Related Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASTM A1082/A1082M Grade S31260 | Alloy 926 Super Austenitic Steel
Exceptional corrosion resistance for acidic chloride and high-stress environments
Grade S31260 (UNS S31260) is a premium super austenitic stainless steel, commonly known as Alloy 926 or ASTM A1082/A1082M F44, featuring 20% chromium, 25% nickel, and 6% molybdenum with nitrogen additions to deliver exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in aggressive acidic and chloride-rich environments. With a PREN value of ~43, S31260 outperforms standard austenitic grades like 316L and is widely utilized in offshore oil and gas production, chemical processing equipment, flue gas desulfurization systems, pulp and paper bleaching plants, and seawater cooling systems. This super austenitic grade maintains excellent mechanical properties and fabricability, offering a cost-effective alternative to nickel-based alloys in applications requiring high localized corrosion resistance and superior structural integrity.
ASTM A1082/A1082M Grade S31260 Chemical RequirementsA
| Grades | UNS Designation | Type | C | Mn | P | S | Si | Cr | Ni | Mo | N | Other ElementsB |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ASTM A1082/A1082M Super Austenitic Stainless Steel Grades | S31260 | . . . | 0.030 | 1.00 | 0.030 | 0.030 | 0.75 | 24.0-26.0 | 5.5-7.5 | 2.5-3.5 | 0.10-0.30 | Cu 0.20-0.80,W 0.10-0.50 |
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ASTM A1082/A1082M Grade S31260 Mechanical Properties
| UNS Designation | Solution Temperature, °F [°C] (B, C) | Tensile Strength, min, ksi [MPa] | Yield Strength, 0.2% offset, min, ksi [MPa] | Elongation in 2" [50 mm] or 4D, min, % | Rockwell HRC, max | Brinell max (D) |
|---|---|---|---|---|---|---|
| S31260 | 1870 to 2010 [1020 to 1100] | 100 [690] | 70 [485] | 20 | 31 | 297 |
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ASTM A1082/A1082M Markings
| UNS Designation | Grade Symbol |
|---|---|
| S31260 | TB 31260 |
Frequently Asked Questions
What is Alloy 926 (S31260)?
Alloy 926 (S31260) is a stainless steel grade covered under ASTM A1082/A1082M for high-strength bolting in special-purpose applications such as pressure vessels. UNS designation S31260. Available as bolts, studs, screws and nuts manufactured by TorqBolt for global oil/gas/nuclear/power/marine sectors.
What are the mechanical properties of Alloy 926 (S31260) per ASTM A1082?
Mechanical property requirements for S31260 are defined in ASTM A1082 Table 2 (PH grade solution treatment) or Table 4 (duplex annealed condition). Properties vary by treatment condition - refer to the bolting specification for the H-condition (PH) or annealed yield/tensile/elongation/hardness requirements applicable to your order.
Is Alloy 926 (S31260) suitable for sour service (NACE MR0175)?
Refer to NACE MR0175 / ISO 15156 Tables A.16-A.19. Most A1082 duplex grades are permitted at ≤28 HRC; PH grades require condition-specific qualification (typically H1150 for 17-4 PH at 28 HRC). TorqBolt supplies sour-service certified product on request with full PMI + hardness traceability.
What ASME / ISO dimensional standards can Alloy 926 (S31260) be supplied to?
This grade is available across the full ASME and ISO bolting dimensional standards covered on this site - ASME B18.2.1 (hex bolts, hex cap screws, lag screws), B18.2.2 (hex nuts, square nuts, lock nuts), B18.3 (socket head cap screws), B18.31.2 (clamping studs), B16.5 (flange stud bolts), ISO 4032 / 4033 / 4035 (metric nuts), and metric B18.2.3.xM / B18.2.4.xM series.
References & Standards
- ASTM A1082 / A1082M - Standard Specification for High-Strength Precipitation-Hardening and Duplex Stainless Steel Bolting for Special-Purpose Applications (current edition 2016, active)
- ASTM A962 / A962M - General Requirements for Special-Purpose Bolting Materials
- ASTM A370 - Mechanical Testing of Steel Products
- NACE MR0175 / ISO 15156 - Sour-service hardness limits for petroleum & natural gas industries
- ASME B18 series - Dimensional standards for bolts, screws, nuts, studs
- ISO 4032 / 4033 / 4035 - Metric hexagon nut dimensional standards
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