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 'Y' alloy pistons with a proposed new 'T50' alloy, detailing the advantages of the new material.
| Identifier | ExFiles\Box 148\3\ scan0044 | |
| Date | 19th December 1927 | |
| X2748 BY: S-to RJ. L " M.{Mr Moon / Mr Moore} L " HCF. " Rs.{Sir Henry Royce's Secretary} " Rg.{Mr Rowledge} H12/EDM.19.12.27. Laboratory. X4004 X3996 X8040 RE. FORGED ALUMINIUM ALLOY PISTONS. The "Y" alloy pistons which have been tried out are not entirely satisfactory and are expensive. One trouble is that they tend to have local oxidation flaws; they are also liable to a type of brittleness in thin sections. The primary advantage claimed for "Y" alloy is high tensile strength at the maximum running temperature. In view of the above and also as a result of tests it appears that a somewhat lighter alloy similar to the one which is being tried out for all light alloy castings on the F II engine, would be better for pistons. The following points may be noted in respect to this alloy, which has been designated "T50" :- (1) It produces much finer grain castings than "Y" alloy, and is less liable to surface oxidation. (2) It forges quite as well as "Y" alloy. (3) It can be produced of similar strength at the running temperature. (4) It is less liable to internal oxidation and brittleness. (5) It can be heat-treated at a lower temperature or at a similar temperature to "Y" alloy, giving similar results. (6) It machines well, is somewhat lighter, and is relatively good from the corrosion and heat conductivity standpoints. If required the "T50" alloy could be used for producing die-castings for pistons. Hl. IH [STAMP: RECEIVED 20 DEC 1927] | ||