SEMI-FINISHED PRODUCTS OF FERRITIC STEEL

摘要

The invention relates to a ferritic, heat-resistant steel whose behaviour at high application temperatures is improved by the combined addition of oxygen affine elements. Apart from stabilizing the electric resistance of heating elements by addition of zirconium, titanium and rare metal, also the creep elongation of the steel is considerably reduced under load at temperatures above 900.degree.C, the thermal stress capacity thus being increased. The resulting complex oxide coating increases the protective function with regard to preserving the metallic cross-section in continuous and/or cyclic heat treatments. The steel is composed of: max. 0.10 % C max. 0.80 % Si 0.10 to 0.50 % Mn max. 0.035 % P max. 0.020 % S 12 to 30 % Cr 0.10 to 1.0 % Mo max. 1 % Ni 3.5 to 8 % A1 0.01 to 1 % Zr 0.003 to 0.8 % rare metals 0.003 to 0.30 % Ti 0.003 to 0.050 % N remainder Fe and incidental impurities.