Thyssen Edelstahlwerke Ag

Thyssen Aktiengesellschaft Vorm. August Thyssen-hutte

Hans-Joachim Fleischer

Friedrich Behr

Helmut Brandis

Dieter Gorres

Heinrich Frinken

Hans-Heinrich Domalski

Kurt Bohnke

Klaus Lohscheidt

A ferritic, heat-resistant steel whose behavior at high application temperatures is improved by the combined addition of oxygen affinitive elements. Apart from stabilizing the electric resistance of heating elements by addition of zirconium, titanium and rare earth 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:

Semi-finished products of ferritic steel and catalytic substrate

The invention relates to a metallic semi-finished product based on iron and/or nickel and/or cobalt and containing 2 to 16% of aluminum, 12 to 30% of chromium and at least one highly reactive element X, in particular from the group consisting of the rare earth metals and/or their dispersed oxides. The characteristic feature of the invention is that metallic columnar crystals are formed at least in the surface region of the semi-finished product and columnar crystals consisting predominantly of aluminum oxide and/or chromium oxide grow out of the said metallic columnar crystals, the axes of the two types of columnar crystals being predominantly at right angles to the geometric surface of the semi-finished product.

Metallic semi-finished product, processes for its preparation and its use

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Velbert, Germany

Hans-Joachim Fleischer