Gotta give the gentleman some credit.
Major J. W. "Jim" Houlden CD, Winnipeg Light Infantry of Canada
https://www.queensmedal.net/files/houlden.htm
He was a mechanical engineer and "ballistics expert" who worked for CIL
I couldn't find a c. 1950s "OVAL" publication; likely Canadian?
He was close with “It is estimated that the tensile strength...would run 42,000-48,000 psi.” My study showed crolle averaged 54,700 psi
Burrard's 50X photomicrograph of etched (stained) crolle
20X nitrol etched specimen; iron white, steel dark
50X with silica, phosphorus, and sulfur ie. slag inclusions
What he did not notice is that the iron and steel components have migrated and are functionally a mono-metal, without the mythical internal oxidation/rusting. The superior crack is at the surface of the specimen, and is
within a steel alternee, not between the steel and iron.