I have not been able to find a U.S. registered trademark for "Titanic Steel"; by a mill or by Parker Bros.
Interestingly there was a Vulcan Crucible Steel Co. in Aliquippa, PA and a Vulcan Charcoal Iron & Steel in Crum Lynne, PA.
Steel Importers 1905
The Iron Age Directory, David Williams Co., 1911
http://books.google.com/books?id=cht...J&pg=PA390&lpg
Listed the following companies under
“Steel, Gun Barrel”
Edgar Allen & Co. Chicago, Ill.
Bethlehem Steel Co., South Bethlehem, Pa.
Carnegie Steel Co., Pittsburgh, Pa.
Colonial Steel Co., Pittsburgh, Pa.
Crucible Steel Co. of America, Pittsburgh, Pa
Farist Steel Co., Bridgeport, Ct
Wm. Jessop & Sons, Inc, 91 John St. New York
C. Pardee Works, Perth Amboy, NJ
Thomas Prosser & Son, 26 Platt St. NY
Vanadium Alloys Steel Co., Latrobe, Pa
West Leechburg Steel Co., Pittsburgh, Pa