ASTM A240 2304 Stainless Steel Plate | A240 Type 2304
What is ASTM A240 2304 Stainless Steel Plate?
As a professional stainless steel plate supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASTM A240 2304 Stainless Steel Plate, also known as A240 Type 2304 or UNS S32304.
ASTM A240 Type 2304 is a lean duplex (austenitic-ferritic) stainless steel containing approximately 23% chromium, 4% nickel and nitrogen, with very low molybdenum content. The balanced duplex microstructure delivers significantly higher yield strength than standard austenitic grades such as 304L or 316L (nearly twice the yield strength), combined with good resistance to chloride stress corrosion cracking and adequate pitting resistance for many environments.
Type 2304 offers an attractive combination of mechanical properties, corrosion performance and cost. It is frequently selected as a higher-strength, more economical alternative to 304/304L or 316/316L in applications where the full pitting resistance of molybdenum-bearing duplex grades (such as 2205) is not required. Typical uses include chemical process equipment, pulp & paper, water treatment, storage tanks, structural components and architectural applications.
SHH STEEL supplies ASTM A240 2304 as true Mill Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, full heat traceability and shorter lead times. We offer a practical dimensional range and surface finishes suitable for industrial and fabricated applications.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASTM A240 / A240M | Full compliance |
| Steel Grade | Type 2304 (UNS S32304) | Confirmed |
| Product Form | Plate, Sheet | Available |
| Delivery Condition | Solution Annealed | Standard |
| Thickness Range | 1 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 2000–3000 mm | Available |
| Length | Up to 12000 mm or cut-to-length | Available |
| Surface Finish | No.1, 2B, and others on request | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (Ladle Analysis) according to ASTM A240 Type 2304 (UNS S32304):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.50 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 21.50 – 24.50 |
| Nickel (Ni) | 3.00 – 5.50 |
| Molybdenum (Mo) | 0.05 – 0.60 |
| Nitrogen (N) | 0.05 – 0.20 |
| Copper (Cu) | 0.05 – 0.60 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.50 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 21.50 – 24.50 |
| Nickel (Ni) | 3.00 – 5.50 |
| Molybdenum (Mo) | 0.05 – 0.60 |
| Nitrogen (N) | 0.05 – 0.20 |
| Copper (Cu) | 0.05 – 0.60 |
The lean duplex chemistry (high Cr + N, low Ni and very low Mo) produces a balanced austenite-ferrite microstructure that delivers high strength and good stress corrosion cracking resistance at a lower alloy cost than standard duplex 2205.
Mechanical Properties
Room-Temperature Mechanical Properties (Solution Annealed Condition)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 600 MPa (87 ksi) |
| Yield Strength (0.2%) | ≥ 400 MPa (58 ksi) |
| Elongation (in 50 mm) | ≥ 25% |
| Hardness | ≤ 290 HB |
Key Advantage The minimum yield strength of ASTM A240 2304 is approximately twice that of 304L/316L, allowing significant thickness reduction and weight savings in many designs.
Physical Properties
- Density: approximately 7.80 g/cm³
- Magnetic: Partially magnetic (duplex microstructure)
- Thermal Expansion: Lower than austenitic grades
Material Comparison
| Grade | Structure | Yield Strength (min) | PREN (approx.) | Primary Advantage | Typical Preference |
|---|---|---|---|---|---|
| A240 Type 304L | Austenitic | 170 MPa | ≈ 18–20 | Excellent formability & weldability | General corrosive service |
| A240 Type 316L | Austenitic | 170 MPa | ≈ 24 | Better pitting resistance | Moderate chloride service |
| A240 Type 2304 | Lean Duplex | 400 MPa | ≈ 26 | High strength + good SCC resistance + lower cost | Cost-effective high-strength alternative to 304/316 |
| A240 Type 2205 | Duplex | 450 MPa | ≥ 35 | Higher pitting & crevice corrosion resistance | More severe chloride service |
| A240 Type 2507 | Super Duplex | 550 MPa | ≥ 40–43 | Highest strength & corrosion resistance | Seawater / most severe chloride service |
ASTM A240 2304 is selected when higher strength and better stress corrosion cracking resistance than 304L/316L are required, while the full pitting resistance of 2205 is not necessary. It is a cost-effective lean duplex solution. For more aggressive chloride environments, astm a240 type 2205 stainless steel sheet plate or astm a240 type 2507 stainless steel sheet plate should be considered. Related austenitic options include astm a240 type 304l stainless steel sheet plate and astm a240 type 316l stainless steel sheet plate.
Corrosion Resistance
ASTM A240 Type 2304 offers good resistance to general corrosion in many chemical environments and significantly better resistance to chloride stress corrosion cracking than austenitic grades 304L and 316L. Its pitting resistance (PREN ≈ 26) is higher than 304L but lower than standard duplex 2205.
It performs well in neutral and alkaline media, many organic acids, and moderate chloride environments. It is not intended for severe seawater or highly aggressive chloride service, where higher-alloy duplex or super duplex grades are preferred.
Weldability
ASTM A240 Type 2304 offers good resistance to general corrosion in many chemical environments and significantly better resistance to chloride stress corrosion cracking than austenitic grades 304L and 316L. Its pitting resistance (PREN ≈ 26) is higher than 304L but lower than standard duplex 2205.
It performs well in neutral and alkaline media, many organic acids, and moderate chloride environments. It is not intended for severe seawater or highly aggressive chloride service, where higher-alloy duplex or super duplex grades are preferred.
