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).
Data sheet for Hiduminium R.R. 56 stampings, detailing physical properties, heat treatment, and performance metrics.
| Identifier | ExFiles\Box 116\2\ scan0132 | |
| Date | 22th December 1939 guessed | |
| Data Sheet No. 25 HIDUMINIUM R.R. 56 STAMPINGS PHYSICAL PROPERTIES. SPECIFIC GRAVITY ... 2.75 HEAT CONDUCTIVITY ... 0°C.—100°C.—0.43.C.G.S. Units. CO-EFFICIENT OF THERMAL EXPANSION ... 20°C.—100°C. 22.0 x 10⁻⁶. WOHLER FATIGUE ... ±10.0 tons per sq. inch at 40 million reversals. HEAT TREATMENT. Soak the stampings at 530°C. ±5°C. for not less than two hours and quench in water at 70°C. to 100°C. Age for 10 to 20 hours at 165°—175°C. and again quench in water. An alternative ageing treatment of 2 hours at 200°C. can be given, but this must be carefully regulated, and the time of bringing up to heat closely watched, according to the size and bulk of the stampings. REPEAT IMPACT FATIGUE FIGURES—Refer to Data Sheet No. 21. TENSILE TESTS. 1¼" Square bar, heat treated, and machined to 0.564 inches on 2" gauge length. .1% Proof Stress Tons per sq. in. 20 to 22. Yield Point Tons per sq. in. 24 to 26. Ultimate Stress Tons per sq. in. 28 to 30. Elongation % on 2" 10 to 20. Brinell Hardness 129 to 138. TENSILE STRENGTH AT ELEVATED TEMPERATURES. Temp. of Test NORMAL 100°C. 150°C. 200°C. 250°C. 300°C. 350°C. Ultimate Stress Tons per sq. in. 29.0. 27.0. 25.5. 24.0. 20.0. 16.75. 8.50. BRINELL HARDNESS AT ELEVATED TEMPERATURES. Temp. of Test NORMAL 100°C. 150°C. 200°C. 250°C. 300°C. 350°C. Hardness No. 138 130 120 107 80 37 16 Recovery Value After Cooling — 138 138 138 120 85 66 HIGH DUTY ALLOYS LTD. SLOUGH Telephone : SLOUGH 21201 (6 lines) Telegrams : “ ALLOYS, SLOUGH ” P.T.O. | ||