Page 105 - SSAB Welding Handbook Edition 2

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Welding handbook 18.0 Non destructive evaluations

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Fig. 18.2: Dye penetrant testing. Step 1) Appliance of penetrant. Step 2) Removal of excessive penetrant. Step 3) Appliance of developer.
Step 4) Detection of discontinuties. In this case cracks are revealed.

As a final measure, the chemicals from the penetrant fluorescent penetrant systems are used, the
testing should be removed in accordance with the evaluation of the joint must be done using UV
manufacturer. light to allow the discontinuity to fluoresce. In this
case, a colored background from the developer
The penetrant systems, including penetrants, is not required. This method can detect smaller
developers and solvents, can be divided into two discontinuities than dye penetrants since it achieves
groups: dye penetrant or fluorescent penetrant a higher contrast between the discontinuity and the
systems. These systems are developed to provide background.
a high contrast between the developer and the
marking from a discontinuity. If a discontinuity is The different steps of dye penetrant testing are
detected, the dye penetrant causes a mark that can illustrated in fig. 18.2.
be seen visually in a well lit surrounding. The
discontinuity indication color is typically red with
a white background from the developer. When

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all liability of any kind, including any damages, in connection with the use of the information and for their suitability for individual applications. 105
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.