Just for clarity "flussstahl" was a generic term that had been in use in Germany at least since the 1870s.
Metallurgy of Steel, Henry Marion Howe, 1916
http://books.google.com/books?id=KX8MAAAAYAAJ&vq
The 1876 Philadelphian Nomenclature uses the terms ingot steel (French: acier fondu, German: flussstahl) for medium or high carbon molten origin steel with a tensile strength greater than 71,000 psi.
“Mild” or low carbon steel with a tensile strength less than 71,000 psi was referred to as ingot iron, fer fondu, and flusseisen. The dividing tensile strength for structural steels in the U.S. was later set at 65,000 psi.

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