ASME SA240 304N Stainless Steel Plate | SA240 Type 304N
What is ASME SA240 304N Stainless Steel Plate?
As a professional stainless steel plate supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASME SA240 304N Stainless Steel Plate, also known as SA240 Type 304N.
ASME SA240 Type 304N is a nitrogen-alloyed version of the classic 18-8 austenitic stainless steel. By intentionally adding nitrogen (typically in the range of 0.10–0.16%), the grade achieves significantly higher yield and tensile strength compared with standard Type 304, while retaining excellent corrosion resistance, good formability, toughness and weldability. Nitrogen acts as a strong austenite stabilizer and solid-solution strengthener, allowing designers to use thinner sections or achieve higher load-bearing capacity without switching to more expensive alloys.
Type 304N is particularly useful in structural, pressure vessel and general fabrication applications where higher strength is desired but the full corrosion performance of molybdenum-bearing grades (316/316L) is not required. It remains non-magnetic in the annealed condition and offers the same general corrosion resistance profile as standard 304.
SHH STEEL supplies ASME SA240 304N 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 a full selection of surface finishes to meet project requirements.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASME SA240 / SA240M | Full compliance |
| Steel Grade | Type 304N (UNS S30451) | Confirmed |
| Product Form | Plate, Sheet | Available |
| Delivery Condition | Solution Annealed | Standard |
| Thickness Range | 1 mm – 80 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, BA, No.4, HL, Polished | Available |
| Certification | EN 10204 3.1 / ASME Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (Ladle Analysis) according to ASME SA240 Type 304N:
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 0.75 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 18.00 – 20.00 |
| Nickel (Ni) | 8.00 – 10.50 |
| Nitrogen (N) | 0.10 – 0.16 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 0.75 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.90 – 20.10 |
| Nickel (Ni) | 7.90 – 10.60 |
| Nitrogen (N) | 0.10 – 0.16 |
The intentional addition of nitrogen (0.10–0.16%) is the defining feature of Type 304N. Nitrogen significantly increases strength through solid-solution strengthening while helping to stabilize the austenitic structure.
Mechanical Properties
Room-Temperature Mechanical Properties (Annealed Condition)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 550 MPa (80 ksi) |
| Yield Strength (0.2%) | ≥ 240 MPa (35 ksi) |
| Elongation (in 50 mm) | ≥ 30% |
| Hardness | ≤ 217 HB / ≤ 95 HRB |
Compared with standard Type 304 (minimum yield strength 205 MPa), Type 304N offers a clear increase in both yield and tensile strength, allowing potential weight savings or higher design stresses in many applications.
Physical Properties
- Density: 7.93 g/cm³
- Melting Range: approximately 1400–1450°C
- Magnetic: Non-magnetic in the annealed condition
Material Comparison
| Grade | Key Feature | Strength Level | Primary Advantage | Typical Preference |
|---|---|---|---|---|
| SA240 Type 304 | Standard 18-8 | Baseline | Lowest cost, excellent formability | General purpose |
| SA240 Type 304L | Low carbon | Similar to 304 | Best as-welded intergranular corrosion resistance | Heavy welding |
| SA240 Type 304N | Nitrogen strengthened | Higher | Higher strength with same corrosion profile | Structural / pressure applications needing higher strength |
| SA240 Type 316L | Mo-bearing + low carbon | Similar to 304 | Better pitting resistance | Chloride environments |
| SA240 Type 2205 | Duplex | Much higher | High strength + excellent SCC resistance | High-strength chloride service |
ASME SA240 304N is selected when higher mechanical strength is required while staying within the 304 corrosion resistance family. For applications needing both higher strength and significantly better chloride resistance, astm a240 type 2205 stainless steel sheet plate is often considered. For maximum weldability in corrosive service, astm a240 type 304l stainless steel sheet plate remains the preferred low-carbon option.
Corrosion Resistance
In the annealed condition, ASME SA240 Type 304N offers corrosion resistance essentially equivalent to standard Type 304. It performs well in atmospheric, fresh-water, food-processing and many mild chemical environments. Resistance to intergranular corrosion is good in the annealed condition, although for heavy welded constructions in corrosive media the low-carbon grade 304L is still preferred.
Pitting and crevice corrosion resistance in chloride environments is similar to 304 and inferior to molybdenum-bearing grades such as 316L.
Weldability
ASME SA240 Type 304N has good weldability by all standard fusion and resistance welding methods. Matching or standard 308/308L filler metals are commonly used.
Because nitrogen increases strength, welding procedures should consider the higher strength of the base metal. The grade can be welded to other austenitic stainless steels and to carbon steels using appropriate procedures. Post-weld heat treatment is generally not required for most applications.
