Observations on Corrosion Resistance Of High Strength Stainless Steels for Aircraft

Stainless steels of the precipitation hardening type are used extensively in airframe components. In this paper, compositions and properties of several of these alloys are described. The corrosion performances of the Armco 17-4 PH and 17-7 PH precipitation hardening alloys are compared with those of other hardenable stainless steels. The results of accelerated corrosion tests with these materials in both bar and sheet form are reported for a number of acids of varying concentrations and temperatures. Data also are presented for the new precipitation hardening stainless alloy PH 15-7 Mo. Properties needed in materials used for aircraft structures are itemized. Variables affecting corrosion resistance of precipitation hardening stainless steels are discussed briefly. Other topics covered include resistance to high temperature-high purity water, effects of nitriding, atmospheric corrosion resistance, resistance to sea water, galvanic corrosion, stress cracking, and brazing and welding. 6.2.5