What material grade does S32520 Super Duplex Fasteners use?

S32520 Super Duplex Fasteners are manufactured per the applicable ASTM, ASME, DIN, or ISO specification for the material grade. TorqBolt provides material test certificates (MTC) per EN 10204 3.1 or 3.2 with every supply.

What sizes are available for S32520 Super Duplex Fasteners?

TorqBolt manufactures S32520 Super Duplex Fasteners in metric sizes M6 to M100 and imperial sizes 1/4" to 4" diameter, with custom lengths from 10mm to 3000mm. Non-standard sizes are available on request.

Are S32520 Super Duplex Fasteners NACE MR0175 / ISO 15156 certified?

Yes, S32520 Super Duplex Fasteners can be supplied with NACE MR0175 / ISO 15156-2/3 sour service certification when specified at order. Material certificates and test reports are provided.

What is the typical delivery time for S32520 Super Duplex Fasteners?

Standard stock items ship in 1-2 weeks. Custom manufactured S32520 Super Duplex Fasteners typically ship in 4-6 weeks depending on quantity, material availability, and certification requirements.

Do you provide third-party inspection for S32520 Super Duplex Fasteners?

Yes, third-party inspection by TUV, Lloyd's Register, BV, DNV, SGS, and Intertek is available upon request for S32520 Super Duplex Fasteners. Witness testing and stage inspections can be arranged.

S32520 Super Duplex Fasteners Supplier

S32520 Super Duplex Fasteners Specification

S32520 Super Duplex Fasteners Heavy Hex Bolts Screws Studs Nuts Washers

S32520 is also known as UNS S32520 or Bs En 1.4507. It is a high chromium nickel super duplex stainless steel. It has very good resistance against corrosion and pitting against corrosives such as sulphuric acid. It is advisable not to use this type of steel in high temperature applications where tensile strength of a material is 770 Mpa and yield strength is 550 MPa. They are used in oil refining, fertilizer, papermaking, petroleum, high temperature heat exchangers. etc.

S32520 Super Duplex Fasteners Properties

Equivalent Designation
ASTM/ASME	AISI	UNS	British Standard	Werkstoff No.	En Name	Swedish(SS)	JIS(SUS)
Sa 182 F61	–	S32520	–	1.4507	X2CrNiMoCuN25-6-3	–	–

TorqBolt manufactures S32520 Super Duplex Fasteners via cold forging, hot forging and CNC machining. Sizes range from M1.0 to M100 (metric) and 1/16" to 4" (imperial). Available in coarse, fine, UNC, UNF, UN, BSW and acme threads with half, full or double-end thread configurations. Each S32520 Super Duplex Fasteners batch is supplied with EN 10204 3.1 or 3.2 material test certificates.

Hexagon Bolts

ANSI B18.2.1
ANSI B18.2.3.1M
DIN 931
DIN 933
BS 1768
UNI 5731
UNI 5737
UNI 5739
ISO 4014
ISO 4017
BS 1769
BS 3692

Socket/Slotted Set Screws

DIN 913
DIN 914
DIN 915
DIN 916
DIN 551
DIN 553
DIN 438
BS 4168

Socket/Slotted Countersunk Screws

DIN 963
DIN 7991
BS 4168
BS 1981
BS 483
BS 2470

Socket Cap Screws

ANSI B18.3
B18.3.1M
DIN 912
DIN 6912
DIN 7984
ANSI B18.3
ISO 4762
UNI 5931
BS 2470
BS 4168

Stud Bolts

ASME B18.2.1
DIN 976
DIN 938
DIN 939
DIN 2510
BS 4439
BS 2693
BS4882

Nuts

ANSI B18.2.2
ANSI B18.2.4.6M
DIN 934
DIN 936
BS 1768
BS 1769
BS 1083
BS 3692
ISO 4032
ISO 4033
ISO 4035
UNI 5587
UNI 5588
UNI 5589

