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).
Letter discussing a disagreement over the microstructure of iron used in brake drums with Ferodo Ltd.
| Identifier | ExFiles\Box 141\1\ scan0209 | |
| Date | 12th November 1936 | |
| 1180 Experimental Department 12th November 1936. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}7/AP. J.N.Langley Esq., Chief Chemist, Messrs Ferodo Ltd., CHAPEL-EN-LE-FRITH. Dear Mr.Langley, Your letter of the 9th inst. arrived simultaneously with the report of our Laboratory,on the piece of Millenite Iron which scored badly. I note that you say the iron is a "mixture of soft ferrite in large patches" whereas our Laboratory report says it is " a mixture of finely laminated and sorbitic pearlite". As these statements do not seem to agree, may we have pictures of your sections so that we can see how this difference of opinion has arisen. I further note that you say "the difficulties of reproducing an ideal structure in an alloy cast iron - of this small section - must be nearly insuperable" The idea of this ideal structure is not new to me, but formerly I have always associated it with friction characteristics, fading and so on, but now it appears you are blaming the structure for this scoring. Our Laboratory recently suggested that in our own Foundry we might make use of the thin section to introduce a slight chill into the casting to raise the Brinell (we do this with our cylinder linings.) This suggestion, also, conflicts with your statement quoted. I recently attended an address given by Mr. Sisman of the British Belting and Asbestos Co., and he stated that in his opinion changes in the ferrous mating surface of a brake had very little effect on the performance of the brake. You will remember that we tried, at your suggestion, a solid drum in 0.9% carbon steel, and this you pronounced to be no better than the Millenite drums to which you had taken exception. continued. | ||