Duplex & Super Duplex Steel Button Head Cap Screws

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
• Duplex button head cap screw features and benefits
• Datasheets for Super Duplex 2507 and Duplex 2205

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

Super Duplex 2507 screws 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 button head cap screws 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 screws 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

Duplex Screw Types: 12 Point Screws, Button Head Cap Screws, Flat Head Screws, Hex Cap Screws, Pan Head Screws, Set Screws, Socket Head Cap Screws, Tamper Resistant Security Screws, Torx Screws

Duplex Button Head Cap Screw Features & Benefits

Duplex button head cap screws combine the similar shape of a pan head with the driver of a socket head. The socket driver is ideal for low clearance applications that require a large area clamping face. Compared to a standard socket head cap screw, Duplex button heads have a lower and wider profile. This can be useful when the clamping material is too thin to counter-bore.

Advantages

• Wide bearing surface for clamping
• Low profile head

Duplex Screw 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 Gaskets / Super Duplex Gaskets

Engineered stainless gaskets: 2x stronger yield than 316 stainless steel

JG/JP Gasket

Parameters Temp: Cryogenic to 1830°F / 1000°C Pressure: Vacuum to 5800psi / 400bar Pressure class: 1500 / PN400 Carrier metal:  Stainless & Specialty alloys Thickness: 0.098" to 0.394" (2.5 - 10mm) Max dimension: 144in / 4000mm

Applications Extreme pressure & temperatures Corrosive media, H2, hazardous service Replaces: Spiral Wound / Kammprofile

Advantages Leak rate 15000x less than spiral wound Extreme pressure / vacuum sealing Highest temperature stability Corrosion & temp resistant alloys Customizable for dissimilar flanges & gaps Very low sealing force required Minimal graphite residue on change out Metal sealing protects PTFE / Graphite

• Decent general corrosion & cracking resistance
• Chemistry & Specs: Duplex 2205 & Super Duplex 2507
• Insight on Duplex 2205 & Super Duplex 2507 (1.4462, 1.4410)
• Strength Properties: tensile, yield & elongation charts
• Gasket availability & lead time
• Datasheet for Super Duplex 2507
• Datasheet for Duplex 2205

Duplex Gasket Overview

Duplex 2205 and Super Duplex 2507 (UNS S32205 / UNS S32750) stainless steel gaskets are characterized by their high yield strength, which is twice that of annealed austenitic stainless steels, like 304 and 316. In addition, Duplex steels offer improved corrosion protection compared to 300 series stainless, especially in terms of localized corrosion such as crevice and pitting, as well as stress corrosion cracking.  In general, Duplex steel gaskets are a great step up from 300 series stainless.

The main difference between the Duplex alloys is that 2507 offers higher strength and better corrosion resistance compared to Duplex 2205.
o  Duplex 2205: Higher strength and corrosion resistance than 300 series stainless.
o  Super Duplex 2507: Improved corrosion resistance and strength compared to 2205.

Duplex and Super Duplex semi-metalic gaskets with a PTFE or graphite soft sealing material are available in the Revoseal JG / JP design which is usable in the most corrosive environments and has a pressure rating of from vacuum to 5800psi / 400bar. WIth a leak rate 15000x less than spiral wound gaskets, you can be sure that hazardous fumes and vapors will be conatained creating the safest work environment possible. Furthermore, our Duplex 2205 and Super Duplex 2507 gaskets are customizable and accomodate dissimilar flange faces and large gaps.

Mechanical Properties
In general, Duplex gaskets have significantly better toughness and ductility than ferritic grades of steel, but not the levels of austenitic grades. Usage of both Duplex and Super Duplex stainless steel should be limited to temperatures below 570°F, as extended exposure to elevated temperatures can embrittle this material.

Key properties:
o  High strength and fatigue resistance
o  Good toughness & ductility
o  Temperature usage limit: 570°F
o  Low thermal expansion

Corrosion Resistance
Though Duplex steel gaskets are not ideal for harsh chemical environments, they do offer better corrosion resistance than 300 series stainless steel and are ideal for saltwater and chloride applications. Duplex bolts offer resistance to:
o  Saltwater: salt air, brackish water and marine environments.
o  Localized chloride corrosion: pitting and crevice corrosion as well as stress corrosion cracking.
o  Sulfide stress corrosion resistance
o  Oxidation

Which Duplex Steel is Best for Your Application?
The most common grades of Duplex steel gaskets are Duplex 2205 (1.4462) and Super Duplex 2507 (1.4410). If you are still not sure, our engineering team is here to offer their expertise on which grade will meet the specific requirements of your application.

Duplex Steel Gasket Availability

Custom Availability
Various Duplex grades and gasket designs can be made to order with standard lead time to be approximately 4 weeks. Be sure to contact us for specific lead times and any expediting needs.

• Duplex 2205 and Super Duplex 2507
• Max dimension: 144in / 4000mm
• Custom to print available
• NACE MR0175, ASTM, ASME, DFAR and Domestic available

Expediting Options
Let us know if you have lead time requirements that require a rush order so that we can accommodate them.

Common Duplex Grades

Duplex Alloy 2205 (1.4462)
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. Click here for more in-depth information on Duplex 2205.

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 (1.4410)
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. Click here for more in-depth information on Super Duplex 2507.

