Duplex stainless steel earns its name from it two-phase microstructure consisting of near equal parts of ferritic and austenitic stainless steel. Invented nearly 80 years ago, duplex stainless steel has been exploited by engineers ever since for its corrosion and cracking resistance, as well as its strength, cost and its weight advantages.
According to the International Molybdenym Association, duplex stainless steel offers the following array of qualities:
Strength – Duplex stainless steel is nearly twice as strong as ferritic stainless steel and austenitic stainless steel.
Toughness & Ductility – Duplex stainless steels have significantly better toughness and ductility than ferritic grades.
Corrosion Resistance – As with all stainless steels, corrosion resistance depends mostly on the composition of the stainless steel. For chloride pitting and crevice corrosion resistance, their chromium, molybdenum and nitrogen content are most important. Duplex stainless steel grades have a range of corrosion resistance, similar to the range for austenitic stainless steels, i.e from Type 304 or 316 (e.g. LDX 2101©) to 6% molybdenum (e.g. SAF 2507©) stainless steels.
Stress Corrosion Cracking Resistance – Duplex stainless steels show very good stress corrosion cracking resistance – a property inherited from their ferritic side.
Cost, Weight and Workability – Duplex stainless steels have lower nickel and molybdenum contents than their austentic counterparts, while offering similar corrosion resistance. Due to the lower alloying content duplex stainless steel can be lower in cost, and it may be possible to reduce the section thickness, which can lead to significant cost and weight savings when compared with a solution in austenitic stainless steel.
Duplex stainless steel is used in a variety of industries such as oil and gas, chemical processing, power generation, desalinization, and forestry/pulp and paper, prized for its toughness and its corrosion and cracking resistant qualities.
Steelcraft’s Engineered Products Division has been producing products created from duplex stainless steel since 1991, and our team has built up significant expertise in welding and in managing this sophisticated alloy, as our customers turn to duplex stainless products over 300 series stainless products. Steelcraft products produced in duplex stainless steel include heat exchangers, pressure vessels, and most recently liquid storage tanks – a product that of late has been rising in popularity in the oil and gas sector. For more information about our duplex stainless steel manufacturing capabilities, contact us at firstname.lastname@example.org.