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).
Summary of a paper on the phosphate treatment process, 'Granosealing', for piston rings.
| Identifier | ExFiles\Box 148\1\ scan0037 | |
| Date | 1st January 1939 | |
| C.F.S. File 1256. I.A.E. AUTOMOBILE RESEARCH COMMITTEE Research Department, Great West Road, Brentford, Middx. No. 9225. Class 256, 92. January, 1939. Phosphate Treatment of Piston Rings ------------------------------- W.H. Spencer, Steel, December 5, 1938, pp. 60-62. ------------------------------- The author's Company (Sealed Power Corp.) tried various non-ferrous platings and coatings in order to reduce the scuffing of piston rings. It was found that non-ferrous coatings would sometimes help a little but the cost was excessive and the change in dimensions due to plating was a serious draw-back. Experiments were made with a phosphate surfaced ring which was found entirely satisfactory and the process is now termed "Granosealing". On a treated surface oil spreads quickly and wiping does not remove it readily. The surface is first degreased and gray iron or steel parts are then placed in the treatment bath. Hardened steel or chilled iron are etched in acid before treatment. The bath consists of diluted phosphoric acid containing manganese and saturated with iron. The length of time that iron remains in the solution before action ceases varies from 5 - 30 min. For piston rings, a solution is used having about 2% free acid at a temperature of 210°F.{Mr Friese} Evolution of gas ceases in about 10 min. for a piston ring. The part is then washed in water and dipped in a soluble oil solution. The minimum coating used is about 0.00025 in. A plant is illustrated which will process about 50,000 rings in an 8-hour shift. Results are given of a wear test which showed that, on a camshaft, the respective wear of plain and phosphate-treated specimens was 0.0095 in. and 0.0005 in., while dynamometer tests on piston rings showed a gap change of 0.015 in. and of 0.003 in., respectively. C.G.W. | ||