Key Feature

The Economical Titanium-Stabilized Ferritic Stainless Steel Bar Stock. Lower chromium content and titanium stabilization provide cost-effective corrosion resistance for automotive and moderate temperature bar applications.

The most economical stainless steel bar for automotive exhaust systems and similar applications.

Common Designations

UNS S40900
AISI 409
ASTM A276 (Stainless Steel Bars)
EN 1.4512, X6CrTi12
JIS SUS409
SAE J409

ASTM A276 is the primary specification for general bar applications.

Chemical Composition (Typical wt.%)

C: ≤ 0.08
Cr: 10.5 - 11.7Ti: ≥ 6×C (min 0.15%)Mn: ≤ 1.00
Si: ≤ 1.00
P: ≤ 0.045
S: ≤ 0.030

Lower chromium than 430/304; titanium stabilization prevents sensitization.

Mechanical Properties

Tensile Strength: ≥ 380 MPa
Yield Strength: ≥ 205 MPa
Elongation: ≥ 20%
Hardness: ≤ 183 HB
Machinability: 65% of B1112 steel

Adequate strength for most automotive and industrial bar applications with good machinability.

Physical Properties

Density: 7.70 g/cm³
Melting Range: 1425 - 1510 °C
Thermal Expansion: 10.8 × 10⁻⁶/K (20-400°C)
Thermal Conductivity: 25.0 W/m·K (100°C)
Strongly magnetic

Low thermal expansion similar to carbon steel; beneficial for exhaust systems.

Available Forms

Rounds: 6mm - 150mm diameter
Squares: 6mm - 75mm
Hexagons: 6mm - 50mm
Flats: Various sizes
Wire: For specific applications

Commonly supplied in sizes suitable for automotive and exhaust components.

Surface Conditions

Hot Rolled: Black, scaled surface
Cold Drawn: Bright, smooth finish
Centerless Ground: Precision ground
Polished: For decorative applications
Peeled: Improved surface for machining

Various surface finishes available, though less polished than premium grades.

Corrosion Resistance

Moderate resistance to atmospheric corrosion, exhaust gases, and mild chemicals. Not suitable for marine or severe chemical environments.

Adequate for automotive exhaust and many industrial applications; inferior to 304/430.

Machining Characteristics

• Good machinability for stainless steel
• Better than austenitic grades
• Good chip control• Low tool wear• Surface finish generally good

One of the more machinable stainless steels due to ferritic structure and composition.

Welding Characteristics

Good weldability with proper techniques
No post-weld heat treatment requiredTitanium prevents sensitizationMatching filler metals recommended

Suitable for most welding methods; maintains corrosion resistance in weld zone.

Temperature Limits

Continuous Service: Up to 700°C
Intermittent Service: Up to 815°C
Minimum Service: -30°C
Avoid: 475-900°C (embrittlement)

Suitable for exhaust temperatures typically encountered in automotive applications.

Key Standards

ASTM A276 409: Stainless Steel Bars
ASTM A479 409: Bars for Pressure Vessels
ASTM A484: General Requirements
EN 10088-3: Stainless Steel Bars
JIS G4303: Stainless Steel Bars
SAE J409: Automotive Standards

Specifically referenced in automotive industry standards.

Common Applications

• Automotive Exhaust Components: Exhaust manifolds, catalytic converter housings, muffler parts, tailpipe flanges
• Industrial Exhaust Systems: Chimney liners, exhaust stack components, pollution control parts
• Agricultural Equipment: Structural components, exhaust parts, equipment frames
• Construction: Non-structural supports, ventilation components, architectural trim
• Container Manufacturing: Chemical tank components (mild service), storage container parts
• Furniture: Outdoor furniture frames, structural components, hardware
• Fasteners: Bolts, nuts, screws for moderate corrosion environments

Specifically designed for cost-sensitive bar applications requiring better corrosion resistance than carbon steel.