1.1 These test methods cover a number of recognized procedures for determining the nonmetallic inclusion content of wrought steel. Macroscopic methods include macroetch,fracture, step-down, and magnetic particle tests. Microscopic methods include five generally accepted systems of examina-tion. In these microscopic methods, inclusions are assigned to a category based on similarities in morphology, and not necessarily on their chemical identity. Metallographic tech-niques that allow simple differentiation between morphologi-cally similar inclusions are briefly discussed. While the meth-ods are primarily intended for rating inclusions, constituents such as carbides, nitrides, carbonitrides, borides, and interme-tallic phases may be rated using some of the microscopic methods. In some cases, alloys other than steels may be rated using one or more of these methods; the methods will be described in terms of their use on steels.
