An engineered stainless steel known for its high yield strength & decent corrosion resistance

• High Strength - About 2x stronger yield than 316 stainless steel
• Super Duplex - Decent general corrosion & cracking resistance
• Duplex Grades: Duplex 2205, Super Duplex 2507, Zeron 100
• Threaded flange features and benefits
• Datasheet for Super Duplex 2507
• Datasheet for Duplex 2205

Duplex 2205 and Super Duplex 2507 stainless steel threaded flanges are characterized by their high yield strength, which is twice that of the annealed yield strength of typical austenitic stainless steels, like 304 and 316 stainless steel threaded flanges. Because of this, Duplex 2205 and Super Duplex 2507 steel are some of the most common grades of duplex used for threaded flanges with Super Duplex 2507 threaded flanges being the more corrosion resistant grade of the two.

Super Duplex 2507 threaded flanges improved corrosion resistance lends itself well too applications prone to stress-corrosion cracking, crevice corrosion, pitting, erosion and general corrosion. Because of the properties of Duplex and Super Duplex stainless steel threaded flanges are often used in chemical processing, petrochemicals, power industry and seawater equipment.

Usage of both Duplex and Super Duplex stainless steel should be limited to temperatures below 570° F as extended elevated temperature exposure can embrittle this material.

The most common grades of Duplex flanges are Duplex 2205 and Super Duplex 2507. Gain more insight on these two grades by accessing our Duplex 2205 and Super Duplex 2507 overviews or by contacting our engineering experts.

Resources: Duplex & Super Duplex Torque Specs, Flange Dimensions, Flange Bolting Chart

Flange Types Available: Blind Flanges, Lap Joint Flanges, Slip On Flanges, Socket Weld Flanges, Threaded Flanges, Weld Neck Flanges 

Duplex Threaded Flange Grades, Chemistry & Specifications

Duplex Alloy 2205 

Duplex 2205, UNS S32205, is a stainless steel material, whose “Duplex” name is derived from the mixed microstructure which contains roughly equal portions of ferrite and austenite. This grade is the most popular variety and this two-phase material is a significant upgrade from 316 stainless steel in terms of both yield strength and corrosion resistance. 

Duplex 2205 Specifications: ASME SA 182, ASME SA 240, ASME SA 479, ASME SA 789, ASME SA 789 Section IV Code Case 2603, ASTM A 240, ASTM A 276 Condition A, ASTM A 276 Condition S, ASTM A 479, ASTM A 790, NACE MR0175/ISO 15156, NORSOK MDS D45 Grade F51, UNS S31803, UNS S32205, W. NR./EN 1.4462, Werkstoff 1.4462 Duplex

Super Duplex Alloy 2507 

Super Duplex 2507, UNS S32750, is a two-phase stainless steel and is particularly well suited for use in environments such as warm chlorinated seawater and acidic, chloride containing media. It has similiar properties to Duplex 2205 but is more corrosion resistant and performs well in moderately corrosive environments. 

Super Duplex 2507 Specifications:  EN 10216-5, ASTM A789; A790, ASTM A182 ASTM A182, ASTM A815, ASTM A240, EN 10088-2, ASTM A479, EN 10088-3 EN 10088, ISO 15156-3, NACE MR0175, Werkstoff 1.4410 S.Duplex

Zeron 100 / F55:

Zeron 100, UNS 32760, is commonly know as F55, which is a slight varient of Super Duplex 2507. This alloy is well suited or seawater applications.

Zeron 100/F55 Specifications: ASTM A 182, ASTM A 182 (Grade F55), ASTM A 240, ASTM A 276, ASTM A 473, ASTM A 479, ASTM A 790, ASTM A 815, ASTM A314, NORSOK MDS 055, UNS S32760, W. Nr./EN 1.4501, Werkstoff 1.4501

Mechanical Data

Duplex & Super Duplex Threaded Flange Features & Benefits

Duplex and super duplex threaded flanges have a tapered female thread to join the male threads of a pipe in order to create a tight seal. This type of flange is most ideal when post weld heat treatment is not possible in hazardous, flammable or explosive applications where welding is too dangerous. Duplex and super duplex threaded flanges are also convenient in pilot processes whose configuration is often changed.

Threaded Flange Advangtages

• The main benefit is that that threaded seal eliminates the need for welding.
• As they do not require welding they save time and money to install.
• Allow for connections to be made in dangerous, explosive applications where welding is not possible.
• Useful connection in materials that are difficult to create a successful and strong weld.
• Ideal for connecting small diameter pipes.
• Systems could be easily reconfigured.

Threaded Flange Disadvantages

• They are not suitable where high temperatures, frequent cyclic conditions or bending stresses are likely in applications.