BS EN 1706:2020 covers the chemical composition of aluminium casting alloys. Last published in 2010, the new standard has been extensively revised. This blog post details the changes.
BS EN 1706:2020 Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties specifies the chemical composition limits for aluminium casting alloys and the mechanical properties of separately cast test pieces for these alloys. It includes an annex on the selection of alloys for a specific use or process. This standard was first published in 1998 and then revised in 2010. The 2020 standard is its second revision.
This standard is an important specification in the UK because most aluminium is recycled here. For use by castors in engineering, automotive, aerospace gearing and investment casting, its use can give end users confidence. It’s also a valuable standard for designers and architects, and when castors, producers and designers are using the same standard it creates a level playing field. Ultimately, this standard helps create better products.
However, it was felt on review that the standard had not kept up with current methodologies and so an extensive rewrite was undertaken. The following outlines what’s new in the 2020 standard.
A thorough revision
To begin with, normative reference BS EN 10002-1 was replaced by BS EN ISO 6892-1 and terms and definitions in the standard were updated.
Then Table 1 was extensively revised. Alloys EN AC-21200 [EN AC-Al Cu4MnMg] and EN AC-43100 [EN AC-Al Si10Mg(b)] were deleted while EN AC-42300 [EN AC-Al Si7(Mg)]; EN AC-42400 [EN AC-Al Si7MnMg]; EN AC-44600 [EN AC-Al Si10Mn]; EN AC-45600 [EN AC-Al Si7Cu1Mg0,6]; EN AC-47200 [EN AC-Al Si12(Fe)]; and EN AC-48200 [EN AC-Al Si15Cu3MgFe] were added. The maximum limit for lead was reduced to 0,29 %; and Table 1 footnotes were added to and modified. Finally the chemical composition limits of the alloys EN AC-43000 [EN AC-Al Si10Mg], EN AC43300 [EN AC-Al Si9Mg] and EN AC-51300 [EN AC-AlMg5] were modified.
In Table 2, EN AC-21200 [EN AC-Al Cu5MnMg] and EN AC-43100 [EN AC-Al Si10Mg(b)] were deleted, while EN AC-42300 [EN AC-Al Si7(Mg)]; EN AC-45600 [EN AC-Al Si7Cu1Mg0,6]; and EN AC-48200 [EN AC-Al Si15Cu3MgFe] were added. As well, the mechanical properties of the already existing alloys EN AC-42100 [EN AC-Al Si7Mg0,3], EN AC-43300 [EN AC-Al Si9Mg] and EN AC-71100 [EN AC-Al Zn10Si8Mg] were modified and a new footnote was added.
In Table 3, EN AC-21200 [EN AC-Al Cu5MnMg] and EN AC-43100 [EN AC-Al Si10Mg(b)] were deleted and EN AC-42300 [EN AC-Al Si7(Mg)] and EN AC-45600 [EN AC-Al Si7Cu1Mg0,6] were added. Plus the mechanical properties of the already existing alloys EN AC-46200 [EN AC-Al Si8Cu3], EN AC-43300 [EN AC-Al Si9Mg] and EN AC-71100 [EN AC-Al Zn10Si8Mg] were modified.
In Table A.1, EN AC-46200 [EN AC-Al Si8Cu3] was deleted and EN AC-42400 [EN AC-Al Si7MnMg]; EN AC-44600 [EN AC-Al Si10Mn]; and EN AC-48200 [EN AC-Al Si15Cu3MgFe] were added. The mechanical properties of the already existing alloys EN AC-43500 [EN AC-AlSi10MnMg], EN AC-46000 [EN AC-Al Si9Cu3(Fe)] and EN AC-71100 [EN AC-Al Zn10Si8Mg] were modified.
A new Annex B was added and the former Annex B renamed to Annex C. Meanwhile in Table C.1, the same alloys as in Table 1 were added or deleted respectively. The suitability of some casting methods was revised for some alloys and some rankings of properties and footnotes were modified.
Finally the former Annex C was renamed to Annex D and Table D.1 was completely revised – completing an extensive revision of this influential standard.
