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).
The nitrogenisation of steel process for crankshafts and cylinders observed at the Hispano Works.
| Identifier | ExFiles\Box 22\1\ Scan308 | |
| Date | 1st October 1928 | |
| Y4214 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG13.10.28 To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to RG.{Mr Rowledge} BY.{R.W. Bailey - Chief Engineer} PARIS SHOW. X3609 NITROGENISATION OF STEEL. X4469 Through Col. Hawkins and the courtesy of Mons. Lacoste we were able to visit the Hispano Works and see this process in production. It is standardised on their crankshafts and cylinders. The crankshafts are partially finished, heat treated and then completely finished before hardened. They are then heated in an atmosphere of ammonia for 50 hrs. at 500°C ± 25° and when removed have a hardened skin of ¼ mm. thickness. The bearings are then polished on a buffing wheel. The process is exceedingly simple and is carried out in a small electric furnace in the Hispano Works, ammonia being obtained from a normal oxygen type cylinder. The furnace takes 30 crankshafts or 120 cyl. liners. One cyl. of ammonia does two or three complete furnace charges. The cyl. liners are protected on the outside by tin. They are treated in the same way as the cranks but are finished ground in the bore after hardening, with a very soft carborundum wheel. This is presumably due to distortion which takes place in the hardening, though the patentees were emphatic that no distortion takes place on the majority of jobs. Hispanos are, apparently, still running whitemetal bearings but are experimenting with duralumin rods running directly on the shaft and bronze main bearings. They seem to think that these will be standardised shortly. contd :- | ||