Correct material and heat treatment specifications for semi-floating axle shafts.
| Identifier | ExFiles\Box 111\4\ scan0033 | |
| Date | 29th April 1938 | |
| HFS. Cgh {W Clough} /LM. c. Rm. {William Robotham - Chief Engineer} c. Rm {William Robotham - Chief Engineer} /Grys. c. Ds/Hay. c. BY {R.W. Bailey - Chief Engineer} //Cal. {Mr Calvert} c. Mr. Pendlebury. B.50. SEMI-FLOATING AXLE. RE: AXLE SHAFT MATERIAL. Referring to the two axle shafts GB.3604/5 for the semi-floating axle for the above car, the correct material for these shafts is the fully heat treated steel and not a case hardening variety. The Order Office happened to refer the forging for these pieces back to me, and I at once pointed out that the materials ordered were not the right type for the duty they had to undertake, and replaced the instructions for S/ZNX and S/ZNCR with S.65 nickel chrome steel, which is a 3 1/2% nickel with approximately 1% chromium, and S.28, which is a 4 1/4% nickel, 1.3 chromium steel, and I propose to make shafts in both steels as follows :- S.65, to be given the following heat treatment.- Harden in oil from 850°C. Temper between 500 to 550°C., and quench in oil. Brinell hardness - Mean figure 332. Brinell range - 321/341. S.28, to be given the following heat treatment.- Harden in air from 820°C. Temper 275°C for an hour. Mean brinell figure 386. Brinell range 376/418. BY. {R.W. Bailey - Chief Engineer} | ||
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).