Key Feature

The Stabilized Ferritic Stainless for Weld Fabrication. Aluminum addition prevents martensite formation in welds, providing consistent properties in as-welded condition without post-weld heat treatment.

Specifically designed for welded assemblies where 430 would harden excessively in heat-affected zones.

Common Designations

UNS S40500
AISI 405
EN 1.4002, X6CrAl13
JIS SUS405
BS 405S17

One of the few ferritic stainless steels specifically engineered for weldability.

Chemical Composition (Typical wt.%)

C: ≤ 0.08
Cr: 11.5 - 14.5
Al: 0.10 - 0.30Mn: ≤ 1.00
Si: ≤ 1.00
P: ≤ 0.040
S: ≤ 0.030

Aluminum content is critical for ferrite stabilization and preventing martensite formation.

Mechanical Properties (Annealed)

Tensile Strength (Rm): ≥ 415 - 550 MPa
Yield Strength (Rp0.2): ≥ 205 - 275 MPa
Elongation (A): ≥ 20-25%
Hardness (HB): ≤ 183

Moderate strength with good ductility; comparable to 430 in annealed condition.

Weld Zone Properties

HAZ Hardness: Typically ≤ 250 HB
No Martensite FormationConsistent Properties across weldment
No Post-Weld Heat Treatment required

Aluminum promotes ferrite formation, preventing hard, brittle zones in welds.

Physical Properties

Density: 7.70 g/cm³
Melting Range: 1480 - 1530 °C
Thermal Expansion: 10.8 × 10⁻⁶/K (20-400°C)
Thermal Conductivity: 25.0 W/m·K (100°C)
Strongly magnetic

Typical ferritic stainless steel properties with lower thermal expansion than austenitic grades.

Heat Treatment

Annealing: 760-830°C, air or slow cool
Not hardenable by heat treatmentStress Relief: 650-760°C
Maximum Service Temperature: 650-700°C

Can only be strengthened by cold working; limited high-temperature capability due to 475°C embrittlement risk.

Corrosion Resistance

Good resistance to atmospheric corrosion, nitric acid, organic acids, and fresh water. Similar to 410 but inferior to 304. Not suitable for marine or chloride-rich environments.

Adequate for many industrial applications; not for severe corrosive conditions.

Key Standards (Coil)

ASTM A240 (Plate, Sheet, and Strip)
ASTM A480 (General Requirements)
EN 10088-2
AMS 5507 (Aerospace)
JIS G4305

Widely specified in heat exchanger and welded fabrication applications.

Common Applications (from Coil)

• Heat Exchangers: Tube sheets, baffles, headers
• Furnace Components: Radiant tubes, burner parts, structural supports
• Chemical Processing: Welded tanks, reactors, piping (mild service)
• Power Generation: Boiler parts, feedwater heaters, condenser components
• Automotive: Exhaust system components, manifolds
• Food Processing: Welded equipment frames, supports, structural elements
• Architectural: Welded structural elements, supports, frames

Specifically selected where welding is extensive and consistent weld zone properties are critical.