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

Mechanical Data

Duplex 2205 Fasteners / EN 1.4462

Duplex 2205 fasteners (EN 1.4462) are made from an austenitic-ferritic stainless steel, which was designed to deliver higher strength and corrosion resistance than 300 series stainless steels. It helps users to avoid stress corrosion cracking that is typically seen with 316 and 317. A Duplex screw combines the qualities of stress corrosion cracking resistance and high strength derived from being a ferritic alloy along with its austenitic fabrication capabilities.Download our datasheet for Duplex 2205.

Key Benefits of a Duplex Screw

• Good general corrosion resistance
• High resistance to chloride stress corrosion cracking, as well as pitting and crevice corrosion
• Good sulfide stress corrosion resistance
• High strength and good fatigue resistance
• Good weldability and workability
• High energy absorption
• Low thermal expansion

Duplex 2205 Strength
In comparison to SS316, Duplex 2205 has been tested under reverse bending stresses at room temperature. The results show that the fatigue limit/yield strength is about twice as high for Duplex 2205.

Duplex 2205 Temperature Capabilities
Duplex 2205 bolts have a a ductile to brittle transition at -50°C and can also become embrittled at temperatures of 300-1000°C, therefore recommended use is -50°C to 300°C. Exposure above 300°C will not only cause the embrittlement of a Duplex screw, but also reduced corrosion resistance.

Duplex 2205 Corrosion Resistance
Providing industry with an improved corrosion solution to stainless, Duplex 2205 fasteners offer good sulfide corrosion resistance, as well as chloride pitting and crevice corrosion resistant superior to 317L. The combination of chromium, molybdenum and nitrogen give Duplex 2205 fasteners good protection from chloride pitting and crevice corrosion, which makes it useful for marine environments, brackish water, bleaching operations, closed loop water systems and some food processing applications. Though it is important to keep in mind that pitting corrosion can be a concern in chloride solutions when oxidizing media is present. In these conditions, the passive (protective) layer of the Duplex 2205 material may be compromised in localized pitting may occur.

Physical Properties
Density: 7,860 kg/m3
Ultimate Tensile Strength: 110 ksi
Yield Strength: 80 ksi
Thermal Conductivity at room temperature: 8.7 (BTU/hrofto°F)
Electrical Resistivity at room temperature: 33.5 (in x 10-6)

Duplex 2205 Uses

• Chemical industries use Duplex 2205 fasteners and flanges on processing equipment, storage vessels and piping.
• Pulp and paper look to Duplex 2205 fasteners for use in digesters, bleaching equipment, stock-handling systems and liquid tanks.
• Marine as well as oil & gas extraction and processing uses 2205 fasteners in chloride and hydrogen sulfide environments

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

Duplex Fastener Types: Bolts, Nuts, Screws, Studs, Threaded Rods, Washers 

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

Duplex 2205 Grades / EN 1.4462, Chemistry & Specifications

Duplex 2205, UNS S32205, EN 1.4462, 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

Mechanical Data

Duplex 2205 Screws

Duplex 2205 screws are made from an austenitic-ferritic stainless steel, which was designed to deliver higher strength and corrosion resistance than 300 series stainless steels. It helps users to avoid stress corrosion cracking that is typically seen with 316 and 317. A Duplex screw combines the qualities of stress corrosion cracking resistance and high strength derived from being a ferritic alloy along with its austenitic fabrication capabilities. Download our datasheet for Duplex 2205.

Key Benefits

• Good general corrosion resistance
• High resistance to chloride stress corrosion cracking, as well as pitting and crevice corrosion
• Good sulfide stress corrosion resistance
• High strength and good fatigue resistance
• Good weldability and workability
• High energy absorption
• Low thermal expansion

Duplex 2205 Strength
In comparison to SS316, a Duplex screw has been tested under reverse bending stresses at room temperature. The results show that the fatigue limit/yield strength is about twice as high for Duplex 2205.

Duplex 2205 Temperature Capabilities
Duplex 2205 screws have a a ductile to brittle transition at -50°C and can also become embrittled at temperatures of 300-1000°C, therefore recommended use is -50°C to 300°C. Exposure above 300°C will not only cause the embrittlement of 2205 screws, but also reduced corrosion resistance.

Duplex 2205 Corrosion Resistance
Providing industry with an improved corrosion solution to stainless, Duplex 2205 screws offer good sulfide corrosion resistance, as well as chloride pitting and crevice corrosion resistant superior to 317L. The combination of chromium, molybdenum and nitrogen give a Duplex screw good protection from chloride pitting and crevice corrosion, which makes it useful for marine environments, brackish water, bleaching operations, closed loop water systems and some food processing applications. Though it is important to keep in mind that pitting corrosion can be a concern in chloride solutions when oxidizing media is present. In these conditions, the passive (protective) layer of the Duplex 2205 material may be compromised in localized pitting may occur.

Physical Properties
Density: 7,860 kg/m3
Ultimate Tensile Strength: 110 ksi
Yield Strength: 80 ksi
Thermal Conductivity at room temperature: 8.7 (BTU/hrofto°F)
Electrical Resistivity at room temperature: 33.5 (in x 10-6)

Duplex 2205 Uses

• Chemical industries use Duplex 2205 screws on processing equipment, storage vessels and piping.
• Pulp and paper look to Duplex 2205 screws for use in digesters, bleaching equipment, stock-handling systems and liquid tanks.
• Marine as well as oil & gas extraction and processing uses 2205 screws in chloride and hydrogen sulfide environments

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

Duplex Fastener Types: Bolts, Nuts, Screws, Studs, Threaded Rods, Washers 

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

Duplex 2205 Grades, Chemistry & Specifications

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

Mechanical Data