Luders LinesBack to Top
Elongated surface markings or depressions, often visible with the unaided eye, that form along the length of a round or sheet metal tension specimen at an angle of approximately 55' to the loading axis. Caused by localized plastic deformation, they result from discontinuous (inhomogeneous) yielding. Also known as Luders bands, Hartmann lines, Piobert lines, or stretcher strains.
Source: The OHIO State University