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).
The condition of a Nitralloy steel crankshaft exhibiting small pits.
| Identifier | ExFiles\Box 154a\1\ scan0192 | |
| Date | 24th January 1930 | |
| Hs.{Lord Ernest Hives - Chair} c. Wor.{Arthur Wormald - General Works Manager} c. Rg.{Mr Rowledge} c. Hl. X4469 BY2/G.24.1.30. NITRALLOY STEEL - RE CRANKSHAFT WITH SMALL PITS. I had Mr. Mannock, the Director of Nitralloys Limited, at the Works yesterday afternoon, and submitted to him the crank which is under discussion, which Hl. had fixed up with a microscope in position for examination in the Laboratory. Mr. Mannock is very emphatic that the condition of the shaft is not such as to affect either its strength or its good qualities for running in bearings. He tells us that this condition of the steel is the common condition on the Continent, but that it is the exception with steel produced by Messrs. Firths, although as in this case forgings do occasionally show this particular characteristic. Mr. Mannock informs us that this type of steel is of necessity subject to this fault in a greater or lesser degree. He confirms our views that it is due to the aluminium used as an alloy in the steel acting as a de-oxidizer where the steel has not been carried to the limit of de-oxidation, and which small microscopic pin pricks are quite isolated from one another do not affect the strength of the steel, and no ill-development can occur owing to their presence. At the same time every effort is being made to control the steel better to ensure the absence of this particular feature in future. We have instructed the Experimental Department that they are at liberty to use the crankshaft. BY.{R.W. Bailey - Chief Engineer} | ||