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

Duplex Hex Bolts

Duplex 2205 and Super Duplex 2507 stainless steel hex head bolts 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 bolts. Because of this, Duplex 2205 and Super Duplex 2507 steel are some of the most common grades of duplex used for bolts with Super Duplex 2507 bolts being the more corrosion resistant grade of the two.

Super Duplex 2507 hex head bolts 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 hex head bolts 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 bolts 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.

ResourcesDuplex & Super Duplex Torque Specs

Duplex Bolt Types: Hex Head BoltShoulder Bolt


Duplex and Super Duplex Hex Head Bolt Features and Benefits

It is important to differentiate between a Duplex hex head bolt and hex head cap screw. Often people assume they are the same, but they are actually very different fasteners in terms of how they are manufactured, as well as from an application perspective. Regardless of your choice, Duplex and Super Duplex hex heads offer strong, stable joints because of their large head service. 

The Hex Comparison

Hex Head Bolts

Hex Head Cap Screw
  • Hex bolts have a flat end and lack the washer face under the head.
  • Appropriate for when mechanical properties are more important than dimensional tolerances.
  • Features flat washer facing under the bolt head.
  • Also called a finished hex bolt. 
  • Has tighter tolerances on the body dimensions. 
  • Best used for precise applications where tight tolerances on the body dimensions are required. 

 


Duplex Bolt 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 Alloy 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

Duplex 2205 Chemistry

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

Super Duplex 2507

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

Zeron 100 Chemistry

 


Mechanical Data

Duplex Stainless Tensile Data

 

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