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).
Comparing S.L.V. and High Nickel Chrome plus tungsten steels for valve production.
| Identifier | ExFiles\Box 154a\1\ scan0075 | |
| Date | 8th June 1922 | |
| - 3 - | | 700°C | 800°C | 900°C --- | --- | --- | --- S.L.V. | 55 - 45 | 73 - 75 | 77 - 78 High Nickel Chrome. | 26 - 25 | 28 - 27 | 30 - 30 In view of the points raised it would be of definite interest and value to cover the ground of your experiments again, this time using the simple standard tensile test piece which would eliminate many possibilities of error involved in the use of a specially shaped test piece formed like a valve. The introduction of the high nickel chrome plus tungsten type of steel has been pushed on the basis of its higher tensile values at high temperatures, and its decreased elongation and reduction in area under such conditions, and therefore if it can be shown that this type of steel is not as good as the high silicon chrome (S.L.V.) we are at present using, it will be evident that we have nothing to gain ultimately in the use of such a steel. Our own reason for pressing for tests on the new type steel are purely from a manufacturing point of view, for even in spite of the information conveyed to Hs. {Lord Ernest Hives - Chair} by the A.I.D. Chiefs we are satisfied that at least up to the point of the finishing of the forgings for the valve there are no reasons in the production of the new type steel which are at all comparable with those which obtain with our present standard S.L.V. steel. We can appreciate that other makers have trouble from the forging stage onwards in machining, particularly as they incorporate a thread on the stem of the valve, but for the type of valve we are at present using the machining difficulties are very little higher, if not less than those encountered at present, and I am basing this statement upon the experience we have had in machining the Kayser Ellison and Firth types of special steel in the Experimental Department. If a thread has to be cut or a small hole has to be drilled, then the austenitic steel will unquestionably be difficult to handle, but in the absence of these particular features we do not anticipate any real difficulty. In any case all that has been pressed for is to give the new type steel a serious test in comparison with the S.L.V., and then assuming that the two types of valve steel stand up equally well in the engine one would certainly prefer the new type steel for production. BY. {R.W. Bailey - Chief Engineer} [handwritten initials] | ||