, the X- ray detection system, and the data acquisition and display system.

46321 Mudge, P.J. Nondestructive testing of welds Metals and Materials Vol. 7, No. 5, pp. 286-289 (May 1991)

Nondestructive testing of welds is an important means of establishing whether sound joints have been produced. It is essential for high quality constructions that such tests are carried out owing to the large number of factors which can be detrimental to the production of flaw free welds. Crucial to the efficient application of nondestructive testing is an understanding of its capabilities and limitations. This article explains the characteristics of the principal methods.

45950 Bossi, R.H. Improved pipeline inspection using linescanning Sigma Research, Inc., Redmond, Washington (United States), PB90- 262221/GAR, 78 pp. (Nov. 1987)

Present inspection methodology is slow and imposes significant and costly time delays between welding and acceptance of the weld. An innovative approach to this inspection problem is to immediately follow the welding process with a linescan X-ray imaging system. Researchers have studied the potential of this technique. Calculations show that sufficient X-ray intensity combined with currently available detector sensitivity would allow weld scanning at a rate of 1 cm/s. The report contains the preliminary design of an on-line weld scanning system, including X-ray requirements, detection sensitivity, field ruggedness, and data analysis and archiving.

45738 Guu, A.C.; Rokhlin, S.I. Weld penetration control with radiographic feedback on weld pool depression Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Maine (United States), 23-28 Jul. 1989. Vol. 9B, pp. 1973- 1980. Edited by D.O. Thompson and D.E. Chimenti. Plenum Press (1990)

In this paper, control of weld penetration is accomplished by use of radiographic information on weld pool depression. During weld control based on comparison of the measured depressed pool depth and width with threshold levels, welding conditions are automatically adjusted to maintain required weld penetration.

45429 Shub, B.M.; Chibirova, L.G.; Kass, M.A. Electroradiographic inspection of the quality of welded joints in pipes V.E. Riecansky, Technical Translations, VR-4353 2 pp. (1990)

The authors describe the method of electroradiographic (ERG) inspection of the quality of welded joints in pipes of heating surfaces which does not require X-ray film and improves the productivity of inspection. Equipment developed by the Atomkotiomash Scientific and Production Organisation for mechanisa- tion of ERG inspection of the quality of welded joints in pipes of the heating surfaces directly in the welding line is described.

45428 Potapov, V.N.; Belyi, N.G.; Grom, V.S. Increasing the contrast of defect images in radiation inspection of welded joints V.E. Riecansky, Technical Translations, VR-4340 3 pp. (1990)

The method of consecutive application of the theory of small perturbations was used to obtain quantitative data on the effect of slit stopping down in radiation inspection of welded joints on the contrast of defect images. The experimental results which confirm the calculated data are presented.

45196 Anon. Summary report: X-ray real time (radioscopy) for weld inspection Welding in the World, Vol. 28, No. 5-6, pp. 74-83 (1990)

This report summarizes four published progress reports detailing the equipment, methods and application of real time radiography (radioscopy) for the inspection of welds. Radioscopy produces an image of the weld on a television display monitor screen and methods of image enhancement are detailed. This method of inspection has developed to be a competitor to radiography on film and has the possibility to develop further into an automated inspection method, using automatic image interpretation. Permanent records with no loss in image quality are available if required, using a laser and a rigid optical disc.

44784 Babcock & Wilcox Co.; (Vaughn, H.) Radiographic inspection of tube welds in panel walls U.S. Patent No. 4,924,481 (8 May 1990)

The radiographic technique allows tube welds in tubular membrane panel walls to be inspected for defects. A radiation source is installed between an adjacent pair of tube welds in a panel wall, and radiation receivers are closely secured around the perimeter of each tube weld so as to cover the critical areas of the tube welds which are to be inspected. The radiation receivers are exposed to radiation simultaneously and this creates an image so the perimeter surface of the tube welds so an assessment of their condition can be made.

44197 Potapov, V.N.; Belyi, N.G.; Groin, V.S. On increasing the contrast of flaw Images in the radiographic inspection of welds (In Russian) Tekhnicheskaya Diagnostika i Nerazrushayushchii Kontrol, No. 2, pp. 11- 14 (1989)

Using the method of a recent application of the theory of small perturbations, quantatitive data on the influence of slit diaphragming on the contrast of flaw images during the radiographic inspection of welds have been obtained. Experimental results supporting the theoretical data are presented.

44193 Shub, B.M.; Chibirova, L.G.; Kass, M.A. X-ray xeroradiographic quality control of welds in tubes (In Russian) Tekhnicheskaya Diagnostika i Nerazrushayushchii Kontrol, No. 2, pp. 75- 76 (1989)

The article describes the technology of an X-ray xeroradiographic method of quality control of welds in heating-surface tubes. This technology does not require the use of X-ray film and increases the productivity of testing. An installation developed by the Atomkotlomash undertaking for mechanising this method in-line with the welding operation is described.

44190 Bochenin, V.1. X-ray fluorescence method of surface flaw detection Industrial Laboratory, Vol. 55, No. 6, p. 694 (Dec. 1989)

Capillary flaw detection has been adapted here to industrial use. The use of the adsorbing surface is eliminated in the X-ray fluorescence method of surface flaw detection, which is faster than conventional capillary flaw detection. A penetrant liquid (which contains a chemical with high intensity X-ray fluorescence) is applied to the surface of the object to be inspected. The object surface is irradiated by a narrow X-ray beam, and cracks can be located from the radiation response of the chemical in the penetrant. This method is applied here to determining the size of cracks in welding seams of objects made from structural steels.

44186 Anon. Computed tomography of ancient Chinese urns Materials Evaluation, Vol. 48, No. 5, pp. 599,602 (May 1990)

214 NDT& E International August 1991