AIRCRAFT STRINGER MATERIAL AND METHOD FOR PRODUCING THE SAME

摘要

An aircraft stringer material having high strength, small grain size, good resistance to stress corrosion cracking and very high degree of workability is produced from an aluminum base alloy consisting essentially of 5.1 to 8.1 wt.% Zn, 1.8 to 3.4 wt% Mg, 1.2 to 2.6 wt.% Cu, up to 0.20 wt.% Ti and at least one of 0.18 to 0.35 wt.% Cr and 0.05 to 0.25 wt.% Zr, the balance being aluminum and impurities by production method characterized by special annealing step including rapid heating to a temperature of 320 to 500.degree.C at a heating rate exceeding 11.degree.C/min. Further, a corrosion-resistant stringer material is also produced in a manner very similar to the above production method, using the above aluminum alloy as a core and AA7072 alloy as a cladding.