Heat Treatment
ASME SA240 Type 304N is supplied in the solution-annealed condition.
Recommended Solution Annealing Parameters
- Temperature range: 1010 – 1120°C (typically 1040 – 1100°C)
- Holding (soaking) time: – Plates ≤ 25 mm: minimum 10–20 minutes after the section reaches temperature – Plates 25–50 mm: minimum 20–40 minutes – Plates > 50 mm: 30–60 minutes or longer to ensure uniformity
- Cooling: Rapid cooling (water quench preferred for thicker plates) to retain nitrogen in solid solution and maximize strength and corrosion resistance.
Proper solution annealing is essential to achieve the full strength benefit of the nitrogen addition.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, annealed and pickled | SA240 304N No.1 – most common for industrial and pressure vessel plate |
| 2B | Cold-rolled, annealed, pickled, skin-passed | SA240 304N 2B – general fabrication |
| BA | Bright Annealed | SA240 304N BA – clean and decorative applications |
| No.4 | Brushed finish | SA240 304N No.4 – architectural and visible surfaces |
| HL | Hairline finish | SA240 304N HL – decorative panels |
| Polished | Mirror or custom polish | SA240 304N Polished – sanitary and high-end applications |
SHH STEEL regularly supplies ASME SA240 304N in No.1 and 2B finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASME SA240 304N Stainless Steel Plate conform to ASME SA240 and the general requirements of ASTM A480.
Typical available size range for SA240 304N plate:
- Thickness: 1 mm – 80 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 SA240 304N plate can be arranged for specific project needs. SHH STEEL provides precise dimensional control for both standard and custom-size SA240 304N plates.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| SA240 Type 304N | ASME SA240 | — |
| A240 Type 304N | ASTM A240 | Essentially identical |
| UNS S30451 | — | Unified Numbering System |
| 1.4315 / X5CrNiN19-9 | EN related | European nitrogen-strengthened equivalent |
| Related 304N grades | JIS / GB | Approximate national equivalents |
Related grades frequently evaluated with ASME SA240 304N include astm a240 type 304 stainless steel sheet plate, astm a240 type 304l stainless steel sheet plate, astm a240 type 316l stainless steel sheet plate, and astm a240 type 2205 stainless steel sheet plate.
Applications
ASME SA240 Type 304N is used where higher strength than standard 304 is required while maintaining good corrosion resistance. Typical applications of SA240 304N include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Pressure Vessels | SA240 304N vessels, columns and components requiring higher strength |
| Structural Fabrication | SA240 304N frames, supports and load-bearing structures |
| Chemical & Process Industry | SA240 304N tanks and equipment in mild to moderate environments |
| Food & Beverage | SA240 304N processing equipment and structural parts |
| General Fabrication | SA240 304N machinery components and fabricated structures |
| Transportation | SA240 304N structural and chassis-related components |
| Architecture | SA240 304N structural and decorative elements needing higher strength |
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 ASME SA240 Type 304N with the following advantages:
- Competitive mill-direct pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1 /3.2 ASME)
- Flexible dimensions and surface finishes (including SA240 304N No.1 and SA240 304N 2B)
- Technical support for strength-optimized material selection
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of SA240 304N over SA240 304?ype 304N contains intentional nitrogen addition that significantly increases yield and tensile strength while retaining essentially the same corrosion resistance as standard 304. SHH STEEL recommends 304N when higher mechanical properties are required without upgrading to molybdenum-bearing or duplex grades.
- Is SA240 304N more difficult to form or weld than standard 304?Formability remains good, although the higher strength requires slightly higher forming forces. Weldability is still excellent. SHH STEEL can provide guidance on fabrication practices for 304N.
- s ASME SA240 304N magnetic?Non-magnetic in the annealed condition. SHH STEEL supplies fully annealed material that meets this requirement.
- What is the density of SA240 Type 304N?7.93 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified ASME SA240 / ASTM A240 Type 304N?Yes, SHH STEEL commonly supplies dual-certified ASME SA240 / ASTM A240 Type 304N material.
Conclusion
ASME SA240 304N Stainless Steel Plate (SA240 Type 304N) is a nitrogen-strengthened austenitic stainless steel that delivers higher yield and tensile strength than standard 304 while maintaining good corrosion resistance, formability and weldability. It is an excellent choice when designers need increased mechanical performance within the familiar 304 corrosion resistance family.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASME SA240 Type 304N plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including SA240 304N No.1 and SA240 304N 2B), or a competitive quotation.
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