Washers

ASME B18.22.1
ASTM F436
ISO 7089
DIN 125
DIN 9021
BS 4320
BS 3410
DIN 127
BS 4464
BS 1802
UNI 6952

Surface Treatments & Coatings

Electro Less Nickel Plating Electro Cadmium Plating Dacromet 320 500 Coating Pickled Passivated Fasteners Silver Plating Nickel Plating Electro Zinc Cobalt Plating Electro Zinc Nickel Plating Ptfe Fluorocarbon Coating Aluminizing Ceramic Filled Fluorocarbon Coating

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S32520 Super Duplex Fasteners — Material Overview & Form Factors

S32520 Super Duplex is a high-performance alloy used wherever standard fasteners cannot meet the corrosion, temperature, or strength envelope. TorqBolt manufactures the full S32520 Super Duplex fastener range — bolts, nuts, screws, washers, studs, and custom forgings — under one ISO 9001:2015 quality system, with PED 2014/68/EU module-H qualification for pressure-equipment service.

Where S32520 Super Duplex Excels

S32520 Super Duplex is specified in oil & gas wellhead components, refinery heat exchangers, petrochemical reactors, power-generation turbines, marine offshore platforms, and pharmaceutical / food-grade processing. Its corrosion resistance, high-temperature strength, and weldability make it the default for service conditions outside the carbon and standard-stainless envelope.

Form Factors Available

Bolts — hex, heavy hex, socket, button, countersunk; M6–M100 / 1/4"–4"

Nuts — standard, heavy, jam, locking variants (nyloc, all-metal, flange)

Screws — cap, machine, set, shoulder, self-tapping; all common drive types

Washers — plain, spring, lock, Belleville, fender, tab

Studs & threaded rod — ASTM A193 / A320 / A453 / A540

Custom forgings — rings, blanks, shaped components to drawing

Standards & Certification

S32520 Super Duplex fasteners are supplied with EN 10204 3.1 (mill cert) or 3.2 (third-party witnessed) material test reports as standard. Additional certification packages: NACE MR0175 / ISO 15156 (sour service), NORSOK M-650 (subsea / topside), API 6A (wellhead), API 20E (subsea bolting), PED 2014/68/EU (pressure equipment). Third-party inspection by TUV, Lloyd's, BV, DNV, SGS, and Intertek arrangeable on order.

Lead Time & Sizes

Stock items in standard S32520 Super Duplex fastener sizes ship in 1–2 weeks; custom-manufactured items in 4–6 weeks subject to material availability. Diameters M6–M100 and 1/4"–4", lengths 10 mm–3000 mm covered in-house; oversize / non-standard sizes quoted to specification.

Duplex & Super Duplex Stainless Steels

Duplex stainless steels have a roughly 50/50 ferrite-austenite microstructure, doubling the yield strength of austenitic 304/316 grades while improving chloride pitting + stress-corrosion resistance. Duplex is the modern default for offshore platform fasteners, desalination plants, and sour-gas piping where austenitics fail to chloride SCC and martensitics fail to hydrogen embrittlement.

Duplex 2205 (UNS S32205 / S31803) is the standard grade with PREN ~35, suitable for chloride-bearing service to ~250°C. Super Duplex 2507 (S32750) and Zeron 100 (S32760) push PREN to 41-42 with higher Cr+Mo+N, qualifying for the most aggressive seawater + sour-well environments. SA-182 F51 / F53 / F55 / F60 are the ASME forged-flange equivalents.

Phase balance is critical: ferrite content must stay within 35-65% in weld + HAZ to maintain corrosion + impact properties (ASTM A923 testing). Solution anneal at 1040-1100°C followed by water quench locks the duplex microstructure. Fasteners ship per ASTM A276 / A479 with EN 10204 3.1 / 3.2 certs including ferrite count and Charpy impact at -46°C. NACE MR0175 / ISO 15156 sour-service certification is standard.

S32520 Super Duplex Fasteners