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).
Experimental heat-treatment process for a roller part and establishing standard procedures in the Hardening Shop.
| Identifier | ExFiles\Box 153\1\ scan0268 | |
| Date | 19th April 1939 guessed | |
| 2. We found by experiment that it was necessary to increase both quenching temperatures by 10C in order to acquire the required fine grain on the case and core of this roller. The whole batch was brought back and re-treated under the same conditions with satisfactory results. Tests on finished roller from this batch are satisfactory, and we understand that 3 1/2 times the normal load on this part was required to break same. Our practice in the Hardening Shop with any new job, is to find by experiment on individual pieces or very small batches, the correct conditions i.e. times and temperatures before we proceed with the bulk supply. A card index is then made, giving all particulars of heat-treatment, so that the necessary information is available at any time. This is so with every part passing through the Hardening Shop. Owing to the urgency of this batch and the assurance of Messrs Hoffmans' representatives that they used the normal temperatures the experimental heat-treatment was not carried out, also no trouble was anticipated in view of the fact that we produce very many parts such as gears, gudgeon pins etc, in this material. This particular part is now card indexed for carburizing and heat-treatment, together with instructions also on the card, that a fracture test shall be carried out on every furnace batch. Samples of both satisfactory and unsatisfactory fractures have been given to the Hardening Shop Foremen, so that they will know | ||