This British Standard is the second revision in metric terms of one of a series for aluminium and aluminium alloys in various wrought forms for general engineering purposes, the preparation of which was authorized by the Non-ferrous Metals Industry Standards Committee. In accordance with International agreement this introduces N/mm2 as the unit for expressing stress values but otherwise the standard reflects only minor cbanges since the 1969 edition.
Others in the series are:
BS 1470. Wrought aluminium and aluminium alloys for general engineering purposes, Plate, sheet and strip.
BS 1471. Wrought aluminium and aluminium alloys for general engineering purposes. Drawn tube.
BS 1472. Wrought aluminium and aluminium alloys for general engineering purposes. Forging stock and forgings.
BS 1474. Wrought aluminium and aluminium alloys for general engineering purposes. Bars, extruded round tube and sections.
BS 1475. Wrought aluminium and aluminium 'alloys for general engineering purposes. Wire.
In preparing the previous revision of this metric specification cognizance was taken of the recommendations of the International Organization for Standardization (ISO): Alloy compositions and properties were brought in line with ISO recommendations where this was practicable and the temper designations quoted are those proposed by ISO. Thus work-hardened tempers of the strain-hardened materials, formerly show as 1/4H, 1/2H, 3/4H and H, are designated with the appropriate symbol selected from the range HI to H8, which represents a scale of increasing strength. The condition of heat-treated alloys is also indicated by the letter T followed by a B, D, E, F or H indicating the precise condition following the heat treatment.
Advantage was also taken of the opportunity to rationalize the number of materials offered and certain alloys and purities whose usage did not justify retention, were deleted. This applied to aluminium 1 C.
All tables of tolerances were reviewed and metric values in accordance with latest production practices are quoted.
In this edition the stress values have been converted into SI units (N/mm2) from the original hbar values.
Appendix A gives information relating to forms of material available, and in
Appendix B information is given on annealing and heat. treatment.
As a major step towards alignment of aluminium and aluminium alloy compositions on an international basis, a substantial number of countries have agreed to adopt a 4-digit classification for alloy composition designation. This system is administered by the Aluminum Association Inc., who issue the 'Registration Record of International Alloy Designations and Chemical Composition Limits for Wrought Aluminum Alloys', By amendment, it has been decided to introduce this system into the British Standards concerned with these types of material in place of the material designations formerly used. In some cases, minor compositional changes are also involved. The details of the system are given in appendix C and a cross-reference table between the new, the old and the nearest equivalent ISO designations is included as appendix D.
The temper designations and associated mechanical property requirements remain unaltered for the present and therefore may not necessarily align precisely with those in the standards of other countries.
