STS347 – Niobium-Stabilized Austenitic Alloy For Welded High-Temperature Components

Overview

STS347 is a niobium-stabilized austenitic stainless steel, designed to eliminate intergranular corrosion in welded components and high-temperature service. By adding niobium (Nb + Ta: 8×C~1.00%), it forms niobium carbides, which prevent the formation of chromium carbides and maintain the material's corrosion resistance even after exposure to temperatures between 430-900°C. It contains 17.00-19.00% chromium and 9.00-13.00% nickel for general corrosion resistance and a stable austenitic structure, is non-magnetic, and has excellent weldability and formability. It offers better high-temperature strength than STS321 and is suitable for welded structures in high-temperature corrosive environments.

Chemical Composition (wt%)

C ≤ 0.08, Cr: 17.00-19.00, Ni: 9.00-13.00, Nb + Ta: 8×C~1.00, Mn ≤ 2.00, Si ≤ 1.00, P ≤ 0.045, S ≤ 0.030

Typical Mechanical Properties (Annealed Condition)

Tensile Strength (Rm): ≥ 550 MPa; Yield Strength (Rp0.2): ≥ 210 MPa; Elongation (A): ≥ 40%; Brinell Hardness (HB): ≤ 205

Core Advantages

Niobium stabilization prevents intergranular corrosion in welds and high-temperature service; excellent high-temperature creep strength and oxidation resistance; non-magnetic; good weldability and formability; superior toughness compared to titanium-stabilized grades; suitable for welded high-temperature components and corrosive environments.

Applications

Aerospace exhaust manifolds, chemical processing equipment, high-temperature heat exchangers, boiler components, nuclear processing piping, and welded structural parts requiring high-temperature stability and corrosion resistance.

Equivalent Grades

EN 1.4550, UNS S34700, GB 06Cr18Ni11Nb, AISI 347, 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.