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 analysis of a new spindle for Bentley III & B50 rear brakes, detailing its material composition and hardness tests.
| Identifier | ExFiles\Box 121\1\ scan0041 | |
| Date | 12th September 1938 | |
| File M.1678. To Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} from H1/EJW. Laboratory. H1/EJW. 2/JM.{Mr Morley} 12.9.38. /1029 Bentley III & B50 Rear Brakes. Your ref. Rm{William Robotham - Chief Engineer}/AFM{Anthony F. Martindale} 2/R.{Sir Henry Royce} 1.9.38. We have examined the new spindle submitted which was quoted in your memo to be 3% nickel case-hardening steel. The depth of case on the case-hardened section was correct, and was of correct hardness. C64 (Rockwell). Hardness tests on the core varied between 232 and 277 120/2, and when tested with 3000/10 gave 197.brinell. The fracture of the core was fibrous and that of the case was crystalline. Micro examination showed that the heat treatment was not entirely satisfactory, streamers of free ferrite being present in the spindle. One of these is shewn in photomicrograph M.1678/1 of which we attach two copies. There was also an abundance of slag. Analysis revealed that the material was not 3% nickel case-hardening steel as supposed, but a steel possessing the following composition. T.C. 0.15% Mn. 0.66% Ni. 0.14% This is in the range quoted in spec.2S14 which is a low carbon case hardening steel. A section of the spindle was reheat-treated as follows. | ||