This document specifies a metallographic test method for determining the non-metallic inclusion level in metal powders using a powder-forged specimen. This test method is applicable to repress powder-forged test specimens in which there has been minimal lateral flow (<1 %). The core region of the powder-forged test specimen must not contain porosity detectable at 100x magnification.
This test method can also be applied to determine the non-metallic inclusion content of powder-forged steel parts. However, in parts where there has been a significant amount of material flow, the near-neighbour separation distance needs to be changed, or the inclusion sizes agreed between the parties need to be adjusted.
This test method is not applicable for determining the non-metallic inclusion level of parts that have been forged such that the core region contains porosity. At the magnification used for this test method, residual porosity is hard to distinguish from inclusions. Too much residual porosity makes a meaningful assessment of the inclusion population impossible.
This test method can also be applied to materials that contain manganese sulphide (admixed or prealloyed), provided the near-neighbour separation distance is changed from 30 µm to 15 µm.
