Description
Grade 309 / 309S are austenitic chromium-nickel stainless steels, which are often used for high temperature applications. Due to their high chromium and nickel content, Grade 309 / 309S pipes are highly corrosion resistant, and have outstanding resistance to oxidation. Also, they exhibit excellent heat resistance while providing good strength at ambient or elevated temperatures. However, the only significant difference between 309 and 309S is the carbon content. Grade 309S stainless steel pipes have a much less carbon composition, which minimizes carbide precipitation, and improves weldability.
309 / 309S Stainless Steel Pipe Properties
The following properties of 309 / 309S stainless steel pipes make them suitable for specific applications:
High Temperature:
Superior heat resisting austenitic stainless steel Good for continuous exposure to 2000 degree F Intermittent service to 1800 degree F.
Corrosion Resistance:
- Excellent corrosion and oxidation resistance
- More resistant to marine atmospheres than grade 304
- High resistance to sulfite liquors
- Generally considered heat resistant grade
- Destructive scaling temperature is approximately 2000 °F
- Good scaling resistance with regard to continuous and intermittent service
- High temperature corrosion resistance in most in-service conditions
The grade does not perform as well as grade 600 or 800 steel in reducing, nitriding or carburizing atmospheres. However, it does outperform most heat resistant stainless steels in these conditions.
Heat Treatment:
- They cannot be hardened through heat treatment because they consist solely of austenite at room temperature
- Higher tensile and yield strengths can be obtained through cold working
Fabrication:
- Can be roll formed, stamped, and drawn readily
- In process annealing is often required to reduce hardness and increase ductility
Weldability:
- The austenitic class of stainless steels is generally considered to be weldable by common fusion and resistance techniques
- Generally, they are considered to have weldability equivalent to common alloys of the austenitic class 304 and 304L
Applications:
309 / 309S stainless steel pipes and tubes are used exclusively for their excellent oxidation resistance, and strength at high temperatures. Additionally, they offer good resistance to creep deformation and extreme environment. Some examples include, but are not limited to:
- Heating elements
- Aircraft and jet engine parts
- Heat exchangers
- Carburizing annealing products
- Sulfite liquor handling equipment
- Kiln liners
- Boiler baffles
- Refinery and chemical processing equipment
- Auto exhaust parts
CHEMICAL PROPERTIES:
| Typical Chemical Composition % (max values, unless noted) | ||||||||
| Grade | C | Mn | Si | P | S | Cr | Ni | Fe |
| 309 | max: 0.4 min: 0.8 | 2.0 max | 0.75 max | 0.045 max | 0.03 max | min: 22.0 max: 24.0 | min: 12.0max: 15.0 | Balance |
| 309H | min: 0.04 max: 0.08 | 2.0 max | 0.75 max | 0.045 max | 0.03 max | min: 22.0 max: 24.0 | min: 12.0max: 15.0 | Balance |
MECHANICAL PROPERTIES:
| Typical Room Temperature Mechanical Properties | ||||
| Grade | Tensile StrengthKSI (MPA) | Yield Strength 0.2% KSI offset KSI (MPA) | Elongation (% in 2ʺ(50.8 mm) | Hardness (Brinell) MAX |
| 309/H | 40 | 30 | 40 | 217 |
Fenton, Missouri based Arch City Steel & Alloy is a leading stainless steel pipe distributor in the country. Inquiry for the product to source pipes that meet your specifications, dimensions and sizes.
