What is the difference between 309 and 309S stainless steel pipe?
Leave a message
What are the equivalent grades of 309 and 309S?
309 → EN 1.4828 / X15CrNiSi20-12
309S → EN 1.4833 / X12CrNi23-13 / UNS S30908
What is the main difference between 309 and 309S stainless steel pipe?
The main difference is carbon content. 309 has up to 0.20% carbon, while 309S is a low-carbon version with ≤0.08%, which improves weldability and resistance to intergranular corrosion.
| Property | 309 Stainless Steel Pipe | 309S Stainless Steel Pipe |
|---|---|---|
| Carbon Content (C) | ≤ 0.20% | ≤ 0.08% (low-carbon variant) |
| Intergranular Corrosion | Higher risk (especially after welding) | Lower risk due to reduced carbon |
| Weldability | Moderate | Better, less carbide precipitation |
| Heat Resistance | Excellent | Excellent |
| Oxidation Resistance | Up to ~1000–1050°C | Up to ~1000–1050°C |
| Typical Standards | ASTM A312, A213 | ASTM A312, A213 |
| Other Names | EN 1.4828 / X15CrNiSi20-12 | EN 1.4833 / X12CrNi23-13 |
Do 309 and 309S have the same temperature resistance?
Yes, both offer excellent oxidation resistance up to ~1000–1050°C. However, for applications requiring extensive welding, 309S is preferred.
What are the typical uses of 309 and 309S pipes?
Common in furnace tubes, heat exchangers, chemical piping, and high-temperature exhaust systems.
Are 309 and 309S stainless steel pipe interchangeable?
In many cases, yes. But if welding is involved or the system runs cyclically at high temperatures, 309S is safer due to lower carbon and better corrosion performance.
Which is more expensive, 309 or 309S stianless seamless pipe?
309S is typically slightly more expensive due to additional refining for low carbon content, but offers better performance in welded systems.
GNEE Supply Range
We offer 309 and 309S stainless steel pipes in:
Sizes: OD 1/2"–24", thickness SCH 10–SCH 160
Process: Seamless & ERW
Surface: Annealed, pickled, polished (Ra ≤ 0.8 μm)
Standards: ASTM A312 / A213 / EN 1.4833 / ISO
Certification: EN 10204 3.1/3.2, PED, ASME
If you're planning for high-temperature fluid systems, oxidizing gas transport, or thermal processing lines, choosing the right grade ensures longer service life and reduced maintenance.
👉 Contact our technical team today to get a quote, datasheet, or material recommendation for your project!