Weldability
ASTM A240 Type 2304 has good weldability for a duplex stainless steel. Matching lean duplex or 2209-type filler metals are commonly used.
Key points:
- Heat input and interpass temperature should be controlled (typically interpass ≤ 150°C).
- Proper shielding is important to maintain the balanced microstructure and corrosion resistance.
- Post-weld heat treatment is generally not required for most applications.
- When correctly welded, the joint retains high strength and good corrosion performance.
Heat Treatment
ASTM A240 Type 2304 is supplied in the solution-annealed condition.
Recommended Solution Annealing Parameters
- Temperature range: 950 – 1050°C (typically 1000 – 1050°C)
- Holding (soaking) time: – Plates ≤ 25 mm: minimum 15–30 minutes after the section reaches temperature – Plates 25–50 mm: minimum 30–45 minutes – Thicker plates: longer times to ensure uniformity
- Cooling: Rapid cooling (water quenching preferred) is essential to preserve the balanced duplex microstructure and optimum corrosion resistance. Slow cooling can lead to formation of intermetallic phases that reduce toughness and corrosion performance.
Proper solution annealing and rapid cooling are critical for Type 2304 performance.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, annealed and pickled | A240 2304 No.1 – most common for industrial and pressure vessel plate |
| 2B | Cold-rolled, annealed, pickled, skin-passed | A240 2304 2B – thinner plates and general fabrication |
| No.4 | Brushed finish | A240 2304 No.4 – when improved surface appearance is required |
| Special | Ground or custom finishes | A240 2304 Special – on request |
SHH STEEL regularly supplies ASTM A240 2304 in No.1 and 2B finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASTM A240 2304 Stainless Steel Plate conform to ASTM A240 and the general requirements of ASTM A480.
Typical available size range for A240 2304 plate:
- Thickness: 1 mm – 50 mm (thicker plates available on request)
- Width: up to 2000–3000 mm
- Length: up to 12000 mm or cut-to-length according to customer requirements
Thickness, width, length and flatness tolerances are controlled within standard limits. Tighter tolerances for A240 2304 plate can be arranged for specific project needs. SHH STEEL provides precise dimensional control for both standard and custom-size A240 2304 plates.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| A240 Type 2304 | ASTM A240 | — |
| SA240 Type 2304 | ASME SA240 | Essentially identical |
| UNS S32304 | — | Unified Numbering System |
| 1.4362 / X2CrNiN23-4 | EN 10088-2 | European equivalent |
| Related lean duplex | JIS / GB | Approximate national equivalents |
Related grades frequently evaluated with ASTM A240 2304 include astm a240 type 2205 stainless steel sheet plate, astm a240 type 304l stainless steel sheet plate, astm a240 type 316l stainless steel sheet plate, and astm a240 type 2507 stainless steel sheet plate.
Applications
ASTM A240 Type 2304 is used where higher strength and better stress corrosion cracking resistance than 304/316 are required at an economical cost. Typical applications of A240 2304 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Chemical Processing | A240 2304 tanks, vessels, piping and process equipment |
| Pulp & Paper | A240 2304 digesters, bleaching equipment and structural parts |
| Water Treatment & Desalination | A240 2304 tanks, piping and structural components |
| Storage Tanks | A240 2304 storage and process tanks |
| Architecture & Construction | A240 2304 structural and cladding components |
| Food & Beverage | A240 2304 equipment in moderate environments |
| General Fabrication | A240 2304 high-strength welded structures |
Why Choose SHH STEEL
SHH STEEL is a China Mill-Direct Supply and Mill Direct Exporter of stainless steel plate. We maintain long-term strategic cooperation with major Chinese stainless steel mills and supply ASTM A240 Type 2304 with the following advantages:
- Competitive mill-direct pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1/3.2)
- Flexible dimensions and surface finishes (including A240 2304 No.1 and A240 2304 2B)
- Technical support for lean duplex material selection and fabrication
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of A240 2304 over A240 304L or 316L?Type 2304 offers approximately twice the yield strength and significantly better resistance to chloride stress corrosion cracking, while remaining cost-competitive. SHH STEEL recommends 2304 when higher strength and improved SCC resistance are required without the cost of higher-alloy duplex grades.
- How does A240 2304 compare with A240 2205?Type 2304 is a lean duplex with lower molybdenum content, offering lower pitting resistance but better economy. Type 2205 provides higher PREN and better performance in more severe chloride environments. SHH STEEL can help select the appropriate grade based on the specific service conditions.
- Is ASTM A240 2304 magnetic?Yes, it is partially magnetic due to its duplex (austenite + ferrite) microstructure. SHH STEEL supplies material that meets this characteristic.
- What is the density of A240 Type 2304?Approximately 7.80 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified ASTM A240 / ASME SA240 Type 2304?Yes, SHH STEEL commonly supplies dual-certified ASTM A240 / ASME SA240 Type 2304 material.
Conclusion
ASTM A240 2304 Stainless Steel Plate (A240 Type 2304 / UNS S32304) is a lean duplex stainless steel that delivers high strength, good resistance to stress corrosion cracking and attractive economy. It is an excellent cost-effective alternative to 304L/316L in many chemical, water treatment, pulp & paper and structural applications.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASTM A240 Type 2304 plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including A240 2304 No.1 and A240 2304 2B), or a competitive quotation.
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