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).
Required yield and brinell hardness for gun barrels.
| Identifier | ExFiles\Box 176\3\ img127 | |
| Date | 20th August 1940 | |
| Rm.{William Robotham - Chief Engineer} C. Ve. Cgh{W Clough}/EM.4/J.20.8.40. Gun Barrels. With reference to your memo Rm.{William Robotham - Chief Engineer}8/ML.18.8.40 regarding the yield of 50 tons required on our gun barrels, we have to say that the figure of 45-50 tons yield referred to in our specification Cgh{W Clough}/EM.8/MM.26.6.40 was revised as a result of Ve's Dept. advising us that they required a yield of 50 tons. This information was conveyed to The English Steel Corporation Limited, and we are pleased to say that all 15 barrels which we have so far received from The English Steel Corporation have a minimum yield of 54 tons and the average is of the order of 56-57 tons. Some of these barrels have come out a shade on the hard side as far as brinell hardness is concerned up to 341 brinell, but we should consider this to be readily machinable and we do not consider any difficulties should arise so long as the brinell hardness of 341 is not exceeded. Cgh{W Clough}/EM. | ||