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).
Analysis of wear, cracking, and corrosion on a chromium and nickel-plated liner.
| Identifier | ExFiles\Box 127\3\ scan0119 | |
| Date | 14th September 1936 guessed | |
| -2- Regions of considerable wear are shown in A1,493 and A1,494. Note the absence of pits and the presence of a system of cracks. The liner was not examined by us before running, but we understand that it was finished by honing the chromium plated surface. This would almost certainly hide the small pits and lines which would only show up when the surface became more polished with wear. There does not appear to be any obvious connection between the vertical scoring of the surface and the pits just discussed. The plating was of normal section on each side of the scored marks - see A1,496 (cross section), and examination of the surface where one of these marks was just starting showed a number of cracks of which those which were more or less transverse to the path of the piston showed breaking down of the chromium at their lower edges. - A1,500. Our measurements show that the local wear at the top of the liner agrees very nearly with the wear in the same part of an unplated liner over an equivalent period of running, as determined by the Experimental department's measurements. In view of this it was agreed with Mr. Royce that further investigation into the breakdown of the chromium plate should not be made at present. The flange at the top of the liner was cracked in the direction of the grain - See A1,497. It will be observed that in the region of this crack the nickel plate has been machined away from the underside of the flange and in the radius - see blue print - and that there has been deep corrosion of the steel. At the same time deep local pits have formed at several places beneath ribs where the nickel has failed to protect the steel. In this connection it will be of interest to note that a Kestrel liner chromium plated on nickel plate has successfully resisted corrosion for fifty hours up to the present, although glycol cooled. Hl. Photomicrographs Nos. A1,493 - A1,497 and A1,500 att. Also blueprint. | ||