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Destructive testing, nick breaks.

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Olefazz

Mechanical
May 6, 2011
4
When examining nick breaks after the specimen is broken, I have encountered shiney spots in the weld metal. It isn't slag, non fusion, porosity, or fish eyes. I've been told by a welding engeneer that it was brittle fracture but would like other opinions. Several welding inspectors I have worked around will fail the weld test for these shiney spots. Someone please advise as to exactly what these shiney spots are, and should the weld test be disqualified? Olefazz
 
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These formations are sometimes known as 'ice' and are generally caused by large, unrefined brittle grains. They generally resuly from low interpass temperatures and/or fast travel speed. Simply put, a welding process parameter or technique needs to be changed.

This is not a desireable condition, but I would not reject a nick break for this alone, but insure that the welder is following the WPS for production welding.
 
The shiny areas are regions of brittle fracture caused by pockets of untempered martensite, if this is a carbon or low alloy steel.
 
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