Terry A. DeBold

Duplex stainless steel—Microstructure and properties

Literature describing the microstructure of austenitic-ferritic stainless steels is reviewed, including phases which can be deleterious, such as σ and ά. The mechanical properties and corrosion resistance of Carpenter Technology’s 7-Mo PLUSsr stainless (UNS S32950) demonstrate the resistance of this material to the formation of these phases and their deleterious effects. This material was evaluated in the annealed and welded conditions and after extended thermal treatments to simulate boiler and pressure vessel service.

Custom age 625® plus alloy—A higher strength alternative to alloy 625

Highly corrosion- resistant, age- hardenable alloys are needed in severely corrosive environments such as those encountered in deep sour- gas wells. Age hardenability is important because high strength levels of 827 MPa (120 ksi) minimum 0.2% yield strength are required in large section sizes. Custom Age 625 PLUS was developed to provide higher strength levels than those attainable with alloy 625 along with similar corrosion resistance (more corrosion resistant than alloy 718). The development and metallurgy of Custom Age 625 PLUS are reviewed. The mechanical properties and corrosion resistance of 625 PLUS, 625, and 718 alloys are compared.

Corrosion resistance and mechanical properties of a new duplex stainless

Corrosion resistance and mechanical property data are presented for a new duplex stainless steel. The study includes resistance to several forms of corrosion, including intergranular corrosion and pitting attack as well as resistance in highly oxidizing environments. Mechanical property data at room and elevated temperatures are discussed.