Metallographic Examination of Tensile Bar 47 Milwaukee Forge & Machine Co., Milwaukee, Wisconsin

摘要

This investigation was undertaken so that the above company could determine whether their procedure was satisfactory. No acceptability opinions of this Arsenal were asked for. The fracture of the test bar should be described as: cupped, pitted with small nonmetallic streaks. The steel was dirty but of commercial grade. The nonmetallics were small, but fairly uniformly distributed. Etching with 'Oberhoffer's Reagent' showed that the steel was decidely dendritic in both planes 90 degrees to each other. High temperature normalizing prior to heat treatment, and preferably before forging, would reduce the dendritic condition and improve the physical properties.