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).
Discussions and actions on material hardness testing and heat treatment for bearings and bushes.
| Identifier | ExFiles\Box 115\5\ scan0176 | |
| Date | 9th November 1936 guessed | |
| -2- 5 mm. ball at 125 kg. load, as in his opinion this gave rise to error, but I interposed a remark here which rather set this aside, as I pointed out that we were checking with a very small ball on the Rockwell machine, but obtained figures which were comparable with H.D.A. Therefore there was no point as regards the machine for checking, or the size of ball, which might affect the Brinell hardness. Mr. Hall then suggested that probably going to 182°C instead of 180 would give us the hardness figure, but again I was able to produce our figures which showed that we were going to 194°C, and even after 3 heat treatments still had bearings which were below the specification and hardness figure. To overcome this and begin to get down to the trouble, we are to cast a number of bearings from material which is known to be definitely inside the specification, and will send one-third of these bearings to H.D.A., one-third to Rolls Royce, and retain one-third here, and each of us will heat treat bearings to the specified 180°C. for the two treatments of twelve hours, and compare Brinell hardness figures. Further, we brought away from Rolls, two bushes for Aero Engines and one for the Bentley car, not machined, which we cut in half, and H.D.A. and ourselves will each analyse the material and heat treat the Aero Engine bushes to see what hardness figure we get, and | ||