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).
Issues of oxidation and electrolytic action when casting iron liners into aluminium brake drums.
| Identifier | ExFiles\Box 121\1\ scan0400 | |
| Date | 20th December 1940 | |
| Mr. Gresham (Osmaston Road Laboratory) Copy to Rm.{William Robotham - Chief Engineer} & MHR.{M. H. Rigby} Brakes 1027 This is to confirm our recent telephone conversation. In the past we have shrunk cast iron liners into aluminium brake drums. This involves machining accurately both the drum and the liner. In order to get the cost down we want to cast the iron liner in the aluminium drum. Before this can be done successfully, two problems must be solved. They are:- 1. The oxide layer between the iron and the aluminium must be prevented from forming during casting and use. This layer formed in service on the iron rings which were shrunk in hubs except when plating was resorted to. 2. Mr. Wheeler states that electrolytic action between the iron and the aluminium is liable to occur. The reason why we do not want an oxide layer between the iron and the aluminium is that the liner temperature would rise unduly during braking. We would like you to recommend us a plating which would prevent oxidation and electrolytic action and which would if possible give a close union between the iron and the aluminium. Rm{William Robotham - Chief Engineer}/GB G.B. | ||