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309S Austenitic Heat-Resistant Stainless Steel
309S is a high-chromium-nickel austenitic stainless steel engineered for elevated-temperature applications. Key characteristics include:
- Exceptional oxidation resistance: Sustained service up to 1100°C (2012°F), short-term exposure to 1150°C (2102°F).
- Superior thermal fatigue resistance: Performs under repeated thermal cycling.
- Excellent manufacturability: Compatible with welding, forming, and machining processes.
- Low-carbon design (S-grade): Carbon content ≤0.08% minimizes carbide precipitation and intergranular corrosion risks.
Technical Parameters (Chemical Composition, wt%)
| Element | Standard Range | Element | Standard Range |
|---|---|---|---|
| C | ≤0.08 | Cr | 22.0–24.0 |
| Si | ≤1.00 | Ni | 12.0–15.0 |
| Mn | ≤2.00 | Mo | ≤0.75 |
| P | ≤0.045 | N | ≤0.10 |
| S | ≤0.030 | Fe | Balance |
| Complies with ASTM A240/A480. Trace elements not listed are controlled per industry standards. | |||
Surface Finishes
- Standard Finishes:
- 2B (Cold-rolled bright annealed), No.1 (Hot-rolled annealed & pickled), BA (Bright annealed)
- Bead blasting (Sa 2.5), Brushed (Directional/Random)
- Enhanced Treatments:
- Electropolishing (improved corrosion resistance)
- Passivation (strengthened oxide layer)
Why Choose Us ?
- Integrated ManufacturingFull-process control (Smelting → Hot Rolling → Cold Rolling → Finishing).
- Certifications: ISO 9001, SGS, Mill Test Certificates (MTC), export compliance documentation.
- Customization:Non-standard sizes (0.1–50mm thickness), tailored surface finishes.
- Global Logistics:30-day delivery guarantee, FOB/CIF terms supported.
Applications & Industries
Thermal Processing
Furnace rolls, radiant tubes, burner liners
Food Processing
Baking conveyors, high-temperature ovens
Power Generation
Boiler parts, flue gas systems
Petrochemical
Cracking furnace tubes, heat exchangers
Automotive
Exhaust systems, turbo housing components
Workshop & Packaging (Illustrative)
- Production Workshop:
- Image caption: CNC plasma cutting + automated welding line
- Packaging Standards:
- PE-coated moisture-proof wood crates
- Edge-protected coil bundling
- Custom labeling (Material grade/Batch No./Anti-corrosion warnings)
Frequently Asked Questions
Q1: How does 309S differ from 310S?
A: 309S has lower Cr/Ni (310S: Cr 24-26%, Ni 19-22%), making it cost-effective for ≤1100°C applications. 310S offers superior oxidation resistance (up to 1200°C).
Q2: Are special welding consumables required?
A: Use 309L-grade fillers (e.g., ER309LSi) to prevent carbide precipitation at weld zones.
Q3: Can 309S replace 316L in corrosive environments?
A: Not recommended. 316L contains molybdenum (2-3%) for chloride resistance, while 309S excels in high-temperature oxidation resistance.
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