309
Data verified309 is a high-chromium, high-nickel austenitic grade developed for elevated-temperature oxidation resistance. It also serves as a buffer or cladding layer when joining stainless to carbon steel.
Chemical composition
| Element | Content (%) |
|---|---|
| C | ≤0.20 |
| Si | ≤1.00 |
| Mn | ≤2.00 |
| P | ≤0.045 |
| S | ≤0.030 |
| Cr | 22.00–24.00 |
| Ni | 12.00–15.00 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Delivery condition | Annealed |
| Hardness | ≤217 HB (annealed) |
| Tensile strength | 515–690 MPa |
| Density | 7.90 g/cm³ |
| Max scaling temperature | ~980 °C continuous |
Heat treatment
Solution anneal 1040–1120 °C, rapid cool.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.4828 |
| aisi | 309 |
| jis | SUS309 |
| gb | 12Cr23Ni13 |
Compare side by side: 309 vs 309S · 309 vs 310
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Furnace parts, heat-treating fixtures, radiant tubes, dissimilar-metal transition joints, exhaust manifolds.
Processing: Weldable; its high alloy content makes it a standard filler choice for stainless-to-carbon-steel joints. Machining as other austenitics.
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Ask for a quotationVisit NasteelSource: ASTM A240 / EN 10088 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.