a (b) (c) Fig 5 Type 430 stainless steel hot rolled to various percentages of reduction showing development of a banded structure consisting of alternate layers of ferrite (light) and martensite (dark) as the amount of hot work is increased. (a)63% reduction.(b)81%reduction.(c)94% reduction. 55 mL 35% HCl, 1 to 2 g potassium metabisulfite, 275 mL H2O (Beraha's tint reagent No. 2). 500x Depending on the kind and degree of segregation that develops during solidification, some degree of banding carries over to the wrought form. If banding is severe, it can lead to discontinuities that cause premature fail hg For example, Fig. 6 shows the fatigue fracture of a carburized and hardened steel roller. Banded alloy segregation in the metal used for the rollers resulted in heavy, banded retained austenite, particularly in the carburized case, after heat treatment When the roller was subjected to service loads, the delayed transformation of the retained austenite to martensite caused microcracks near the case -core interface. These internal microcracks nucleated a fatigue fracture that progressed around the circumference of the roller, following the interface between case and coreFig. 5 Type 430 stainless steel hot rolled to various percentages of reduction showing development of a banded structure consisting of alternate layers of ferrite (light) and martensite (dark) as the amount of hot work is increased. (a) 63% reduction. (b) 81% reduction. (c) 94% reduction. 55 mL 35% HCl, 1 to 2 g potassium metabisulfite, 275 mL H2O (Beraha's tint reagent No. 2). 500× Depending on the kind and degree of segregation that develops during solidification, some degree of banding carries over to the wrought form. If banding is severe, it can lead to discontinuities that cause premature failure. For example, Fig. 6 shows the fatigue fracture of a carburized and hardened steel roller. Banded alloy segregation in the metal used for the rollers resulted in heavy, banded retained austenite, particularly in the carburized case, after heat treatment. When the roller was subjected to service loads, the delayed transformation of the retained austenite to martensite caused microcracks near the case-core interface. These internal microcracks nucleated a fatigue fracture that progressed around the circumference of the roller, following the interface between case and core