ASME SA240 409L Stainless Steel Plate | SA240 Type 409L
What is ASME SA240 409L 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 409L Stainless Steel Plate, also known as SA240 Type 409L.
ASME SA240 Type 409L is the low-carbon version of the widely used titanium-stabilized ferritic stainless steel Type 409. With a significantly reduced carbon content (typically ≤ 0.03%), Type 409L offers improved weldability and superior resistance to intergranular corrosion after welding compared with standard Type 409. It retains the good high-temperature oxidation resistance, excellent formability and low cost that have made the 409 family the global standard for automotive exhaust systems.
Type 409L is magnetic and non-hardenable by heat treatment. It is particularly preferred in applications involving more critical welding, longer exhaust system life requirements, or slightly more demanding corrosion conditions, while still remaining highly economical compared with higher-chromium ferritic or austenitic grades.
SHH STEEL supplies ASME SA240 409L 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 both coil and plate products with surface finishes suitable for automotive and industrial applications.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASME SA240 / SA240M | Full compliance |
| Steel Grade | Type 409L (UNS S40903) | Confirmed |
| Product Form | Plate, Sheet, Coil | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.4 mm – 6.0 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500 mm (wider on request) | Available |
| Length | Coil or cut-to-length | Available |
| Surface Finish | 2B, No.1, and others on request | Available |
| Certification | EN 10204 3.1 / ASME Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (Ladle Analysis) according to ASME SA240 Type 409L (typical / UNS S40903 related):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.03 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.020 |
| Chromium (Cr) | 10.50 – 11.75 |
| Nickel (Ni) | ≤ 0.50 |
| Titanium (Ti) | ≥ 6 × (C + N) and ≤ 0.75 |
| Nitrogen (N) | ≤ 0.030 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.03 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.020 |
| Chromium (Cr) | 10.40 – 11.85 |
| Nickel (Ni) | ≤ 0.50 |
| Titanium (Ti) | ≥ 6 × (C + N) and ≤ 0.75 |
| Nitrogen (N) | ≤ 0.030 |
The combination of very low carbon (≤ 0.03%) and titanium stabilization is the defining feature of Type 409L. This provides significantly better resistance to intergranular corrosion after welding and improved overall weldability compared with standard Type 409.
Mechanical Properties
Annealed Condition (typical)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 380 MPa (55 ksi) |
| Yield Strength (0.2%) | ≥ 170 MPa (25 ksi) |
| Elongation (in 50 mm) | ≥ 20% |
| Hardness | ≤ 179 HB |
Physical Properties
- Density: approximately 7.75 g/cm³
- Magnetic: Magnetic in all conditions
- Melting Range: approximately 1480–1530°C
Type 409L cannot be hardened by heat treatment. It retains the excellent formability that is essential for complex automotive exhaust components.
Material Comparison
| Grade | Carbon Level | Stabilization | Key Advantage | Typical Preference |
|---|---|---|---|---|
| SA240 Type 409 | ≤ 0.08% | Titanium | Lowest cost + good oxidation resistance | Standard automotive exhaust |
| SA240 Type 409L | ≤ 0.03% | Titanium | Improved weldability & intergranular corrosion resistance | Higher-quality / welded exhaust systems |
| SA240 Type 439 | Low | Titanium | Higher Cr + better corrosion & oxidation resistance | More demanding exhaust systems |
| SA240 Type 441 | Low | Nb + Ti | Higher strength & temperature capability | Premium exhaust applications |
| SA240 Type 430 | ≤ 0.12% | None | Better general corrosion resistance | Appliances and general use |
ASME SA240 409L is the preferred choice when improved weldability and better resistance to intergranular corrosion are required over standard 409, while still maintaining the lowest possible material cost. For higher chromium and better overall corrosion/oxidation performance, astm a240 type 439 stainless steel sheet plate is commonly selected. Related grades include astm a240 type 409 stainless steel sheet plate and astm a240 type 441 stainless steel sheet plate.
Corrosion Resistance
ASME SA240 Type 409L offers moderate corrosion resistance in atmospheric and mild environments, with its primary strength being high-temperature oxidation and scaling resistance. The low carbon content and titanium stabilization provide better resistance to intergranular corrosion after welding compared with standard Type 409.
It performs well in the hot, condensate and cyclic conditions of automotive exhaust systems. It is not suitable for severe chloride environments or strong acids.
