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Duplex Grades

Duplex stainless steels are extremely corrosion resistant, work hardenable alloys. Duplex stainless steel plate contains relatively high levels of chromium (between 18% and 28%) and low to moderate amounts of nickel (between 1.5% and 8%). The high corrosion resistance and excellent mechanical properties of duplex stainless steels can be attributed to their chemical composition and balanced (duplex) microstructure of approximately equal volume percentages of ferrite and austenite. Because of this duplex nature, it will display properties characteristic of both austenitic and ferritic stainless steels. Duplex stainless steels are in most cases, tougher than ferritic stainless steels. Strengths of duplex stainless steels can in some cases be double that for austenitic stainless steels.

Introduction to Duplex Stainless Steel PDF



Penn Stainless stocks the following products in Duplex Grade stainless steel:

Stainless Steel Duplex Products
Stainless Steel Plate Plate Mill Plate, Diamond Plate More Information
Stainless Steel Sheet 2B/2D Finish, Polished Sheet, Perforated Sheet, Flat & Expanded More Information
Stainless Steel Bar Round Bar, Square Bar, Hex Bar, Rolled Flat. Sheared&Edged, Half Round More Information
Stainless Steel Structural Angles, Unequal Leg, Channel, Beams, Ornamental Square Tube, Ornamental Round Tube, Ornamental Rectangular Tube More Information
Stainless Steel Tubular Seamless Pipe, Welded Pipe, Seamless Tube, Seamless Tube More Information


Common Applications
Due to their high strength and corrosion resistance properties, Duplex Stainless Steels are used in a variety of applications such as:
• Pressure vessels, reactor tanks and heat exchangers
• Desalination plants and seawater systems
• Water transmission pipes
• Rotors, impellers and shafts in industrial equipment
•Stock washers and other equipment for the pulp and paper industry
• Absorber towers, FGD systems for air pollution control
• Phosphoric acid production
• Food, oil and gas, mining and architectural applications
• Biofuels plants
Duplex Stainless Steels combine many of the beneficial properties of ferritic and austenitic materials to provide both high strength and good corrosion resistance. Due to their high chromium, molybdenum and nitrogen contents and duplex structure, these steels offer many benefits in comparison to 300 series austenitic grades:
• High Strength – Approximately twice the level of austenitics
• Good resistance to pitting and crevice corrosion
• Excellent resistance to stress- corrosion cracking
• Good erosion and fatigue resistance
• Good weldability and increased heat transfer
• More stable pricing due to lower Ni levels than austenitic stainless grades


Duplex 2205Penn Stainless inventory now includes Duplex 2205 (UNS S32205 / S31803), in sheet, sheet coil, plate, plate coil, round bar, processed flat bar and tubular products. Duplex 2205 is ideally suited for high-pressure and highly corrosive environments.More Information
Duplex 2304 Penn Stainless inventory now includes Duplex 2304 (UNS S32304) in sheet, sheet coil, plate, round bar, processed flat bar and tubular products.More Information
Duplex 2507Penn Stainless inventory now includes Duplex 2507, which is a super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel.More Information
LDX2101Penn Stainless inventory now includes Alloy LDX2101 (UNS S32101) in plate and flat bar products.More Information