Stainless Steel Workshop: Weldability of ferritic stainless steels

Q: What filler wires are best-suited for welding ferritic stainless steel?

A: Automotive exhaust systemand component manufacturers such as ArvinMeritor, Benteler, Faurecia, and Delphi have welded ferritic stainless steel for years. Their choice of filler metal, either a 409 or a 439, provided a corrosion-resistant deposit as well as a degree of oxidation resistance.

Although solid wire had the necessary properties to weld ferritic materials, the North American market quickly chose tubular wire. Tubular wire, or metal-cored wire as it is more commonly known, contains metallic powders along with alloys such as chromium, titanium, or niobium. Metallurgically, these wires can produce the designed properties to match the properties of the ferritic steels.

Ferritic metal-cored wires can provide the high deposition efficiency needed, along with an ability to bridge joints where fit-up is poor. In addition, the wire’s ability to weld at faster travel speeds than conventional solid wires may increase productivity by as much as 40 percent.

Ferritic metal-cored wires come in a variety of compositions from 11 percent to 19 percent chromium and can be easily customized for specific metallurgies.