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).
Alloy casting issues, potential solutions, deliveries, and anodising experiments.
| Identifier | ExFiles\Box 86\2\ scan0252 | |
| Date | 5th September 1934 guessed | |
| - 2 - The cause is associated with the rapid rate of freezing of RR.53, and they do not occur in 122 alloy. After adopting every conceivable artifice to avoid this occurrence, we have concluded that it is not possible to prevent it in the foundry, and we are, therefore, casting the flutes solid so as to avoid the change of section, and will produce the necessary reduction in area at this point by machining. This should result in sound metal at this point and should obviate the apparent failure. With regard to the cracks in the 122 alloy, if these are still of the type which commence from the drilled hole at the top of the flute into which we run the heat-break sawcut, and if our experience in other directions can be reproduced on your piston, we are fairly satisfied that these can be avoided by slightly altering the position of the drilled hole and its size, and by running a sawcut into it differently. The writer would explain this small alteration next Monday and we are carrying it out on the RR.53 pistons we have in progress. On the subject of deliveries, we despatched to you on the 3rd by post, a further set in 122 alloy, which we had been holding for grinding and which we finished off to the dimensions agreed on the telephone. We have also some 24 RR.53 castings to have machined flutes, as already indicated, in progress, and a set of these should be available early next week. On the subject of anodising, we have received examples of experiments carried out on some scrap castings in RR.53, which are distinctly interesting, and from such tests as we are able to subject the specimens, there is no doubt that a reasonably hard and definitely absorbent surface has been produced. On our instructions, the specimens were dipped in hot Castrol XL oil after anodising, and there is no question of the absorption of lubricant, which, as far as we can see, should give all the effects claimed by the Alumilite people. For your information, the process has been carried out by:- S. R.{Sir Henry Royce} Sheppard, "Trafalgar Works", Station Road, Merton Abbey, S.W.19. | ||