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01-30-2020, 04:12 PM
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More than you probably want to know about Magnetic Particle Inspection (MPI)
 https://www.nde-ed.org/EducationReso...principles.htm VERY few testing labs have experience with pattern welded tubes, and interpretation of esp. Twist barrels can be difficult. A normal exam however would be reassuring   MPI is generally considered to be the best method for the detection of fine, shallow surface cracks in iron and steel, especially fatigue cracks. However, defects deeper in the material ie inclusions, may be missed. It of course tells you nothing about the bore, and for that reason direct observation with a bore scope, and wall thickness measurements of any vintage barrel are needed prior to use.
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http://sites.google.com/a/damascuskn...e.com/www/home |
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| The Following 2 Users Say Thank You to Drew Hause For Your Post: |
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03-10-2020, 08:34 AM
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Drew:
In the attached pictures - the top one: is the bright green line on the "top" barrel a crack ? Likewise, on the bottom picture, are the two bright green lines cracks (with the fine lines merely being normal features of twist barrels) ? |
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03-10-2020, 08:43 AM
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John: here is that barrel segment
 and radiography of the segment showed no evidence of cracks. The 2 markers are the ? indicators on MPI. The small lucent areas are felt to be bore pits 
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http://sites.google.com/a/damascuskn...e.com/www/home |
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