- Description
347 stainless steel plate is an austenitic chromium-nickel stainless steel stabilized with niobium (columbium). It is designed to provide excellent resistance to intergranular corrosion, especially in high-temperature environments and after welding. Compared with 304 and 321 stainless steels, 347 offers superior stability in long-term elevated temperature service.
Chemical Composition of 347 Stainless Steel Plate
The key feature of 347 stainless steel is niobium (Nb) stabilization, which prevents chromium carbide precipitation.
| Element | Content (%) |
|---|---|
| Chromium (Cr) | 17.0–19.0 |
| Nickel (Ni) | 9.0–13.0 |
| Niobium (Nb) | ≥ 10 × C (typically 0.8–1.0) |
| Carbon (C) | ≤ 0.08 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.03 |
| Iron (Fe) | Balance |
Mechanical Properties of 347 Stainless Steel
347 stainless steel maintains stable mechanical strength and good toughness under both room and elevated temperatures.
| Property | Typical Value |
|---|---|
| Tensile Strength | 515–750 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 201 HB |
| Density | 7.9 g/cm³ |
Main Performance Features
1. Excellent High-Temperature Resistance
347 stainless steel performs well in continuous service at temperatures up to 870°C, making it suitable for thermal and high-heat industrial systems.
2. Strong Resistance to Intergranular Corrosion
Niobium stabilization prevents carbide precipitation during welding or heat exposure, significantly improving resistance to intergranular corrosion compared with non-stabilized grades like 304.
3. Good Weldability
347 stainless steel can be welded using standard methods without requiring post-weld heat treatment in most applications. It is especially suitable for heavy welded structures.
4. Stable Mechanical Properties
It maintains good strength, ductility, and oxidation resistance in long-term thermal cycling conditions.
Common Applications of 347 Stainless Steel Plate
347 stainless steel plate is widely used in high-temperature and corrosion-resistant welded equipment.
Typical applications include:
- Heat exchangers
- Boiler components
- Furnace parts
- Jet engine exhaust systems
- Chemical processing equipment
- Pressure vessels
- Expansion joints
- High-temperature piping systems
- Petrochemical industry equipment
- Power generation systems
347 Stainless Steel vs 321 Stainless Steel
| Property | 347 Stainless Steel | 321 Stainless Steel |
|---|---|---|
| Stabilizer | Niobium (Nb) | Titanium (Ti) |
| High Temperature Stability | Higher | Good |
| Intergranular Corrosion Resistance | Very strong | Strong |
| Weld Performance | Excellent | Excellent |
| Typical Use | Severe thermal environments | General high-temperature use |
