Duplex stainless steels are finding increasing use in the pulp and paper industry because they offer a highly economical combination of strength and corrosion resistance. Duplex stainless steels have existed for well over sixty years. However, the first generation of duplex stainless steels was not readily welded without loss of toughness and corrosion resistance. Consequently, their practical use in process applications such as those regularly encountered in a pulp and paper mill was severely limited. In the last decade a second generation of duplex stainless steels has come into commercial production. These grades are characterized by a composition balance, particularly the use of relatively high contents of nitrogen as an alloying element, that allows practical welding without loss of desirable properties.
This document is intended to assist in identification of duplex stainless steels appropriate to application in this industry and to offer general guidelines for the qualification of welding procedures and for the installation of duplex stainless steels, assuming that the reader has a basic familiarity and experience with fabrication and welding of austenitic stainless steels, most typically Type 316L.
