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).
Proposal for testing the effect of prolonged heat treatment on Silchrome exhaust valves.
| Identifier | ExFiles\Box 54\3\ Scan218 | |
| Date | 16th May 1928 | |
| Hs.{Lord Ernest Hives - Chair} c to By.{R.W. Bailey - Chief Engineer} c to Rg.{Mr Rowledge} X4634 H16/EA16.5.28. R150. Laboratory. Re Effect of Exhaust Port Temperature on Silchrome valves. We suggest that it would be interesting to test a few exhaust valves which, instead of the usual tempering, had been given a prolonged heat at the maximum temperature likely to be reached in the exhaust port. As a result of a series of experiments on the effect of soaking Silchrome steel at various temperatures, we find that a six-hour period at 850°C would be suitable, and we anticipate that this would not lower the Brinell figure below the hardness range and should reduce the tendency for the head dimensions to alter during the first few hours of running. If you will let us have three or four valves, we will give them the necessary treatment. They should be in the partly machined state ready for the final heat-treatment. H1. HP 12EX | ||