The Effect of Carbon, Zirconium, Niobium, and Titanium on the Oxidation Resistance of Chromium Stainless Steel

Abstract

The effects of C, Zr, Ti, and Nb on the oxidation resistance of 17 % Cr steels have been investigated by means of isothermal heating and cyclic heat-ing at temperatures up to 1000 ~ It has been found that C has a det r imenta l ef fect on the oxidat ion resistance of 17 % Cr steels. The oxidation behavior of steels containing Zr is different from that of steels containing Ti and Nb. Zr improves the oxidation resistance of 17 % Cr steels to a great extent. Par-t icularly, alloys containing Zr at a concentration which exceeds the stoichio-metr ic equivalent of the total amount of C and N show excel lent oxidation resistance up to 1000 ~ Electron probe microanalysis shows the presence of a protect ive oxide layer consisting of Si-r ich oxide at the metal-oxide inter-face, and no Zr is detected in the scales. With steels containing Ti and Nb, on the other hand, there is no protective Si-r ich oxide, but Ti and Nb are detected in the scales. These scales are not protective. As the effective factors of excel lent oxidation resistance of Cr steels containing Zr, the behavior of