AG in German Corporations Law is “Aktien Gesellshaft” ( a Company organised by Shares(Stock to you Americans).
Which means a “public” Corporation ( the shareholders can be numerous and from the general public. Of Course, the Krupp Family had the controlling Interest in the Company.
The corresponding term in French is "SA “( Societe Anonyme–” anonymous society, ie the names of the owners are on the Register of Stockholders, but not publicly known); in Italy, it is "SpA: Societa per Azioni…company for Shares; in the Slavic languages it is “AS” ( Akcioni Spolecnost in Czech);
in Swedish it is “AB” (Aktien Bolaget) and in British terminology it is “Ltd” (Limited).
The other “form” of company/corporation which is "Privately "owned, but by shares (ie, NOT a partnership or co-operative or sole trader) is the “GmbH” in German (don’t ask me to explain the detail), “SRL” in Italian ( “limited responsibility society) and " Pty.Ltd or Pvt.Ltd” in British/ Australian law.
The Krupp industries got their start in the Railroad supplies Industry: Rails, Fishplates(Joiners) Dogspikes, “Tyres” ( the forged steel rim which was “shrunk” onto the central, cast iron wheel) Axels and by the 1880s, Complete Locomotives.
By 1851, they had perfected casting Steel in a big way, and also began forging solid Steel Gunbarrels for Light field pieces, then large filed pieces, naval Guns and even rifle barrels.
Krupp also perfected the “Trepanning” system of Boring a cannon barrel, using a hollow drill,( concept the same as a “Hole” drill") which left a solid central bar of steel, and cut down on the Boring time for medium diameter and large diameter Canno tubes.
“Hutte” in German techspeak, is a “Steel Works” or “Iron Works”; it comprises the Blast furnace for the conversion of Iron ore into Raw iron, and the subsequent conversion of this into Raw Steel, with the accessory Rolling Mills to convert the Ingots into “Blooms” and then Plates, bars, and rails.
Krupp rails opened up most of the South American continent, a Large part of Australia and Africa, as well as Most of Europe, Russia and some parts of the USA, especially during the great railroad expansion in the 1860s-70s.
I regularly see Krupp marked 42 Pound rail on some of the older routes of the Queensland Railways, even if only as fence-posts and Cattle gratings.
Regards, Doc AV
AV ballistics ( and a Railway Historian/railfan/modellist as well)