Brittleness of springs caused by cadmium plating and suggesting heat treatment as a solution.
| Identifier | ExFiles\Box 30\6\ Scan005 | |
| Date | 29th December 1927 | |
| Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} c. Wor. {Arthur Wormald - General Works Manager} c. Mx. {John H Maddocks - Chief Proving Officer} c. Hl. X1360 BY7/G.29.12.27. [STAMPED] RECEIVED 29 DEC 1927 re CADMIUM PLATING. With reference to the list of parts which you suggested for cadmium plating, I have instructed all these with the exception of the springs. I have always had an antipathy to plating any springs, as my experience has been that springs so treated are very apt to develop brittleness, possibly from hydrogen inclusion. In some recent experiments carried out by Mx. {John H Maddocks - Chief Proving Officer} in cadmium plating, certain springs treated in this manner failed, although they had never failed previously under service conditions. Brittleness from hydrogen inclusion can be eliminated by giving the pieces a fairly long treatment at a high temperature, say half an hour in hot oil at 150°C. If it is thought desirable to try road springs or helical springs one would much prefer to carry out experiments on a road spring on the bumper after we have settled the durability of a particular type of spring, and helical springs as valve springs on the test rig, but in both cases it would certainly be necessary to give them the special heat treatment referred to. [HANDWRITTEN] & The springs were included without my knowledge By BY. {R.W. Bailey - Chief Engineer} | ||
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).