Weldability
ASME SA240 Type 409L has excellent weldability for a ferritic stainless steel. The combination of very low carbon and titanium stabilization minimizes the risk of intergranular corrosion and reduces sensitivity to weld cracking.
Low heat input is still recommended to control grain growth in the heat-affected zone. Matching or suitable ferritic/austenitic filler metals can be used. It is widely welded using resistance, MIG, TIG and laser welding processes in automotive production.
Heat Treatment
Type 409L is a ferritic stainless steel and cannot be hardened by quenching and tempering.
Annealing
- Temperature: typically 750 – 850°C
- Cooling: Air cool
Annealing is used to relieve stresses after cold working or welding and to restore ductility. Time at temperature should be controlled to avoid excessive grain growth.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | SA240 409L 2B – most common for automotive exhaust systems |
| No.1 | Hot-rolled, annealed and pickled | SA240 409L No.1 – industrial plate |
| Special | Bright or custom finishes | SA240 409L Special – on request |
SHH STEEL regularly supplies ASME SA240 409L in 2B finish (especially in coil form) and No.1 finish for plate products.
Tolerances
Dimensional tolerances for ASME SA240 409L Stainless Steel Plate conform to ASME SA240 and the general requirements of ASTM A480.
Typical available size range for SA240 409L plate/sheet/coil:
- Thickness: 0.4 mm – 6.0 mm (thicker plates available on request)
- Width: up to 1500 mm (wider on request)
- Form: Coil or cut-to-length plate
Thickness, width and flatness tolerances are controlled within standard limits. Tighter tolerances for SA240 409L can be arranged for specific automotive or project needs. SHH STEEL provides precise dimensional control for both coil and plate products.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| SA240 Type 409L | ASME SA240 | — |
| A240 Type 409L | ASTM A240 | Essentially identical |
| UNS S40903 | — | Unified Numbering System |
| 1.4512 (related low-C) | EN 10088-2 | Closest European grade |
| SUS409L | JIS G4305 | Japanese equivalent |
| Related low-carbon 409 | GB/T | Chinese approximate equivalents |
Related grades frequently evaluated with ASME SA240 409L include astm a240 type 409 stainless steel sheet plate, astm a240 type 439 stainless steel sheet plate, astm a240 type 441 stainless steel sheet plate, and astm a240 type 430 stainless steel sheet plate.
Applications
ASME SA240 Type 409L is primarily used in automotive exhaust systems where improved weldability and corrosion performance are required. Typical applications of SA240 409L include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Automotive Exhaust | SA240 409L mufflers, exhaust pipes, catalytic converter shells, resonators |
| Heat Exchangers | SA240 409L heat exchanger components in mild high-temperature service |
| Furnace & Heat Treatment | SA240 409L furnace parts and heat-resistant components |
| Agricultural & Construction Equipment | SA240 409L exhaust and heat-related parts |
| General Fabrication | SA240 409L formed and welded high-temperature components |
| Industrial Exhaust Systems | SA240 409L ducting and exhaust components |
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 409L 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)
- Coil and plate supply with flexible dimensions
- Surface finishes including SA240 409L 2B and SA240 409L No.1
- Technical support for automotive exhaust and high-temperature applications
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of SA240 409L over SA240 409?Type 409L has much lower carbon content (≤ 0.03%), providing significantly better weldability and superior resistance to intergranular corrosion after welding. SHH STEEL recommends 409L for more critical welded exhaust systems or when longer service life is required.
- Is ASME SA240 409L magnetic?Yes, Type 409L is magnetic in all conditions. SHH STEEL supplies material that meets this characteristic.
- Can SA240 409L be hardened by heat treatment?No. As a ferritic stainless steel, it cannot be hardened by quenching and tempering. SHH STEEL supplies material in the annealed condition as standard.
- What is the density of SA240 Type 409L?Approximately 7.75 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified ASME SA240 / ASTM A240 Type 409L?Yes, SHH STEEL commonly supplies dual-certified ASME SA240 / ASTM A240 Type 409L material.
Conclusion
ASME SA240 409L Stainless Steel Plate (SA240 Type 409L) is a low-carbon titanium-stabilized ferritic stainless steel that offers improved weldability and better resistance to intergranular corrosion compared with standard Type 409, while retaining excellent high-temperature oxidation resistance and outstanding economy. It is the preferred material for higher-quality automotive exhaust systems and related high-temperature applications.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASME SA240 Type 409L plate and coil with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, coil or plate options, surface finishes (including SA240 409L 2B and SA240 409L No.1), or a competitive quotation.
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