This paper reviews the properties of aluminum alloys that are especially desirable for pressure vessels and certain chemical and processing equipment.Fourteen of the alloys covered by ASTM Specification B 209-60 T, having specified tensile strengths in the annealed condition ranging from 9500 to 42,000 psi, are approved by the ASME Code for pressure vessel applications.Some particular advantages of aluminum are resistance to a wide range of corrosive media, a colorless corrosion product and ease of fabrication.New developments in welding and alloys have made welding of aluminum exceedingly rapid and inexpensive. While the strengths of aluminum at elevated temperatures restrict its general application to temperatures below about 400 F, its low temperature properties make it outstanding for use at sub-zero temperatures.There is little change in ductility as temperature decreases and the brittle transition associated with carbon steel is absent.