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).
Notes on a visit to the Wyman-Gordon Co. plant in Harvey, Illinois to see the first forging of Merlin crankshafts.
| Identifier | ExFiles\Box 178\2\ img103 | |
| Date | 5th January 1940 | |
| NOTES ON VISIT TO HARVEY, ILLINOIS, JAN. 5/40. On Friday, January 5, Lessells and I went to Wyman-Gordon Co. plant at Harvey to see the first forging of Merlin cranks. Forgings. WG{Mr Gill - Financial Director} have divided their job into two parts. (1) One of the ingots of the first heat has been rolled into 4" sq. and this material has been used up in making various standard crankshaft forgings. Cadillac, Chrysler 8 and other cranks have been forged, and since all these rank as difficult forgings, some with integral balance weights equally as difficult to fill as the Merlin, the forgeability of the steel has been clearly established. Harold Wood considers this one of the better of the alloy steels in this respect, and superior in free-scaling properties due to the high molybdenum. Best forging temperature appears to be 2200°F.{Mr Friese} 2275°F is too high. (2) None of the VCM steel has yet been used in the Merlin dies. These have been tried out so far on stock made from broken piston rods from the steam hammers -- a nickel chomemoly. steel of generally similar properties. Several difficulties have arisen in getting the corners of the balance wts. to fill out properly. Some cold laps in the waist of the small balance weights have occurred but Wood says can be easily handled. The large balance weight at the front end has so far refused to fill out to the one corner in the lower die. The metal backs up into the tong-hold and flange. For the sake of more uniform sections for heat treat W.G. would like to add to the thickness of the flange, but fear this might increase the difficulty in filling the large balance weight. From the point of view of filling the die these sharp corners of the balance weights should be flatted back about 3/8", using a plain straddle mill operation to finish them, like the Allison crank. (The same applies to automobile crank recently by Derby, although, if made of carbon steel the difficulty of filling these will be very much less.) The balancing effect of these corners is in any case, very small. Harold Wood was confident of producing 100% forgings for the first run, with a week more of practice. He wants to see us again in two weeks, when test results on the first forgings will be nearly completed. There is nothing exceptional about the difficulties encountered which all have to do with the breakdown die. This die is always a matter for experiment. | ||