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).
Heat treatment and tempering tests on metal test pieces, including stress and hardness results.
| Identifier | ExFiles\Box 132\1\ scan0024 | |
| Date | 18th April 1927 guessed | |
| - 11 - cooled in air. Re-heat treated to 850°C., for one hour and cooled in air. This prolonged heat treatment was possibly too extended, but experimentally it was borne of anxiety to make sure that the primary cementitic structure should be thoroughly broken down. Micro-examination proved that this had been effected, but by what excess of heat treatment is not known. This, however, could be easily established. The test pieces were tempered at different temperatures, and the ultimate tensile strengths determined to ascertain the marginal effect of heat-treatment. | Test Piece. | Treatment. | Size. | Max. Stress Tons per sq.inch. | Elong. | B.H.N. 10/3000. | |---|---|---|---|---|---| | W.1.) | Temp. for 3 hours at 550°C, | 1" x .564 | 61.6 | - | 375. | | W.2.) | air cooled. | | 63.2 | 1.0 | 375. | | W.3.) | Temp. for 3 hours at 600°C. | 1" x .564 | 59.8 | 1.0 | 341. | | W.4.) | air cooled. | | 55.76 | - | 341. (Flaw). | | W.5.) | Temp. for 3 hours at 650°C. | 1" x .564 | 47.8 | - | 302. | | W.6.) | air cooled. | | 48.4 | 1.0 | 302. | | W.7.) | Temp. for 3 hours at 700°C. | 1" x .564 | 27.6 | - | 255. (Flaw) | | W.8.) | air cooled. | | 42.6 | 1.0 | 255. | Handwritten: Youngs Modulus. Limiting Fatigue Resistance } not complete | ||