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).
Casting and hardness issues of AC 9 bearings supplied by Wellworthy Ltd.
| Identifier | ExFiles\Box 115\5\ scan0255 | |
| Date | 6th March 1939 | |
| By.{R.W. Bailey - Chief Engineer} C.Hs.{Lord Ernest Hives - Chair}RM.{William Robotham - Chief Engineer} C.Hl. C.RHC.{R. H. Coverley - Production Engineer} RHC{R. H. Coverley - Production Engineer}/JWW.1/JRE.6/3/39. Re AC 9 Bearings cast by Messrs Wellworthy Ltd. We have been in communication with Messrs. Wellworthy Ltd. several times recently in connection with the AC 9 bearings that are being cast by them. The chief difficulty that they are meeting is that they cannot attain a sufficiently high Brinell figure. Representatives from Messrs Wellworthy Ltd . who have called on us on several occasions, visited us again a few days ago with a view to discussing their difficulties, and they brought with them several sample bearings which on examination shew that the required hardness figure is not attained. Analysis of the alloy AC 9 as cast by Messrs. Wellworthy Ltd. shews that the composition is correct except for the fact that the Silicon content falls .01% short of the minimum specification of .2%. At this firm the alloy is mixed to correct specification as regards composition. The Wellworthy alloy gives a Brinell figure as cast of 30, and when cast and quenched this figure reaches only 45. Our alloy gives an "as cast" Brinell of 40 to 45 and when quenched from 60 to 65. On heat treatment, for 36 hours at 190 C, the Wellworthy metal aquires a hardness of only 25 to 66 Brinell whereas | ||