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).
Laboratory report on a failed Condor Crankshaft due to improper heat treatment after a 110-hour endurance test.
| Identifier | ExFiles\Box 76\3\ scan0103 | |
| Date | 16th April 1919 | |
| R.R. 285 A (100 T) (S.F. 575. 16-4-19. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354. R.{Sir Henry Royce} c to Expt'l c to E.H. c to Ey. H17/EB31019. Laboratory. Re Condor Crank shaft that broke after about 110 hours endurance test. Further to our preliminary report H18/EB30919. On further micro section being cut from close to the fractured part, we conclude that this shaft has not been heat treated in the sense of normal quench and temper process. As previously noted, the steel appears to have been heated to a high temperature, probably for a considerable time, for forging, and the structure produced is still evident in the broken crank, (photograph herewith at 100 diameters magnification). To confirm the lack of heat treatment, we have given the piece of broken crank the ordinary quench and temper usually employed for crank shafts, taking care to give about similar times at the various temperatures, and the resultant heat treated steel was found to be of satisfactory fracture and micro structure, ie. in great contrast to the crank as failed, which could not have given the physical tests of our specification. A Sulphur prints showing manganese sulphide and segregation is included with this note. hdb | ||