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).
Letter specifying the heat treatment process and hardness requirements for gears.
| Identifier | ExFiles\Box 136\4\ scan0096 | |
| Date | 8th May 1934 | |
| -2- HS{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}6/KW. 8.5.34. We suggest a case of from 0.010" to 0.015" thick and that you should cyanide treat the gears at 820°C and quench in oil following with a quench from 760°C as above. However, we leave the heat treatment to your discretion. Our requirements are; that the above physical properties should be maintained in the core; that the Vickers hardness figure for the case measured under a light load of 5 Kgs. should if possible be not less than 800; and that distortion should be kept to a minimum. The gears would not be ground after hardening. Will you please let us know whether you can carry out the above work for us. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||