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).
Heat treatment processes, material selection, and stress testing for steel springs.
| Identifier | ExFiles\Box 80\3\ scan0115 | |
| Date | 7th March 1912 guessed | |
| (3) We might also try to heat treat springs ourselves to give better results. Heat treat in the usual way, viz. lowest temperature which gives correct hardness. Tempering consists of letting down by reheating it to, say, 300º C. (increase this until permanent set is obtained). I suggest that to let down we should try - a.{Mr Adams} Oil bath at highest temperature. b. Salt bath at lowest temperature. Springs should be capable of being easily filed after tempering. Let me have particulars of heat treatment found necessary. Different qualities of steel could be tested. The steel which gives the best results can be ascertained on the test rig. Poldi and several makers say that chrome and vanadium chrome steels are superior for this purpose. The stress on the springs could be increased by stages. Having obtained a spring which will stand its tests on the rig when running under normal conditions, washers (at the top) could be fitted or some such means- (if the space between the convolutions will allow it) so as to increase the set and, therefore, the maximum | ||