Flake

 A short, discontinuous internal crack in ferrous metals attributed to stresses produced by localized transformation and hydrogen solubility effects during cooling after hot working. In fracture surfaces, flakes appear as bright, silvery areas with a coarse texture. In deep acid-etched transverse sections, they appear as discontinuities that are usually in the midway to center location of the section. Also termed hairline cracks and shatter cracks.
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