This specification covers steel cleanliness requirements for aircraft-quality ferromagnetic, hardenable corrosion-resistant steels by magnetic particle inspection methods to determine the presence of nonmetallic inclusions, measured in metric (SI) units. Applicable primarily to blooms, billets, tube rounds, stock for forging or flash welded rings, slabs, bars, tubing, and extrusions used in fabricating parts subject to magnetic particle inspection, but may be used for qualification of a heat, melt, or lot of steel.