Chemical Composition and Mechanical Properties of 409 (S40900) Stainless Steel

409 stainless steel is a ferritic, titanium-stabilized grade with the following composition and properties:

Mechanical Properties:

Applications and Industries Using 409 Stainless Steel

409 stainless steel is widely used in:

1. Automotive exhaust systems
2. Catalytic converters
3. Mufflers and tailpipes
4. Farm equipment
5. Heat exchangers
6. Furnace components
7. Structural supports and hangers

Its combination of moderate corrosion resistance and good formability makes it ideal for these applications.

Manufacturing Process and Heat Treatment of 409 Stainless Steel

Manufacturing process:

1. Melting raw materials
2. Refining using AOD or VOD
3. Continuous casting
4. Hot rolling
5. Cold rolling
6. Annealing

Heat treatment:

• Annealing temperature: 750-900°C
• Normalizing: 1750-1850°F (954-1010°C)

409 stainless steel is not hardenable through conventional heat treatment methods.

Corrosion Resistance and Performance Characteristics

409 stainless steel offers:

• Good resistance to atmospheric and exhaust gas corrosion
• Oxidation resistance up to 815°C in intermittent service
• Moderate corrosion resistance in mildly corrosive environments

It forms a light surface rust that inhibits further corrosion but may affect appearance.

Comparison of 409 Stainless Steel with Other Grades

409 offers a cost-effective alternative with moderate corrosion resistance.

Formability and Welding Considerations for 409 Stainless Steel

Formability:

• Good formability through roll forming, stretch bending, and deep drawing
• Does not significantly work harden during mild forming processes

Welding:

• Readily weldable using various methods (GTAW, GMAW, resistance welding)
• Preheating to 150-260°C recommended
• Post-weld annealing at 760-815°C improves ductility
• Automotive exhaust tubing often welded without filler metal

At HL Steel Company, we offer high-quality 409 stainless steel products tailored for various industrial applications, ensuring optimal performance and cost-effectiveness for our customers.