Description
Global Standards & Grades
| Region |
Standard |
Grade |
| USA |
ASTM A213 |
UNS S30900 |
| Europe |
EN 1.4828 |
X15CrNiSi20-12 |
| Japan |
JIS SUS309S |
- |
| China |
GB/T 20878 |
06Cr23Ni13 |
Chemical Composition (Weight %)
| Cr |
Ni |
C |
Mn |
Si |
P |
S |
Fe |
| 22–24% |
12–15% |
≤0.20% |
≤2.0% |
1.0–2.5% |
≤0.045% |
≤0.03% |
Balance |
Key Differentiators
Thermal Mastery:
Retains strength at 1.000°C (1.832°F) with oxidation resistance 3x better than 304.
Resists carburization in hydrocarbon-rich atmospheres (e.g., ethylene crackers).
Cyclic Stability:
Low thermal expansion coefficient (16.0 µm/m°C) minimizes warping during rapid heating/cooling.
Corrosion Defense:
PREN (Pitting Resistance): 22–24—superior to 316L in acidic flue gas condensates.
Fabrication Edge:
Pre-annealed at 1.050°C to prevent sigma phase formation during welding.
Mechanical Properties
| Condition |
Tensile Strength |
Yield Strength |
Elongation |
Creep Limit (1.000h) |
| Room Temp |
620–840 MPa |
310 MPa (min) |
40% (min) |
- |
| 900°C |
65 MPa |
45 MPa |
25% |
28 MPa |
Industry Applications
Heat Treatment: Radiant tubes, annealing furnace muffles, quenching baskets.
Energy: Biomass boiler superheaters, waste-to-energy incinerator ducts.
Chemicals: Ethylene cracking coils, syngas reformer tubes.
Automotive: Turbocharger housings, exhaust gas recirculation (EGR) systems.
Glass: Molten glass conveyance tubes, lehr rollers.
Fabrication Guidelines
Welding:
Use ER309/ER309L filler with 98% Ar + 2% N₂ shielding for sulfidation resistance.
Interpass temperature ≤150°C to avoid hot cracking.
Forming:
Hot-forming recommended above 1.100°C; cold-forming requires intermediate annealing.
Post-Treatment:
Solution anneal at 1.040–1.120°C followed by water quenching for carbide dissolution.
Frequently Asked Questions
Q1: How does 309 differ from 310 stainless tubes?
A1: 309 has lower nickel (13% vs. 19–22%) but higher silicon for better scaling resistance below 1.050°C. 310 excels in continuous extreme heat.
Q2: Is it suitable for cryogenic temperatures?
A2: No—use 304L/316L below -150°C. 309’s ductility drops sharply below -50°C.
Q3: What surface finishes optimize heat reflection?
A3: Electropolished (Ra ≤0.4 µm) or ceramic-coated (Al₂O₃) surfaces reduce radiant heat absorption.
Q4: Can it handle reducing atmospheres (e.g., H₂-rich)?
A4: Limited performance. Consider alloy 800H/HT for hydrogen embrittlement resistance.
Q5: What’s the maximum allowable sulfur content in service?
A5: ≤0.02% in fuel gases to prevent catastrophic sulfidation attack.
