Duplex stainless steels contain a mixture of austenite and ferrite in their structure, and exhibit characteristics of both phases with higher strength and ductility. Nitrogen is added to the second generation duplex alloys and provides strength and improved weldability. NITRONIC® 19D is an example of a duplex stainless steel grade with good cyclic oxidation, high strength, and good stress corrosion cracking resistance. Type 2205 duplex stainless steel is a grade that offers very good pitting and uniform corrosion resistance, high strength and high resistance to stress corrosion cracking. Typical applications for duplex alloys are heat exchangers, tubes, pipes, pressure vessels and tanks in the oil and gas and chemical processing industries.