347 is a niobium-stabilized austenitic steel similar to 321 but with better high-temperature strength. It prevents intergranular corrosion after exposure to high temperatures.
Key Properties
Stabilization: Niobium prevents chromium carbide precipitation.
High Temp: Good mechanical properties up to 800°C.
Weldability: Excellent for heavy gauge welding without post-weld annealing.
Ductility: Good formability for complex high-temp parts.
Common Applications
Aerospace: Exhaust manifolds and firewalls.
Refining: Catalytic cracking equipment and expansion joints.
Boilers: Superheater tubes and high-temp piping.
Automotive: Thermal oxidizers and exhaust components.