Henri Schneider of France looks to be the cat responsible for the discovery/addition of nickel to steel probably in 1887/1888:
http://www.google.com/patents?id=hXptAAA...y_r&cad=0_0 . So any steel product such as a longarm tube from say the mid 1890s onward would be of the nickel-steel variety, of course with the possible exception of pattern welded tubes. I think he stumbled onto it due to the raw material/ore he was using had a nickel content.
I have a question regarding if a tube has the "Krupp Stahl" mark but not the area of "Essen" stamp, is it implied or since Krupp was a global steel powerhouse, could the tube been made via the Krupp process in another facilty outside of Germany? It sort of goes against the grain of Germany having Essen and the Suhl areas where all arms components could be sourced. But there are those tube stamps of a "T" or "K" inside a rotated square or rhombus usually seen with "Krupp Stahl" but sometimes or usually without the "Essen" stamp. Krupp looks to have an early interest in the Terni Steel Works hydro-electric facility in Italy in the first part of the last 1/4 of the 19th century, as did Vickers. From time to time terms like "Terni-Krupp" are seen. And the Germans and Italians were quite chummy. Or it could be a grade steel made by the Krupp process which includes a portion of the patent by Captain Tolmie John Tresidder,
http://www.google.com/patents?id=qdxCAAA...y_r&cad=0_0 . By the way Hayward A. Harvey of New Jersey looks to have advanced gun tubes and armour plates with a process akin to case colour harding where the steel is kept at a very high temp from a fortnight which draws the carbon toward the surface:
http://www.google.com/patents?id=3P1ZAAA...cad=0_0#PPA1,M1 Kind Regards,
Raimey
rse
