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).
Report comparing low temperature treatment versus quenching from the die for Bentley pistons to determine methods for increasing longevity.
| Identifier | ExFiles\Box 86\2\ scan0162 | |
| Date | 23th November 1933 | |
| Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} E.{Mr Elliott - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} C. Hl. Y236 BY.19/G.23.11.33. BENTLEY PISTONS. ---------------- With reference to the variation which has been found in practice between the Bentley pistons which are die cast, allowed to cool off and then given a low temperature treatment which has been our general standard practice, and those which have been given a quench from 450° by carrying the pistons in a special oven to permit them to cool to this figure after die casting, we have, as suggested carried out a large number of tests on Stanton test pieces treated by both methods, and the results show that as a result of the treatment the quenched pistons should have an increased life. The average figures over a number of tests are :- (a). Low temperature treatment, our present standard practice. 615 blows. (b). Treatment with quench from the die 1314 blows. As in practice the results obtained do not agree with the figures it is evident that the difference must lie in the condition of the piston as die cast, it being evident that incipient cracks or over-stressed areas must exist in the pistons as taken from the die, and such areas are re-acted upon by the quench. We do not, of course, suggest that the results given above indicate that the quenching treatment should be adopted, but it certainly does indicate that we should consider our die casting process, which is a matter that I will give some attention to in this connection. BY.{R.W. Bailey - Chief Engineer} BM | ||