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 Ford Motor Company detailing steel composition and heat treatment suggestions.
| Identifier | ExFiles\Box 126\3\ scan0067 | |
| Date | 3rd May 1934 | |
| -2- Carbon .38/.42% Manganese .65/.80% Chromium .90/1.1% Silicon .10/.20% Phosphorus .03% max. Sulphur .04% max. The normalising temperature for such a steel is between 1650-1750 deg.Fah. followed by a slow cool. Heat treatment figures 1500 deg.Fah. in cyanide (25% Cn{Mr Chamberain} content) for 45 minutes. Quench in oil, and strain draw in oil at 400 deg. Fah. This will give a file hard surface and a Rockwell hardness of between 48/53 "C" scale. We would suggest for a steel of the high nickel content of S.A.E. 3440, that the following treatment would prove suitable. Normalise between figures 1550 and 1650 deg.Fah. Re-heat to 1250 to 1300 deg.Fah. cooling slowly in furnace. Machine, re-heat to approximately 1450 deg.Fah. in cyanide oil quench and draw to the required hardness. As a guide 800° Fah. temper should be approximately equal to 350 Brinell, and giving approximately 250 Brinell at 1200 deg.Fah. Further, we suggest that where cost is not a dominant factor, the introduction of Molybdenum will give a vastly superior steel for sever shock loading, and eliminate completely all dange of temper brittleness. With kind personal regards, Yours sincerely, FORD MOTOR COMPANY LTD. (signed) A.R. Smith. General Manager. Skin hardness. 850 Vicers Brinell. | ||