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 report on the Brinell hardness and chemical analysis of Firth's Silchrome valves.
| Identifier | ExFiles\Box 54\3\ Scan213 | |
| Date | 27th September 1926 | |
| HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer}26 He Mr. Robotham XLH6324 A now spec. This analysis conforms, the brinell is OK although on the lower limit. ARH H13/EA24.9.26. Re Firth's Silchrome Valves. 2.0 27/9/26 By Laboratory. Report No. L551. 27 SEP The Brinell hardness of the two Silchrome valves sent in by you was found to be 255, as was the case with the previous valve submitted by the Exptl. Dept. The analysis of one of the two valves submitted by you was as follows :- Carbon -------- 0.43 % (.40-.5) Manganese ------ 0.41 % (.4-.6) Silicon -------- 4.00 % (3.5 to 4.25) Chromium ------- 8.57 % (7.5 to 8.5) 255-286 (By) does this conform with our specification for Firth's valve steel (Brinell low?) H1. He RECEIVED By 24 SEP 26 | ||