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 analysis of bearings, discussing magnesium loss, material defects, and recommending a standardized hardness test.
| Identifier | ExFiles\Box 115\5\ scan0147 | |
| Date | 12th October 1938 guessed | |
| - 2 - there is any loss in magnesium, particularly in view of the fact that Mr. Richards opinion seems to be that by fluxing excessively we shall get a bigger loss in magnesium due to exidation. We are analysing the bearings we have retained, and Mr. Richards is looking into theirs, and he will let us have a report. Here I would stress the point that we must insist that H.D.A. should let us have reports on these matters, as my own impression is that we seem to have very little in writing and apart from the occasional 'phone messages we have nothing in the way of reports from H.D.A. on the various bearings we have sent them to show how we are progressing, as although we certainly have possibly one or two reports, they do not cover the number of times we have sent bearings to them for their views. In the case of this last report over the 'phone, that bearings from melt 21 were down to .55% magnesium, I have not so far seen this in writing from H.D.A. Concerning bearings which have already been produced, which were the subject of a discussion, samples were examined under the microscope, by Mr. Richards, and on one of them there was quite a quantity of porosity, which was inter-granular, and also in Mr.Richards' opinion showed a possibility of Copper segregation, which showed up the grain boundary. This is a point which he is going to investigate on some of the bearings he has taken back, as it may be the possible explanation of bearings which appear to be harder one side than the other, that is, they are harder on the runner side than on the side remote from the runner. In checking the hardness of these bearings, Mr. Richards is of the opinion that the Rockwell test is most unsatisfactory, and that to obtain satisfactory readings which are really reliable it should be done on a Brinell machine. He recommends a Brinell machine of 125 kg. load, with a 5 mm. ball. This information has already been passed to Mr. Hayward to obtain quotations in respect of this Brinell machine, so that we shall be on the same basis of checking as H.D.A. and Rolls-Royce. | ||