ASTM A240 Type 304LN Stainless Steel Sheet & Plate
What is ASTM A240 Type 304LN Stainless Steel Sheet and Plate?
As a professional production and export supplier, SHH STEEL is pleased to offer ASTM A240 Type 304LN Stainless Steel Sheet and Plate. Also known as UNS S30453 or SS304LN, this grade is a low-carbon, nitrogen-alloyed version of the classic 18-8 austenitic stainless steel family.
Type 304LN is designed to provide the superior resistance to intergranular corrosion of Type 304L while delivering higher mechanical strength through intentional nitrogen addition (0.10–0.16%). The low carbon content (maximum 0.030%) minimizes carbide precipitation during welding, making it highly suitable for welded structures that will be exposed to corrosive environments.
SHH STEEL supplies ASTM A240 Type 304LN in both sheet and plate forms, covering a wide thickness range from thin cold-rolled sheets to heavy hot-rolled plates. The material is typically delivered in the solution-annealed condition with excellent formability, toughness, and corrosion resistance. Full Mill Test Certificates (EN 10204 3.1 or 3.2) are provided with every shipment to ensure complete traceability and compliance with international standards.
Material Specification
ASTM A240 Type 304LN stainless steel sheet and plate are produced in accordance with ASTM A240/A240M and the corresponding ASME SA-240 specification. This standard covers chromium and chromium-nickel stainless steel plate, sheet, and strip intended for pressure vessels and general applications.
SHH STEEL supplies the material in the annealed condition. Common surface finishes include 2B, No.1, BA (Bright Annealed), HL (Hairline), and No.4. Thicknesses range from 0.4 mm for thin sheets up to 100 mm for heavy plates. Widths up to 2500 mm and lengths up to 12000 mm are available, with custom dimensions offered upon request.
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASTM A240 / ASME SA-240 Type 304LN | Full compliance |
| Product Form | Sheet and Plate | Both available |
| Thickness Range | 0.4 mm – 100 mm | Custom sizes available |
| Width / Length | Up to 2500 mm / 12000 mm | Custom fabrication supported |
| Surface Finish | 2B, No.1, BA, HL, No.4 | Multiple options |
| Heat Treatment Condition | Solution Annealed | Standard supply condition |
| Certification | EN 10204 3.1 / 3.2 | Available |
ASTM A240 Type 304LN Chemical Composition
The chemical composition of ASTM A240 Type 304LN is carefully controlled. The low carbon content ensures excellent resistance to intergranular corrosion after welding, while the controlled nitrogen addition increases strength without significantly reducing ductility.
| Element | Content (%) | Standard Limit | Role |
|---|---|---|---|
| Carbon (C) | ≤ 0.030 | 0.030 max | Minimizes intergranular corrosion risk |
| Manganese (Mn) | ≤ 2.00 | 2.00 max | Deoxidation and strength |
| Phosphorus (P) | ≤ 0.045 | 0.045 max | Impurity control |
| Sulfur (S) | ≤ 0.030 | 0.030 max | Cleanliness and weldability |
| Silicon (Si) | ≤ 0.75 | 0.75 max | Deoxidation |
| Chromium (Cr) | 18.00 – 20.00 | 18.00 – 20.00 | Corrosion and oxidation resistance |
| Nickel (Ni) | 8.00 – 12.00 | 8.00 – 12.00 | Austenite stability and toughness |
| Nitrogen (N) | 0.10 – 0.16 | 0.10 – 0.16 | Strengthening element |
ASTM A240 Type 304LN Mechanical Properties
In the solution-annealed condition, ASTM A240 Type 304LN offers a balanced combination of higher strength than standard 304L and excellent ductility.
| Property | Value | Test Method |
|---|---|---|
| Tensile Strength | ≥ 515 MPa (75 ksi) | ASTM A370 |
| Yield Strength (0.2% Offset) | ≥ 205 MPa (30 ksi) | ASTM A370 |
| Elongation in 50 mm | ≥ 40% | ASTM A370 |
| Hardness | ≤ 217 HB / ≤ 95 HRB | ASTM E10/E18 |
| Density | 8.00 g/cm³ | — |
Note: Actual values on Mill Test Certificates are typically higher than the minimum requirements.
Delivery Conditions
SHH STEEL supplies ASTM A240 Type 304LN primarily in the solution-annealed and pickled condition. The most common surface finishes are:
- 2B: Cold-rolled, annealed, pickled and skin-passed (most popular for sheet)
- No.1: Hot-rolled, annealed and pickled (standard for plate)
- BA (Bright Annealed): Highly reflective finish
- HL (Hairline): Brushed finish for architectural applications
- No.4: Polished finish
Protective PVC film can be applied on one or both sides to prevent surface damage during transportation and fabrication.
Tolerances
Dimensional tolerances for ASTM A240 Type 304LN sheet and plate are governed by ASTM A480/A480M, which is the general requirements standard referenced by ASTM A240.
Thickness Tolerances Thickness tolerances vary according to thickness and product form (sheet or plate). For cold-rolled sheet, tolerances are relatively tight. For hot-rolled plate, wider tolerances apply as thickness increases. SHH STEEL can supply material with standard ASTM A480 tolerances or tighter tolerances upon request for precision applications.
Width and Length Tolerances
- Standard width tolerance is typically +6 mm / –0 mm or better, depending on width and thickness.
