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 S32304 | Lean Duplex 2304 Stainless Steel
High-strength lean duplex steel with corrosion resistance comparable to 316L
Grade S32304 (UNS S32304) is a low-alloyed lean duplex stainless steel, commonly known as Duplex 2304, featuring 23% chromium and 4% nickel without molybdenum additions to provide high strength and excellent resistance to stress corrosion cracking (SCC). Designated as ASTM A1082/A1082M F68, this grade offers corrosion resistance comparable to standard 316L austenitic stainless steel but with nearly double the yield strength, allowing for significant material savings in structural and pressure-containing applications. S32304 is widely utilized in storage tanks, heat exchangers, pulp and paper processing, and desalination systems where cost-efficiency and mechanical durability are paramount. Its dual-phase microstructure ensures high toughness and excellent weldability, making it a versatile alternative to nickel-heavy austenitic alloys in moderately corrosive industrial environments.
ASTM A1082/A1082M Grade S32304 Chemical RequirementsA
| Grades | UNS Designation | Type | C | Mn | P | S | Si | Cr | Ni | Mo | N | Other ElementsB |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ASTM A1082/A1082M Duplex (Ferritic-Austenitic) Grades | S32304 | 2304 | 0.030 | 2.50 | 0.040 | 0.030 | 1.00 | 21.5-24.5 | 3.0-5.5 | 0.05-0.60 | 0.05-0.20 | Cu 0.05-0.60 |
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ASTM A1082/A1082M Grade S32304 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) |
|---|---|---|---|---|---|---|
| S32304 | 1800 [980] | 90 [620] | 65 [450] | 18 | 32 | 302 |
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ASTM A1082/A1082M Markings
| UNS Designation | Type | Grade Symbol |
|---|---|---|
| S32304 | 2304 | TB 32304 |
Frequently Asked Questions
What is Lean Duplex 2304 (S32304)?
Lean Duplex 2304 (S32304) is a stainless steel grade covered under ASTM A1082/A1082M for high-strength bolting in special-purpose applications such as pressure vessels. UNS designation S32304. Available as bolts, studs, screws and nuts manufactured by TorqBolt for global oil/gas/nuclear/power/marine sectors.
What are the mechanical properties of Lean Duplex 2304 (S32304) per ASTM A1082?
Mechanical property requirements for S32304 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 Lean Duplex 2304 (S32304) 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 Lean Duplex 2304 (S32304) 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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