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).
Hardening processes and lead bronze bearings, including a lead/copper phase diagram.
| Identifier | ExFiles\Box 174\2\ img107 | |
| Date | 11th April 1937 guessed | |
| -3- TOCCO can give a Brinell of 600. The process is being extended to include cams on camshafts and Shardlow have equipment. I suggest we get some of their stuff on singles as it is such a simple process compared with nitriding, and we don't know what we gain from the extra 300 Brinell of nitriding, particularly with some of HL's bearings. Cleveland Graphite Bronze are turning out a very fine job in lead bronze bearings. They cast continuously on to a 0.050 strip of mild steel and quench immediately. The strip is then cut to length and bent to form half bearings and broached to size. This method of casting and photographs they showed us gives a finer lead separation than that obtainable by the Allison or centrifugal processes. Further, they can get in up to 40% lead. This might be well worth trying on the chassis. The diagram for lead/copper mixing is this :- [DIAGRAM: A phase diagram for lead/copper mixing. The Y-axis shows temperature in Celsius with points at 955°C, 1085°C, and 1610°C. The X-axis shows percentage, with points at 0, 37%, and 100. The diagram shows a region of 'MUTUAL SOLUTION' at higher temperatures and a region of '2 SEPARATE LIQUIDS' below it.] Their quick quench from the unshaded region gives them the desired mixing. They recommend 35% Pb. They cast at 2200°F (B2/L) 1800°F S/M shell. | ||