This specification covers steel cleanliness requirements for aircraft-quality ferro-magnetic, hardenable, corrosion-resistant steels by magnetic particle inspection methods. Applicable primarily to blooms, billets, tube rounds, stock for forging or flash welded rings, slabs, bars, sheet, strip, plate, 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.