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).
Metallurgical processes, heat treatment, and mechanical test requirements for steel supply.
| Identifier | ExFiles\Box 170\4\ img045 | |
| Date | 24th August 1940 guessed | |
| - 2 - processes, but must pass macroetch requirements as regards inclusions. Sources of supply in order of merit as they see it is Midvale Steel (Dr. Frevert), National Forge (Mr. Harrington), Republic Steel (Dr. Archer) or Bethlehem Steel (Mr. McKinney). The names in brackets are the metallurgical people who know the technical requirements of the Arsenal. 3. Metallurgical The macroetch disc is taken from the breech end of the forging and for the above size may be one inch thick. This after polishing and etching must meet the usual requirements as regards inclusions. 4. Heattreatment To obtain the above physicals Watertown recommend a high temperature normalize at 1900/2000°F followed by O.Q. from 1650°F and tempering at 1150°F.{Mr Friese} An intermediate annealing operation is not recommended. 5. Mechanical Two tensile tests are taken from the above macro section and are transverse in nature. Two additional longitudinal tensile tests are taken from the front end of the barrel. The transverse properties must give the following minimum values: Y.P. (.01% Set) = 95,000 to 110,000 lbs/in² Reduction Area 45% Test bars .357 in. diam. x 1.4 in. O.L. The transverse test bars are so taken that the outside of the bar is in a location corresponding to a tangent to the finished machined bore diameter. Typical test values were as follows: Y.P. = 110,000 lbs/in² = 134,500 lbs/in² e = 18% q = 58.9% 6. RifleBarrels As regards rifle barrels Watertown prefer S.A.E. 4140 which is giving good results. 7. Conclusions With above data you will be able to go ahead and obtain prices so that the letter of Rm.{William Robotham - Chief Engineer}2 of July 17 can be answered. We do not recommend two steels but a single steel for both sizes. | ||