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).
Page 2 of a letter from Ford Motor Company detailing steel composition and heat treatment recommendations.
Identifier | ExFiles\Box 136\4\ scan0091 | |
Date | 3rd May 1934 | |
-2- 3.5.34. 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. | ||