Grade 347 Stainless Steel – Niobium-Stabilized High-Performance Alloy

Description

Grade 347 is a niobium-stabilized austenitic stainless steel engineered to deliver exceptional intergranular corrosion resistance and high-temperature stability. With 17.0-19.0% chromium and 9.0-13.0% nickel, it offers corrosion resistance comparable to 304 series, while the 0.80-1.20% niobium addition forms highly stable carbides-providing superior resistance to sensitization compared to titanium-stabilized grades. Its non-magnetic structure and excellent mechanical properties make it suitable for both low and elevated temperature service. Unlike standard 304-based alloys, 347 delivers enhanced creep resistance and long-term thermal stability, making it the preferred choice for critical applications in aerospace and nuclear industries.

Chemical Composition (wt%)

C ≤ 0.08, Cr: 17.00-19.00, Ni: 9.00-13.00, Nb+Ta: 0.80-1.20, Mn ≤ 2.00, Si ≤ 1.00, P ≤ 0.045, S ≤ 0.030

Mechanical Properties

Tensile Strength ≥ 515 MPa, Yield Strength ≥ 205 MPa, Elongation ≥ 40%, Hardness ≤ 201 HB

Advantages

Niobium-stabilized for superior intergranular corrosion resistance; excellent high-temperature stability; better creep resistance than titanium-stabilized grades; non-magnetic; suitable for critical applications.

Applications

Aerospace components, nuclear reactor parts, petrochemical processing equipment, heat exchangers, and high-temperature welded structures.

Equivalent Grades

UNS S34700, EN 1.4550, GB 06Cr18Ni11Nb, SUS347

Stainless Steel Suppliers

If you have project requirements for stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com

 

Testing and Documentation: Factory test certificate, EN 10204 3.1, chemical report, mechanical report, destructive testing report, non-destructive testing report, PMI test report, visual inspection report, third-party inspection report, NABL certified laboratory report.
Packaging: Wooden crate packaging, bubble wrap packaging, steel strapping, or packaging according to customer requirements.