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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).
Analysis of a fractured American crankshaft from an 'Eagle' engine.

Identifier  ExFiles\Box 38\6\  Scan046
Date  4th December 1918
  
EH2/LGW 4.12.18.
4th December 1918.

To R.{Sir Henry Royce} from EH.
c. to CJ.
c. to OY.
c. to Na.{Mr Nadin}

RE FRACTURE ON AN AMERICAN CRANKSHAFT X.3381.

Attached herewith are photographs which shew the fracture of this crankshaft. We have had 2 other "Eagle" crankshafts break in identically the same way and in the same bearing which is No.5 It is possible that if the screwed plugs are forced in very tight, they might tend to start the fracture. Below is Mr. Hall's report on the steel:-

ANALYSIS.

Carbon. .41
Manganese. .66
Chromium .89
Phosphorus .017
Sulphur. .037
Nickel. 1.27

From the analysis this steel is not, I consider very suitable for crankshaft work, since it would either require water hardening or oil hardening at a higher temperature than desirable for crankshaft material. There were evidences of weakness in the vicinity of the fracture.

The brinell hardness was found to be 302. The fracture was not so fibrous as generally obtained with a higher percent-age of nickel.

EH.
  
  


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