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).
The examination of a Phantom III front suspension coil spring after a 100-hour test.
| Identifier | ExFiles\Box 95\2\ scan0260 | |
| Date | 8th June 1938 | |
| MARTINDALE Rm.{William Robotham - Chief Engineer} ✓ H1/EJW.1/SK.8.6.38. M.1617 Laboratory. Phantom III Front Suspension Coil Spring, C.84612, run satisfactorily for 100 hours. Further to Report M.1581- H1/EJW.2/GS.9.5.38. Examination of the surface of this spring did not reveal any cracks such as were found in the broken springs previously examined. There was a certain amount of partial decarburisation as shown in the attached photomicrograph, but this was less marked than that in the broken springs, and the free ferrite found at the surface less massive - compare with photo. M.1581/1. The hardness of the core was 418 Brinell and that of the surface 338 Brinell. It should be of interest to try the effect of eliminating this surface decarburisation by a short carburising treatment in a cyanide bath. In this connection the work done here in connection with road springs should be helpful. This was described in our Report M.1486 - H1/EJW.1/GS.3.2.38. We know that Mr. Burton of E.S.C. is interested in this method of controlling the condition of the surface and he could probably arrange to treat one or two of the springs in this way. HL/EJW. | ||