Super Duplex 2507 Fasteners belong to the super duplex grade of steels. They have the qualities of ferritic and austenitic steel grades. There are three different types of duplex steels as standard duplex, super duplex and lean duplex. The super duplex is used most next to the standard duplex. The Super Duplex 2507 Bolts are costlier than the standard duplex and other grades of steel types because of their composition. The material has 25% chromium, 4% molybdenum and 7% nickel in the content.

The Super Duplex Stainless Steel Bolts and Nuts have very high corrosion resistance, especially the chloride ion corrosion cracking resistance. They are also resistant to pitting and crevice attack. Due to these qualities, the Super Duplex 2507 Hex Bolts are suitable for marine, sea water, brackish water applications such as water desalination plants. Other applications include flue gas scrubbing equipment, pulp and paper industrial applications, offshore oil drilling and production.

Specifications of Duplex Fastners


ASTM / ASME F53, A479 / SA479


ASTM / ASME F53, A479 / SA479


3 mm to 200 mm

Nuts Size

M3 – M56 | 3/6″ to 2″ | Custom Sizes

ASTM A182 F53 UNS S32750 Bolts / Screw Size

M3 – M56 | 3/6″ to 2″ | Custom Sizes


DIN, UNI, ISO, JIS, GB, IS, BS, ASME, ANSI, ASTM and all International Standards

Bolts, Studs Threads

METRIC, BSW, BSF, UNC, UNF or as required

In Form of

Hex, Square, Round, Threading as per Gauge Etc.

Head drive

Phillips, Slotted, Phillips/Slot, Six-Lobe, etc

Bolts Size

M2, M2.5, M3, M4, M5, M6, M8, M10, M12, M14, M16, M20, M24, M30, M36 to M160

Machine Screws Size

M1.6 – M12

Washers Size

M3 – M56 | 3/6″ to 2″ | Custom Sizes

Test Certificate

Manufacturer Test Certificate as per EN 10204 / 3.1

Source of raw materials

Tata Steel, JSPL, RINL, Usha Martin, Dhamm Steel, Mukund Steel etc.

Scope Of Manufacture

Hot Forged , Nut / Bolt; up to M36 / 1-1/2” Dia, up to 1100mm lg
CNC Machined , Nut / Bolt; up to M100 / 4” Dia, up to 1500mm lg

Super Duplex Steel Grades

Super Duplex Steel UNS S32750


IN BULK: canton, pallet, Small Boxs / carton / pallet, or customer request

Production process

M2-M24: Cold Froging, hot forging M24-M100, machining and CNC for Customized connecting element

Super Duplex 2507 Fasteners Standard

ANSI – American National Standards Institute  

ANSI B 18.2.4 2M
ANSI B 28.2.4 1M
SS 304l Stud Bolt length are defined in ASME B16.5 standard
SS 304l Hex nuts are defined in ASME B18.2.2
ASME B18.5
DIN: DIN 931, DIN 933, DIN 934, DIN 970

UTS – Unified Thread Standard : UNC, UNF, UNEF, UNS, NPT, NPTF

ISO – International Organization for Standardization : ISO 4032, ISO 4033, JIS standards

Alloy 2507 Fasteners Type

Hex Coupling Nut, Hex Nut, Square Nut, Hex Domed Cap Nuts, Hex Head Bolts, Stud Bolts, Socket Hexagon Head Screw, Pan Head Screw, Socket Head Cap Screw, Wing Screw, T-Head Bolts, Foundation Bolts,Screw, Studs, Socket Screw, Hex Set Screw, Cap Screw, Machine Screw, Wing Screw, Spring Washers, Washers, Studs, Marine Anchors, Anchors, Hexagon Nut,U- Bolts, Anchor Bolt, Mushroom Head Square Neck Bolts, J Bolts,Eye Bolt,Structural Bolts, Bolts, Nuts, Sockets, Screws, Allen Cap screw,Nut

Chemical Composition of Duplex Fastners













0.030 max

2.00 max

1.00 max

0.030 max 

0.020 max

22.0 – 23.0

3.0 – 3.5

4.50 – 6.50

0.14 – 0.20

63.72 min


0.030 max

2.00 max

1.00 max

0.030 max

0.020 max

21.0 – 23.0

2.50 - 3.50

4.50 – 6.50

0.8 – 0.20

63.54 min

Chemical Compatibility Of SAF 2507 Fasteners


Content (%)

Chromium, Cr

24 – 26

Nickel, Ni

6 – 8

Molybdenum, Mo

3 – 5

Manganese, Mn

1.20 max

Silicon, Si

0.80 max

Copper, Cu

0.50 max

Nitrogen, N

0.24 – 0.32

Phosphorous, P

0.035 max

Carbon, C

0.030 max

Sulfur, S

0.020 max

Iron, Fe


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