SUS321 Stainless Steel: Thermal Stability Weldable Grade

Key Characteristics

Thermal Stability: Titanium addition prevents chromium carbide formation at grain boundaries during high-temp exposure, maintaining corrosion resistance.

Weldability: Excellent weldability by standard methods; post-weld annealing isn't usually required.

Corrosion Resistance: Similar to Grade 304 but better in high-temp service; resists intergranular corrosion after welding.

High-Temp Strength: Retains good strength and toughness up to around 900°C (1650°F).

Cryogenic Toughness: Maintains good toughness at low temperatures.

Applications

Aerospace industry (jet engine parts).

Chemical processing equipment.

Furnace parts and heat exchangers.

Automotive exhaust systems.

Considerations

Chloride Environments: Vulnerable to pitting/crevice corrosion in warm chloride solutions; Grade 316 is better for this.

Welding Consumable: Grade 347 (Niobium-stabilized) is generally preferred as the filler metal for welding 321 because titanium doesn't transfer well across the arc.