Description
Chemical Composition and Mechanical Properties of SUS347 Stainless Steel
SUS347 is a niobium (columbium)-stabilized austenitic stainless steel with the following composition and properties:
Chemical Composition:
| Element | Percentage |
|---|---|
| Carbon (C) | ≤0.08% |
| Chromium (Cr) | 17.0-19.0% |
| Nickel (Ni) | 9.0-13.0% |
| Manganese (Mn) | ≤2.00% |
| Silicon (Si) | ≤0.75% |
| Phosphorus (P) | ≤0.045% |
| Sulfur (S) | ≤0.030% |
| Niobium (Nb) | 10xC min/1.00 max |
Mechanical Properties:
| Property | Value |
|---|---|
| Yield Strength (min) | 206 MPa |
| Tensile Strength (min) | 520 MPa |
| Elongation (min) | 40% |
| Hardness (max) | 92 HRB |
Applications and Industries Using SUS347 Stainless Steel
SUS347 is ideal for high-temperature and corrosive environments due to its excellent mechanical properties and resistance to intergranular corrosion:
- Aerospace Industry: Used in engine parts, gas turbines, and exhaust systems.
- Petrochemical Industry: Employed in cracking units, refining devices, and heat exchangers.
- Power Generation: Suitable for high-pressure steam environments such as boilers and nuclear power plants.
- Food Processing Equipment: Applied in cookers, drying equipment, and other high-temperature food processing machinery.
- Chemical Processing: Used in reactors, storage tanks, and piping systems.
- Marine Applications: Ideal for components exposed to saltwater environments.
Manufacturing Process of SUS347 Stainless Steel
The manufacturing process involves several steps:
- Melting Raw Materials: Raw materials like iron ore, chromium, nickel, and niobium are melted in an electric arc furnace.
- Refining: The molten metal is refined using Argon Oxygen Decarburization (AOD) or Vacuum Oxygen Decarburization (VOD).
- Casting: The refined molten steel is cast into slabs or billets.
- Hot Rolling: The slabs are hot-rolled into sheets or plates.
- Cold Rolling: Further rolling at room temperature achieves the final dimensions.
- Heat Treatment: Solution annealing at 1050-1150°C followed by rapid cooling ensures optimal mechanical properties.
Comparison of SUS347 with Other Stainless Steel Grades
| Grade | Stabilizing Element(s) | Corrosion Resistance | High-Temperature Performance |
|---|---|---|---|
| SUS304 | None | Good | Moderate |
| SUS321 | Titanium | Very Good | Very Good |
| SUS347 | Niobium/Columbium | Excellent | Excellent |
SUS347 offers superior resistance to intergranular corrosion compared to SUS304 and better high-temperature strength than both SUS304 and SUS321.
Corrosion Resistance and Heat Treatment of SUS347
Corrosion Resistance:
- Resistant to intergranular corrosion due to niobium stabilization.
- Performs well in environments containing acids, alkalis, and salts.
- Suitable for applications with temperatures ranging from 800°F to 1500°F (427°C to 815°C).
Heat Treatment:
- Solution annealing: Heat to 1050-1150°C followed by rapid cooling.
- Does not require post-weld annealing due to its stabilized structure.
Advantages of Using SUS347 in High-Temperature Applications
- Excellent resistance to oxidation up to 1500°F (815°C).
- High creep strength in elevated temperature environments.
- Superior resistance to carbide precipitation during welding or prolonged heat exposure.
At HL Steel Company, we supply high-quality SUS347 stainless steel products for various industries, ensuring durability, corrosion resistance, and performance in demanding applications such as aerospace, petrochemical processing, and power generation systems.





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