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Normalized high-strength Mn-Mo-V-Cb steels have been developed for a broad range of structural applications, including pressure vessels which serve at elevated temperatures lower than the creep range. The high yield strength is particularly suitable for designs based on the ISO Pressure Vessel Code Draft which is to be accepted by European countries and possibly by Japan. In the chemical composition range of 0.08/0.13 % C, 1.5/1.9 % Mn, 0.25/0.45 % Mo, 0.06/0.10 % V, and 0.02/0.05 % Cb, normalized-and-aged plates up to 70 mm in thickness can exhibit yield strengths of 450 MPa at room temperature and 300 MPa at 350 Cel. The Charpy V-notch impact energy of the plates with 450 MPa, may exceed 67 J at -45 Cel. Molybdenum imparts thermal stability, hardenability, and resistance of the steel to temper softening. Effects of other alloying elements, including titanium and boron, were also investigated. Weldability of the test steels is demonstrated by the maximum HAZ hardness test and the y-groove cracking test. (Wassmann)