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).
Micro-examination report on the wear and pitting of a chromium-plated cylinder liner.
| Identifier | ExFiles\Box 127\3\ scan0118 | |
| Date | 22th September 1936 | |
| Spare Copy Micro-Examination Report. M.1193. To Hs{Lord Ernest Hives - Chair}/Wd.{Mr Wood/Mr Whitehead} HL2/AG.22.9.36. Laboratory. RE: CYLINDER LINER E.47264 FROM UNIVERSAL SINGLE CYLINDER UNIT. (Your ref: Hs{Lord Ernest Hives - Chair}/Wd.{Mr Wood/Mr Whitehead}9/GB.5.9.36) This liner was chromium plated in the bore by Messrs. Durions, subsequently being annealed at 200°C. for 1 1/2 hours. After running for 153 hours water-cooled it was found to be worn in the usual place at the top of the stroke and to have vertical scored marks in the plated surface as well as numerous small pits. A section from the top of the liner about 3" wide and 5" deep was submitted for examination of its surface condition. It was also desired to establish the amount of wear which had taken place. The attached blueprint gives details of the various regions referred to in connection with the photomicrographs taken, and also the thickness of the chromium plate at several points. In the most worn regions the surface of the chromium was highly polished, but elsewhere a large number of small pits and circumferential lines gave it a duller.appearance. These small pits were not due to breakdown in running, since at the bottom of many of them could be seen clearly the original nodular surface of the chromium plate. It was evident that the pits were originated by depressions in the grinding marks in the steel base, the surface contour of the latter having been reproduced in the chromium plate. Thus the only areas free from pits were those in which the wear had been sufficient to get to the bottom of the pits and obliterate them. Photomicrograph No. Al,495 was taken in one of the least worn areas and shows the connection between the pits and the circumferential marks. contd. | ||