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).
Laboratory report comparing the corrosion resistance of different aluminium alloys, particularly R.R.50, under various conditions.
| Identifier | ExFiles\Box 148\3\ scan0075 | |
| Date | 10th May 1933 | |
| [handwritten]X2748. To H.{Arthur M. Hanbury - Head Complaints} C. WDP. C. Hs.{Lord Ernest Hives - Chair} C. PX. HLL/AG.10.5.33. Laboratory. Re: Aluminium Alloys. See E2/H.P 6.5.33 [handwritten]i.e. It appears that under ordinary conditions of service, under atmospheric, boiling or sea water conditions, R.R.50 castings give better resistance than any other commercial alloy of fair strength. R.R.50 is considerably better for instance than the 8% copper or high zinc alloys previously used for similar purposes; the amount of corrosion produced being markedly less, particularly when given the oxidising treatment which has been used for engines that have been accidentally submerged in the sea. When cast iron or steel is also present under boiling conditions it is practically impossible to avoid considerable corrosion product with any alum alloy unless [strikethrough]surface[/strikethrough] protection of the metallic surfaces or control of the quality of cooling water (by softening etc.) be resorted to. With respect to outboard motor boat engines we do not know of any outstanding casting alloy that has been used in the cooling system. Birmabright is not a good casting alloy its use has been chiefly for hull construction and similar purposes (rolled sheet etc.) A casting alloy is now being tested here under various conditions, boiling with and without sea water present. This alloy is better for casting than Birmabright, is stronger and keeps a very good surface in sea spray (cold) in the rolled heat-treated condition. When completed we will give you a report on these tests. HL. [handwritten]He. | ||