New Ferritic Stainless Steels for Automotive Trim Application 830586
New ferritic stainless steels have been developed for use by the automobile industry. These steels demonstrate high resistance to pitting and a longer product lifetime can be expected, especially in "chloride type" environments. This report deals with the effects of alloying elements on steels containing 16-19% Cr, with special attention devoted to pitting resistance.
It was observed that a small amount of Cu and Ni increased pitting resistanc. A decrease in the S content of the steel led to an increase in the pitting resistance. The remarkable improvement in the rust staining resistance for this low S steel was confirmed by the CASS test. Based on results, 19%Cr–0.5%Cu–Ni– (Nb)–low S ferritic stainless steels were selected. These steels "NSS442M2" and "NSS442M3" have excellent rust staining resistance in the accelerated tests. The atmospheric exposure test proved that the rust staining resistance of NSS442M2 and NSS442M3 was comparable to or greater than that of Type 304.