ASME SA240 304LN Stainless Steel Plate | SA240 Type 304LN
What is ASME SA240 304LN 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 304LN Stainless Steel Plate, also known as SA240 Type 304LN.
ASME SA240 Type 304LN is a dual-improved version of the classic 18-8 austenitic stainless steel. It combines a very low carbon content (≤ 0.030%) with intentional nitrogen addition (typically 0.10–0.16%). The low carbon content provides outstanding resistance to intergranular corrosion in the as-welded condition, while the nitrogen significantly increases yield and tensile strength compared with standard Type 304L.
This combination makes Type 304LN an excellent choice for welded pressure vessels, structural components and process equipment where both higher mechanical strength and superior as-welded corrosion performance are required. It retains the excellent formability, toughness and fabricability of the austenitic family and remains non-magnetic in the annealed condition.
SHH STEEL supplies ASME SA240 304LN 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 304LN (UNS S30453) | 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 304LN:
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| 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 – 12.00 |
| Nitrogen (N) | 0.10 – 0.16 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| 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 – 12.10 |
| Nitrogen (N) | 0.10 – 0.16 |
The combination of ultra-low carbon (≤ 0.030%) and controlled nitrogen (0.10–0.16%) is the defining feature of Type 304LN. Low carbon ensures excellent resistance to intergranular corrosion after welding, while nitrogen provides solid-solution strengthening.
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 304L (minimum yield strength 170 MPa), Type 304LN offers a substantial increase in both yield and tensile strength, while retaining the superior as-welded corrosion resistance of the low-carbon grade.
Physical Properties
- Density: 7.93 g/cm³
- Melting Range: approximately 1400–1450°C
- Magnetic: Non-magnetic in the annealed condition
Material Comparison
| Grade | Carbon | Nitrogen | Strength Level | Primary Advantage | Typical Preference |
|---|---|---|---|---|---|
| SA240 Type 304L | ≤ 0.030% | Low | Baseline | Best as-welded intergranular corrosion resistance | Heavy welding, maximum corrosion resistance |
| SA240 Type 304N | ≤ 0.08% | 0.10–0.16% | Higher | Higher strength | Higher strength, moderate welding |
| SA240 Type 304LN | ≤ 0.030% | 0.10–0.16% | Higher | Higher strength + excellent as-welded performance | Welded structures needing higher strength |
| SA240 Type 316L | ≤ 0.030% | Low | Similar to 304L | Better pitting resistance | Chloride environments |
| SA240 Type 2205 | ≤ 0.030% | High | Much higher | High strength + excellent SCC resistance | High-strength chloride service |
ASME SA240 304LN is the preferred choice when both higher mechanical strength and superior resistance to intergranular corrosion after welding are required within the 304 family. For applications needing significantly better chloride resistance, astm a240 type 316l stainless steel sheet plate or astm a240 type 2205 stainless steel sheet plate should be considered. For maximum economy in non-critical welded service, standard astm a240 type 304l stainless steel sheet plate remains widely used.
Corrosion Resistance
In the annealed condition, ASME SA240 Type 304LN offers corrosion resistance essentially equivalent to Type 304L. The very low carbon content provides outstanding resistance to intergranular corrosion in the as-welded condition, eliminating the need for post-weld annealing in most applications.
It performs well in atmospheric, fresh-water, food-processing and many mild chemical environments. Pitting and crevice corrosion resistance in chloride media is similar to 304L and inferior to molybdenum-bearing grades.
Weldability
ASME SA240 Type 304LN possesses excellent weldability by all standard fusion and resistance welding methods. Because of its low carbon content, it is highly suitable for multi-pass welding in corrosive service.
Matching low-carbon or nitrogen-bearing filler metals (E308L / ER308L or appropriate nitrogen-strengthened consumables) are commonly used. The grade can be welded to other austenitic stainless steels and to carbon steels using appropriate procedures. Post-weld heat treatment is generally unnecessary for corrosion resistance purposes.
