DEVELOPMENT OF FILMLESS TECHNIQUE FOR RECORDING DEFECTS IN SHIP WELDS

The U.S. Naval Ordnance Test Station investigated informally the feasibility of a direct-reading or filmless technique in radiography using a 300 mC Cobalt-60 source and a Geiger counter as a detector on a 1-in. thick steel welded test plate furnished by the Long Beach Naval Shipyard. A sketch and a radiograph of the welded test plate are shown. The tests were based on transmitted radiation, and the time required for a preset number of counts on a Potter chronograph was a function of the radiation intensity passing through a specific area of the weld. The larger the void, the shorter the time indicated on the counter. The memorandum also stated that preliminary tests indicated that it was feasible to place both the radiation source and the detector on the same side of the weld and to use a lead sheet radiation scatterer on the other side. All the following experiments were conducted with a steel plate as as a scatterer instead of the originally adopted lead sheet because the yield of the former was higher. Even though only radioisotopes are mentioned as radiation sources in the project assignment, the investigation was extended to include X-rays since a higher radiation intensity was expected from the 250 kvp X-ray equipment than from the available weak gamma source of 150 mC. The detectors used in these tests were as follows: a scintillator, an industrial Geiger counter (radiation monitor), and cadmium sulfide and cadmium selenide crystals.

  • Corporate Authors:

    Naval Ordnance Test Station

    China Lake, CA  USA 

    Ship Structure Committee

    National Academy of Science, 2101 Constitution Avenue, NW
    Washington, DC  USA  20418
  • Authors:
    • Bujes, J I
  • Publication Date: 1957-2-25

Media Info

  • Features: References;
  • Pagination: 35 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00327695
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: SSC-104 Prog Rpt.
  • Files: TRIS
  • Created Date: Feb 18 1981 12:00AM