Effects of Cr, Al and Ti Contents on Resistance to Abnormal Oxidation Formability and Weldability of Cr-Al Steels for Automobile Emission, Control Devices

Abstract

The development of Cr-Al steels for automobile emission control devices has been really desired from both the standpoint of low cost and economy of nickel resource. Cr-Al steels, however, are poor in formability and weldability, and moreover they sometimes suffer from such abnormal oxidation that oxidation proceeds locally in oxidizing atmospheres. Especially, the abnormal oxidation proceeds in a more accelerated from in exhaust gas than in air.
In this study, the effects of alloying elements, Cr, Al and Ti, on the resistance to abnormal oxidation, formability and also weldability of Cr-Al steels were investigated.
Consequently the addition of 0.3% titanium to Fe-22% Cr-2.4% Al-base alloy containing low C and low N was found to improve the resistance to abnormal oxidation in exhaust gas, formability and weldability.