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 fractured rocking shaft and a car frame, detailing their chemical composition and hardness.
| Identifier | ExFiles\Box 76\3\ scan0107 | |
| Date | 25th November 1919 | |
| R.R. 285 a (100 T) (S.F. 575, 16-4-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354. Mr Hives. H12/EB251119. Laboratory. Re one rocking shaft (fractured), and one part of car frame. Analyses. Rocking shaft. Car frame. Carbon .31 .28 Manganese .44 .47 Nickel 3.42 3.17 Chromium Nil .10 Phosphorus .037 .022 Silicon .14 Sulphur .042 The former is a rather soft Nickel Steel of a composition we do not use at present; it is possible that it is some of the material supplied by the Monkbridge Iron & Steel Co. The hardness number worked out from the formula 7C+2(Mn+Cr{Mr Cra???ster / Mr Chichester})+Ni = 6.47. According to our specification we do not permit a hardness number of less than 7.2 for the section employed for this part. The Brinell figure as received was 255. The car frame material appears to be about normal in composition, but the surface has been decarburised owing to prolonged annealing. This is, I think, the primary cause of fracture since the Brinell figure for the outside is only in the neighbourhood of 120, whereas the interior is 158. The softness of the material and the decarburisation is confirmed by a microscopic examination and also by heat treatment; under the latter test the exterior gave a Brinell figure of 340 and the interior 477. | ||