From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification for aluminium metal, outlining its chemical composition and Brinell hardness.
| Identifier | ExFiles\Box 76\3\ scan0049 | |
| Date | 26th April 1917 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. R.R. SPECIFICATION FOR ALUMINIUM METAL Silicon Max .35% Iron " .50 Zinc .10 Tin .10 Oxide of Aluminium .10 Total other impurities and metals .25% Minimum of pure Aluminium 98.6% Brinell hardness in chilled ingot as received max 42 (1" below surface) Tested by fracture at present above spec. should be quite easy to comply with | ||