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).
Letter to Toledo Woodhead Springs Ltd. regarding methods for improving spring endurance and corrosion resistance.
| Identifier | ExFiles\Box 154\2\ scan0112 | |
| Date | 14th July 1938 | |
| -3- 14th. July, 1938. Messrs. Toledo Woodhead Springs Ltd., Sheffield, 1. We have ample evidence that the information as outlined above is correct, as be merely insisting upon :- (a). Grinding the plates to remove decarburisation. (b). Plating the leaves with cadmium, we raise the endurance of a spring on our bumping test from 17 hours to over 100. The condition of the springs which gave 17 hours was the normal spring as bought in the open market. The springs, which gave 100 hours were those treated according to our instructions by plate grinding and cadmium plating. In producing the cadmium plating, however, we arranged a scheme by which the need for acid etching or electrolytic cleaning was entirely eliminated. Either of these processes are definitely dangerous and seriously shorten the life of the springs. In regard to the question of protection from corrosion, the oxides produced by high temperature conditions can, by suitable treatment, be all converted into the magnetic oxide, which if it covers a plate completely gives 100% protection, and it is possible in my opinion by a straight treatment of the plates to achieve this end in a forged plate without etching or plating, but it will not be achieved by an odd experiment or a casual interest, it must be a prolonged effort with a determination to achieve the results. It is well known that today washing boilers are produced in pressed steel, and protected by a treatment which produces magnetic oxide of iron in a regular thickness over the face of the material. The method is quite effective, as in my own house I have a washing boiler of this type, which has been in service for 20 years and is still corrosion proof, and leaves no oxide stains upon linen or cotton. The question of protection by the production of magnetic oxide is a common process in connection with the manu- | ||