Weldable and corrosion-resistant ferritic stainless steels

High-chromium ferritic stainless steels have been little used as materials of construction because they lose their corrosion resistance and ductility when welded. Good as-welded properties depend on controlling interstitial carbon and nitrogen. Three methods of achieving such control are described: 1) reducing the interstitials to critical low levels; 2) including weld ductilizing additives, which “soften” the matrix; 3) using additives to complex the interstitials. The third method is particularly useful, since it eases the requirements for raw-material purity and melting techniques to control carbon and nitrogen. This paper is based on a presentation made at a symposium on “New Developments in Ferritic and Duplex Stainless Steels,” held at the Fall Meeting in Cleveland, Ohio, on October 19, 1972, under the sponorship of the Corrosion Resistant Metals Committee of TMS-IMD and the Corrosion and Oxidation Activity of the ASM.