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 from The Morgan Crucible Company detailing pump gland design, leakage, and the chemical composition of F.H. stainless steel.
| Identifier | ExFiles\Box 149a\1\ scan0118 | |
| Date | 4th August 1937 | |
| EH 2781 -2- To Rolls-Royce Ltd., DERBY. The Morgan Crucible Company, Limited. 4th August, 1937. large number of designs which have run with the ball-race approximately 1" from the dry side of the gland; a leak hole is provided between the two, but is only necessary in order to ensure that a few drops of water which may leak through the gland during the initial bedding in period, may be allowed to escape without passing through the ball-race. We are enclosing our Sketch No.100/303, being a design which has now been in use for some six years on the L.P.T.B. oil and petrol buses. Leakage on these pumps is unknown. 4). After experimenting with a number of different types of stainless and other steels, amongst which Nitralloy was included, we have found that Messrs. Thos. Firth & John Brown Ltd., Atlas and Norfolk Works, Sheffield, 1, can supply the most satisfactory steel. This steel, which is called F.H., has the following analysis:- Carbon .25% to .35% Silicon Not over .60% Manganese " " .50% Sulphur " " .05% Phosphor " " .05% Chromium 12 to 14.50% * We do not claim that this steel is the best stainless steel made, but that its combined qualities of resistance to corrosion and toughness have been found to be the best when the material is run in conjunction with a carbon seal. This material is used by the L.P.T.B. omnibuses referred to above, and we have never had a complaint of corrosion. 5). We regret that it would appear we misunderstood the meaning of optimum sealing pressure. We think it would be better to clarify the situation as follows. | ||