TABLE OF CONTENTS Wrought compositions that do not respond to strengthening by heat treatment mainly comprise the various grades of aluminium as well as alloys with manganese or magnesium as the major additions, either singly or in combination (Table 3.2). Approximately 95% of all aluminium flat rolled products (sheet, plate and foil) are made from these three alloy groups. Packaging, transportation and building and construction represent the largest usage of non-heat treatable (NHT) sheet and the three major criteria for selecting and developing these products are:
structural based on strength and durability
formability based on complexity and productivity in making the final part
surface quality based on finishing characteristics, reflectivity or general appearance.
Each product has a particular balance of requirements.
NHT alloys can provide a very wide range of tensile properties and Fig. 3.17 shows that yield strengths between 20 and 500 MPa are possible from the 1xxx, 3xxx and 5xxx classes of alloys fabricated in tempers ranging from the annealed O to the severely cold worked H19 conditions. Strength is developed by stain-hardening, usually by cold-working during fabrication, in association with dispersion-hardening (Al Mn) and/or solid solution hardening (Al Mg) or both (Al Mn Mg). The miscellaneous alloys in the 8xxx series mostly do not respond to heat treatment and are used for specific applications such as bearings and bottle caps. An Al 1Zn alloy designated 7072 serves as cladding to protect a number of other alloys, e.g. 2219, 7075, from corrosion (Section 3.1.5) and...