- Length tolerance is normally +10 mm / –0 mm for cut lengths, with closer tolerances available.
- Custom cutting to precise dimensions is offered.
Flatness Flatness tolerances follow ASTM A480 requirements. For critical applications requiring superior flatness (e.g., laser cutting or precision fabrication), SHH STEEL can provide material with improved flatness levels.
Edge Condition
- Sheet: Usually supplied with mill edge or slit edge
- Plate: Supplied with mill edge, sheared edge, or plasma/laser cut edge according to customer requirements
Customers requiring special tolerance levels (e.g., EN 10029 Class B or tighter) should specify this at the time of enquiry.
Weldability
ASTM A240 Type 304LN offers excellent weldability, which is one of its major advantages over standard Type 304.
The combination of very low carbon content (≤ 0.030%) and controlled nitrogen addition provides outstanding resistance to intergranular corrosion in the as-welded condition. This makes 304LN particularly suitable for welded pressure vessels, tanks, and process equipment that cannot be post-weld heat treated.
Key Welding Characteristics:
- Preheating is generally not required.
- Post-weld heat treatment is usually unnecessary for most applications.
- The material can be welded by all common fusion welding methods, including:
- Gas Tungsten Arc Welding (GTAW / TIG)
- Gas Metal Arc Welding (GMAW / MIG)
- Shielded Metal Arc Welding (SMAW)
- Plasma Arc Welding
- Submerged Arc Welding (for thicker sections)
Recommended Filler Metals:
- ER308L or ER308LSi (most common)
- ER308LN (when matching nitrogen-strengthened properties is desired)
Welding Precautions:
- Clean the joint thoroughly to remove oil, grease, and contaminants.
- Use low-heat-input techniques when possible to minimize distortion.
- After welding, it is recommended to perform proper cleaning (pickling or mechanical cleaning) followed by passivation to restore full corrosion resistance, especially in aggressive environments.
Overall, Type 304LN is considered one of the most weldable austenitic stainless steels available for applications requiring both high strength and excellent corrosion resistance after welding.
Equivalent Material Grades ASTM A240 Type 304LN
ASTM A240 Type 304LN has well-established international equivalents:
| Grade | Standard | Designation |
|---|---|---|
| Type 304LN | ASTM A240 / ASME SA-240 | — |
| UNS S30453 | Unified Numbering System | S30453 |
| 1.4311 | EN 10088 / EN 10028-7 | X2CrNiN18-10 |
| SUS304LN | JIS G4304 / G4305 | — |
| 022Cr19Ni10N | GB/T 20878 / GB/T 4237 / GB/T 3280 | Chinese National Standard |
| 00Cr18Ni10N | Older Chinese designation | — |
| 304S61 / 304S62 | British Standards | — |
Supplementary Requirements
Additional testing and requirements available upon request include:
- Intergranular corrosion testing (ASTM A262 Practice E)
- Ultrasonic examination
- Product analysis
- Elevated temperature tensile testing
- Charpy impact testing
- Dual certification with other related grades when chemistry permits
ASTM A240 Type 304LN Applications
Due to its combination of low carbon content, nitrogen strengthening, excellent weldability, and good corrosion resistance, ASTM A240 Type 304LN is widely used in:
- Welded pressure vessels and storage tanks
- Chemical and petrochemical process equipment
- Food and beverage processing equipment
- Pharmaceutical and biotechnology equipment
- Heat exchangers and condensers
- Architectural and structural applications requiring higher strength
- Components that will be welded and exposed to corrosive media
Why Choose SHH STEEL
SHH STEEL is a professional exporter of ASTM A240 Type 304LN stainless steel sheet and plate. We offer:
- Strict quality control and full traceability
- Competitive pricing from Chinese mills
- Flexible custom sizes and surface finishes
- Reliable global logistics and documentation support
- Technical assistance for material selection and fabrication
All material is supplied with complete Mill Test Certificates and can meet additional third-party inspection requirements when requested.
FAQ
- What is the main difference between 304L and 304LN?Both have low carbon content (≤0.030%). Type 304LN contains additional nitrogen (0.10–0.16%), which increases yield and tensile strength compared with standard 304L while retaining excellent intergranular corrosion resistance.
- Is ASTM A240 Type 304LN suitable for welded pressure vessels?Yes. Due to its low carbon content and good weldability, it is one of the preferred grades for welded pressure vessels and tanks that operate in corrosive environments.
- What is the Chinese equivalent of ASTM A240 Type 304LN?The main Chinese designation is 022Cr19Ni10N (also written as 00Cr18Ni10N in older standards).
- What is the density of ASTM A240 Type 304LN?Approximately 8.00 g/cm³.
- Can you supply dual-certified 304L/304LN material?In some cases, yes, if the chemical composition and mechanical properties meet the requirements of both grades. Please contact us for confirmation.
Conclusion
SHH STEEL’s ASTM A240 Type 304LN Stainless Steel Sheet and Plate deliver an excellent combination of higher strength, outstanding weldability, and superior resistance to intergranular corrosion. With precise quality control, flexible sizing options, detailed technical support, and reliable global supply capability, we provide trusted solutions for pressure vessels, process equipment, and demanding industrial applications worldwide.
Contact SHH STEEL today for your ASTM A240 Type 304LN requirements.
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