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).
Specification for mechanical properties, heat treatment, and nitrogen hardening of parts.
| Identifier | ExFiles\Box 146\1\ scan0119 | |
| Date | 1st March 1930 guessed | |
| D.T.D.87.-2. 2. MECHANICAL PROPERTIES. - The mechanical properties of the material before nitrogen treatment shall comply with the following: Maximum stress not less than 55 or more than 65 tons per square inch. Elongation not less than 17 per cent. Izod value not less than 35 ft.lb. Brinell hardness not less than 241 or more than 302 (3.90 mm. and 3.50 mm.) Nicked fracture as required in the latest issue of B.S.Spec.S11. 3. BARS AND BILLETS FOR FORGINGS AND DROP FORGINGS.- In addition to the mechanical tests specified in the latest issue of B.S. Specification S.11 for bars and billets for forgings and drop forgings, each bar and billet shall be subjected to the nicked fracture test. 4. HEAT TREATMENT. (a) Bars for machining and forgings and drop forgings shall be delivered in the softened condition unless otherwise specified on the order. (b) all parts shall preferably be rough machined before heat treatment. (c) all parts and all mechanical test samples shall be hardened by heating to a temperature of 900°C. and quenching with oil. They shall then be tempered by heating to a suitable temperature of not less than 600°C. and cooling in air. (d) When annealing is necessary to remove stresses which may have been set up by machining or forging and which might lead to distortion during nitrogen treatment, the parts shall be heated to a temperature of 525 to 550°C. for not less than 4 hours and slowly cooled. ------------ SECTION II. Nitrogen Hardened Parts. 5. MATERIAL. - The parts shall be made from bars or forgings which have been inspected and passed as complying with Section I of this Specification. 6. FREEDOM FROM DEFECTS. - The parts shall be free from defects. 7. NITROGEN TREATMENT. - The parts shall be nitrogen hardened by an approved process. | ||