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 sheet detailing the chemical composition of two types of valve materials, S.80 and KE-965.
| Identifier | ExFiles\Box 126\4\ scan0133 | |
| Date | 18th May 1936 guessed | |
| Specification of Valve Materials. S.80 KE-965 Carbon Max. .25% .4 to .45% Manganese 1.0% .6 to .8 % Silicon 0.50% 1.25 to 1.5% Sulphur 0.04% 0.04% Phosphorus 0.04% 0.04% Chromium 16 to 20% 12.0 to 13.0% Nickel Not less than 1% 12.0 to 14.0% Tungsten - 2.0 to 2.5% | ||