- the Henrichshütte in Hattingen (until 1930 to Henschel & Sohn , Kassel)
- the Oberkassel and Gelsenkirchen plants of the Rheinisch-Westfälische Stahl- und Walzwerke AG from Gelsenkirchen,
- the Annen cast steelworks in Witten-Annen ,
- the cast steel plant in Witten and
- the Brackwede plant of the Vereinigte Press- u. Hammerwerke Dahlhausen-Bielefeld AG .
During the Second World War they were arms manufacturers . That is why they were shut down from 1945, but were later allowed to repair railways and manufacture pumps and the Ruhrstahl implement carrier (tractor-like device). This tractor was only produced until the production restrictions on armaments were lifted again. At the end of the 1950s, the Ruhrstahl-Heraeus process was developed in Henrichshütte , which is still used today for vacuum degassing of steel under this name.
In 1957 Ruhrstahl became part of the Rheinstahl group, which in turn was taken over by Thyssen in 1973.
The Witten and Krefeld plants that still exist today are part of Deutsche Edelstahlwerke Specialty Steel .
- Werner Bührer: Ruhrstahl and Europe. The Iron and Steel Industry Association and the Beginnings of European Integration 1945–1952 (= series of quarterly journals for contemporary history . Volume 53). Oldenbourg, Munich 1986.
- Early documents and newspaper articles on Ruhrstahl in the 20th century press kit of the ZBW - Leibniz Information Center for Economics .