Heat Treatment
ASME SA240 Type 304LN 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 both strength and corrosion resistance.
Proper solution annealing is essential to achieve the full benefit of the nitrogen strengthening while maintaining the low-carbon advantages.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, annealed and pickled | SA240 304LN No.1 – most common for industrial and pressure vessel plate |
| 2B | Cold-rolled, annealed, pickled, skin-passed | SA240 304LN 2B – general fabrication |
| BA | Bright Annealed | SA240 304LN BA – clean and decorative applications |
| No.4 | Brushed finish | SA240 304LN No.4 – architectural and visible surfaces |
| HL | Hairline finish | SA240 304LN HL – decorative panels |
| Polished | Mirror or custom polish | SA240 304LN Polished – sanitary and high-end applications |
SHH STEEL regularly supplies ASME SA240 304LN in No.1 and 2B finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASME SA240 304LN Stainless Steel Plate conform to ASME SA240 and the general requirements of ASTM A480.
Typical available size range for SA240 304LN 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 304LN plate can be arranged for specific project needs. SHH STEEL provides precise dimensional control for both standard and custom-size SA240 304LN plates.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| SA240 Type 304LN | ASME SA240 | — |
| A240 Type 304LN | ASTM A240 | Essentially identical |
| UNS S30453 | — | Unified Numbering System |
| 1.4311 / X2CrNiN18-10 | EN related | European low-carbon nitrogen-strengthened equivalent |
| Related 304LN grades | JIS / GB | Approximate national equivalents |
Related grades frequently evaluated with ASME SA240 304LN include astm a240 type 304l stainless steel sheet plate, astm a240 type 304n 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 304LN is used where both higher strength and excellent as-welded corrosion resistance are required. Typical applications of SA240 304LN include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Pressure Vessels | SA240 304LN vessels, columns and components requiring higher strength and weldability |
| Structural Fabrication | SA240 304LN frames, supports and load-bearing welded structures |
| Chemical & Process Industry | SA240 304LN tanks and equipment in mild to moderate environments |
| Food & Beverage | SA240 304LN processing equipment and welded structures |
| General Fabrication | SA240 304LN machinery components and fabricated structures |
| Transportation | SA240 304LN structural and chassis-related components |
| Architecture | SA240 304LN structural elements needing higher strength and corrosion resistance |
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 304LN 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 304LN No.1 and SA240 304LN 2B)
- Technical support for strength- and weldability-optimized material selection
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of SA240 304LN over SA240 304L?Type 304LN contains intentional nitrogen addition that significantly increases yield and tensile strength while retaining the excellent as-welded intergranular corrosion resistance of the low-carbon grade. SHH STEEL recommends 304LN when higher mechanical properties are required in welded constructions.
- What is the difference between SA240 304N and SA240 304LN?Type 304LN has a much lower carbon content (≤ 0.030%) for superior resistance to intergranular corrosion after welding, while Type 304N has higher carbon (up to 0.08%). Both are nitrogen-strengthened. SHH STEEL can supply both grades according to project requirements.
- Is ASME SA240 304LN magnetic?Non-magnetic in the annealed condition. SHH STEEL supplies fully annealed material that meets this requirement.
- What is the density of SA240 Type 304LN?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 304LN?Yes, SHH STEEL commonly supplies dual-certified ASME SA240 / ASTM A240 Type 304LN material.
Conclusion
ASME SA240 304LN Stainless Steel Plate (SA240 Type 304LN) is a low-carbon nitrogen-strengthened austenitic stainless steel that successfully combines higher mechanical strength with excellent resistance to intergranular corrosion after welding. It is an ideal choice for welded pressure vessels, structural components and process equipment that require both elevated strength and reliable as-welded corrosion performance.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASME SA240 Type 304LN plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including SA240 304LN No.1 and SA240 304LN 2B), or a competitive quotation.
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