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).
Discrepancies in the material specifications and test results for model crankshafts.
| Identifier | ExFiles\Box 63\4\ scan0134 | |
| Date | 3rd October 1930 | |
| Rg.{Mr Rowledge} c.Hs.{Lord Ernest Hives - Chair} c.Hl. x4499 BY15/J.3.10.30. (B430) Model Crankshafts. ---------------- Referring to Hl's report No.M.711 of September 25th, on the above, we wish to place on record the following points:- 1/- MODEL CRANKS IN 5% NICKEL CASE HARDENING STEEL. The Tensile Test Figures given on page 5 of Hl's report are typical of the results normally obtained from material to our specification No.207C which is a special material having higher Tensile figures than our standard 5% Nickel Case Hardening Steel to Specification No.2072. It seems obvious that these model cranks were not produced from this special steel or alternatively the heat treatment was incorrect as the Brinell Figure actually obtained on the model cranks was much too low. 2/- MODEL CRANKS SUPPOSED TO BE IN S/ZNCR SPECIFICATION 236. This is entirely incorrect and the cranks were actually produced from 100 Ton Air Hardening Gear Steel and should have had a Brinell of at least 401-444. It is evident that the comparative tests are of no value as far as these two materials are concerned and should, we consider, be repeated. BY.{R.W. Bailey - Chief Engineer} | ||