Sunday, 25 April 2010
Use of duplex and super duplex increases
During the last twenty years there has been a large increase in the use of duplex and super duplex stainless steels. These are the "second generation" of duplex stainless steels. These grades are distinguished from the first generation by their ability to retain a good balance of austenite and ferrite, and thereby toughness and corrosion resistance, in the welded condition. This improvement results from the use of nitrogen as an intentional and precisely controlled alloying addition. Second generation duplex stainless steels have enjoyed wide acceptance because they offer excellent combinations of strength, pitting and crevice corrosion resistance as well as chloride stress corrosion cracking resistance, for a very economical cost. As fabrication experience with these duplex alloys increases, it has become recognized that these technically complex duplex grades require increased qualification and care in production and fabrication to assure safe and economical results.