SUH409L vs. SUS409L Stainless Steel Coil
Jun 09, 2026
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SUH409L vs. SUS409L Stainless Steel Coil
SUS409L: "SUS" stands for "Stainless Steel for Steel Applications". It conforms to JIS G4305 standard (cold-rolled stainless steel sheet/strip) and is a general classification for stainless steel used in standard structural applications, plates, sheets, and pipes.
SUH409L: "SUH" stands for "Heat-resistant Stainless Steel for Steel Applications". It conforms to JIS G4311 standard (Heat-resistant steel bars and wires) or relevant heat-resistant standards. Its main characteristic is its performance at high temperatures.
What is SUS409L Stainless Steel Coil?
SUS409L stainless steel coil is a low-carbon, titanium-stabilized ferritic stainless steel that conforms to Japanese sheet and strip standards (JIS G 4305). It is supplied in hot-rolled or cold-rolled coil form (typical thickness of cold-rolled coil: 0.3–6 mm, maximum thickness of hot-rolled coil: 120 mm); widths are typically 600–2000 mm. It is primarily used in automotive exhaust systems and other heat- and corrosion-resistant applications.
What is SUH409L 2D Stainless Steel Coil?
SUH409L 2D stainless steel coil is a cold-rolled ferritic stainless steel coil conforming to Japanese JIS standards. It is produced by cold rolling with blunt rolls, followed by annealing and tempering. The surface is a matte silver-gray, a common surface finish for subsequent processing (such as polishing and stretching). It can be used in long-term corrosion-resistant environments ranging from -20℃ to 650℃, exhibiting good oxidation resistance and weldability, and boasting advantages such as low cost and environmental friendliness (recycling rate up to 98%). Currently, it is mainly used in the manufacture of automotive exhaust system components, such as exhaust manifolds, mufflers, and three-way catalytic converters.
SUH409L vs. SUS409L：Key differences
| Feature | SUS409L (Stainless Steel) | SUH409L (Heat-Resisting Steel) |
| Standard | JIS G4305 / G4304 | JIS G4311 / G4312 |
| Microstructure | Ferritic | Ferritic |
| Carbon (C) |
≤ 0.030% |
≤ 0.030% |
| Chromium (Cr) | 10.50% – 11.70% | 10.50% – 11.70% |
| Titanium (Ti) |
6×C to 0.75% |
6×C to 0.75% |
| Manganese (Mn) |
≤ 1.00% |
≤ 1.00% |
| Silicon (Si) |
≤ 1.00% |
≤ 1.00% |
| Yield Strength |
≥ 175 MPa |
≥ 175 MPa |
| Tensile Strength |
≥ 360 MPa |
≥ 360 MPa |
| Elongation |
≥ 25% |
≥ 25% |
| Hardness (HV) |
≤ 175 |
≤ 175 |
| Max Service Temp | ~650°C (Continuous) | ~800°C (Intermittent) |
| Typical Applications | Exhaust pipes, mufflers, plates. | Heat exchangers, catalytic converter shells. |
What is the maximum operating temperature of SUH409L?
In continuous operation, the recommended maximum temperature is 600°C - 650°C.
In intermittent operation (such as repeated heating and cooling of the exhaust pipe), the anti-oxidation and peeling temperature can reach 815°C.
If the temperature consistently exceeds 700°C, it is recommended to upgrade to 439 or 441 material.
Which is better, 409L or 430 stainless steel?
430 stainless steel has a higher chromium content (16%-18%), resulting in better corrosion resistance, but it lacks stabilizing elements and is extremely brittle after welding, making it unsuitable for welded parts.
409L stainless steel has a lower chromium content, but due to its titanium content and low carbon content, it has excellent weldability and a low coefficient of thermal expansion, making it more suitable for welding processes and thermal cycling environments (such as automotive exhaust pipes).
What is the difference between 439 and 409 stainless steel?
439 stainless steel is a high-quality titanium-stabilized ferritic stainless steel with a chromium content of 17-18%, offering superior corrosion resistance and oxidation resistance. In contrast, 409 stainless steel is an economical, lower-grade ferritic alloy with a chromium content of 10.5-11.75%, and it is not titanium-stabilized. Its corrosion resistance is average, and its heat resistance is only sufficient to meet the requirements of standard, non-visible exhaust components.
Applications
Automotive: Exhaust manifolds, front pipes, catalytic converter shells, mufflers, and tailpipes.
Industrial: Heat exchanger tubing, furnace liners, and agricultural equipment spreaders.
Energy: Silencers for power generators and biomass boiler components.
Can SUS409L and SUH409L be used interchangeably when purchasing?
Generally, they are interchangeable. GNEE stainless steel's 409L Material Certificate (MTC) will meet the requirements of both SUS409L and SUH409L. If your application is an automotive exhaust system, both can usually be used. However, if the design drawings specify a "heat-resistant steel" grade, using SUH409L is more compliant.
Cold Rolled SUH409L Stainless Steel Coil Specification
| Item | Specification |
|---|---|
| Product Name | Cold Rolled SUH409L Stainless Steel Coil |
| Material Grade | SUH409L (JIS Standard) |
| Equivalent Grades | ASTM 409L (UNS S40903), EN 1.4512 (X2CrTi12) |
| Microstructure | Ferritic |
| Applicable Standards | JIS G4311 / JIS G4312 |
| Cold Rolled Thickness Range | 0.3mm – 3.0mm |
| Width Range | 1000mm, 1219mm, 1250mm, 1500mm (Slit Edge Available) |
| Coil Inner Diameter (ID) | 508mm or 610mm |
| Surface Finish | 2D (Dull/Matte), 2B (Bright), No.4 |
| Thickness Tolerance | In accordance with JIS G4305 Standard (Precision Tighter Tolerance Available) |
Below is the Material Certificate (MTC) for our 409L stainless steel coils exported to Europe. This product conforms to EN 10204 3.1 standard. Please review!
Packaging must comply with standard maritime regulations: the inner layer must be coated with vapor phase rust inhibitor (VCI) to prevent moisture from causing rust spots on the two-dimensional matte surface. The outer layer must be equipped with metal corner protectors and a steel shell to prevent edge damage from affecting subsequent deep drawing processes. The coils must be securely bundled using fumigated wooden pallets or iron pallets bearing the IPPC mark to ensure the safety of the goods and batch traceability throughout the transportation process.
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