The etching of a metal surface to accentuate gross structural details such as cracks, grinding cracks, hair carcks, etc. for observation at a magnification of ten diameters or less.

Macroetching is the selective attack of the surface with the object of revealing the features developed during processing of the rolls. In addition to the primary solidification pattern there may also be physical discontinuities which could be revealed by macroetching including voids, porosity, flakes, bursts, inclusions and cracks. Seams and laps, if rolled, may also be seen at the surface.

Deep chemical etching is used to characterize large-scale variations in material composition, structure, density, etc. This method is useful for evaluation of defects, and structure of rolls.

Macrostructure of roll cross section (Roll diameter: 250 mm).

Macrostructure of roll cross section (Roll diameter: 230 mm).