Stainless Steel 409 (UNS S41100)
Stainless Steel 409 is a titanium-stabilized ferritic stainless steel. Though it contains a lower chromium content than many other stainless grades, it offers excellent resistance to atmospheric corrosion and high-temperature oxidation. It was originally designed for the automotive exhaust industry, but its unique balance of economy and durability has made it a favorite for any application where carbon steel would succumb to rust, but high-nickel alloys are not cost-justified.
At Aries Alloys, we supply Stainless Steel 409 to manufacturers of industrial heating systems and automotive components. It is the "workhorse" grade for environments that require the metal to withstand thermal cycling and corrosive exhaust gases without structural failure.
Key Performance Benefits
- Superior Thermal Stability: Outperforms carbon steel in high-heat applications, maintaining its integrity during repeated heating and cooling cycles.
- Titanium Stabilization: The addition of titanium prevents hardening during welding and improves the alloy’s resistance to intergranular corrosion.
- Oxidation Resistance: Provides reliable protection against scaling in temperatures up to 1475° F (800° C) in continuous service.
- Exceptional Formability: Highly ductile, allowing it to be easily bent, stretched, and drawn into complex shapes like mufflers and manifolds.
- Cost-Effective Durability: Offers the longevity of stainless steel at a price point closer to coated carbon steels.
Technical Profile & Composition
The Ferritic Advantage:
As a ferritic steel, Type 409 has a body-centered cubic crystal structure, making it magnetic in all conditions. Its low carbon and nitrogen content, paired with the stabilizing titanium, ensures that the material remains easy to weld and form without becoming brittle.
Mechanical & Physical Data:
- Density: 7.80 g/cm^3
- Magnetic Property: Strongly magnetic.
- Thermal Conductivity: Better than austenitic (300-series) steels, allowing for more efficient heat transfer in furnace applications.
- Corrosion Note: While 409 is highly resistant to rust, it may develop a light surface discoloration (tea staining) over time; this is purely cosmetic and does not affect the structural life of the material.
Primary Industrial Use Cases
Aries Alloys is a key supplier of Stainless Steel 409 for "utility-grade" applications:
- Automotive Systems: Catalytic converters, exhaust pipes, mufflers, and tailpipes.
- Industrial Heating: Furnace liners, heat exchanger tubing, and burner components.
- Agricultural Equipment: Spreader components and dry fertilizer bins where carbon steel would corrode.
- Power Generation: Silencers and structural supports for gas turbines.
- Home Infrastructure: Woodstove liners and outdoor furnace components.
Product Availability at Aries Alloys
We stock and supply Stainless Steel 409 in several formats complying with ASTM A240:
- Coils & Sheets: Ideal for high-volume stamping and automotive component manufacturing.
- Welded Tubes: High-durability tubing for exhaust systems and heat transfer lines.
- Plates: Durable flat products for industrial furnace structures.
- Custom Slit Strips: Tailored widths for specialized roll-forming applications.