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 detailing the composition and heat treatment for nickel-chrome cast hardening steel, and a disagreement with the final tempering process.
Identifier | ExFiles\Box 153\2\ scan0141 | |
Date | 21th October 1936 | |
c. Rm{William Robotham - Chief Engineer}/Hy.{Tom Haldenby - Plant Engineer} X1300 BY/EM.6/J.{Mr Johnson W.M.} 21st, October 1936. Messrs. Ransome & Marles Limited, Newark-on-Trent. Dear Sirs, We have now heard from the Adamant Engineering Co, Limited, that the particulars of the nickel chrome cast hardening steel they use for the parts which are now to be manufactured by you, are as follows:- Carbon .10 to .20% Sulphur not more than .04% Phosphorus " " " .04% Chromium .75 to 1.1% Nickel 2.75 to 4.0% Manganese .3 to .5% Silicon not more than .3% The recommended heat treatment for this material is as follows:- Carburising at 880°C. and allow to cool down in the box. Re-heat to 880°C. and quench in oil. Re-heat to 780°C. and quench in oil. Finally temper for 20 minutes at 200°C. We most certainly do not agree with this latter operation as we are quite certain that to temper a case hardened material at 200°C. will seriously reduce the hardness of the case. We do not quite understand why it should be necessary in connection with the parts you are making, for this treatment to be applied, but presumably it is in connection with the final grinding in order to avoid cracking. Cont'd.{John DeLooze - Company Secretary} | ||