310S Stainless Steel Seamless Pipe & Tube
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1.4845 – 25/20 austenitic heat-resistant steel
1.4845 (AISI 310S), X8CrNi25-21, contains about 25% chromium and 20% nickel. This high chromium content forms a dense oxide layer in hot gases that protects the metal against scaling in air up to approx. 1,050 °C (1,920 °F), while nickel stabilizes the austenite, so the material stays ductile and withstands thermal cycling. The “S” stands for lower carbon than 310, which makes welding easier. Unlike 1.4841 (314), 310S has less silicon. For an overview of steels for high-temperature service, see the article Heat-resistant steel: grades and applications.
Chemical composition of 1.4845 / 310S
| Grade | C | Si | Cr | Ni |
|---|---|---|---|---|
| 1.4845 / 310S | ≤ 0.10 | ≤ 1.50 | 24.0–26.0 | 19.0–22.0 |
| 1.4841 / 314 (for comparison) | ≤ 0.20 | 1.50–2.50 | 24.0–26.0 | 19.0–22.0 |
Composition in wt. % per EN 10095. Equivalents: 1.4845 = X8CrNi25-21 = AISI 310S = UNS S31008; pipe and tube per ASTM A312 / A213 – TP310S.
Sizes in stock
The category lists 340 items: pipe and tube from 13.5 to 305 mm OD with walls from 2 to 20 mm, including 42.4 × 5, 60.3 × 3.2, 101.6 × 8, 168.3 × 6.3, 219.1 × 10 and 273 × 20 mm, in lengths from 10 cm to 3 m. We cut any tube to length. In parts exposed to high heat, a heavier wall provides a scaling allowance and limits sagging under the part’s own weight.
Applications and limitations
310S pipe and tube is used for radiant tubes, muffles and retorts in heat-treating furnaces, thermocouple protection tubes, burner and nozzle components, hot-air ducts and plant parts in the cement, ceramics and petrochemical industries. Long service at approx. 600–900 °C (1,110–1,650 °F) can lead to sigma phase, which reduces ductility once the part cools. In sulfur-bearing atmospheres, nickel-free ferritic grades perform better. The difference between heat-resistant and creep-resistant steel is explained in the article heat-resistant vs. creep-resistant steel.
Other grades for high temperatures
1.4841 / 314 and ferritic grades are in the heat-resistant pipe & tube (1.4841 / 314) subcategory. Up to approx. 800 °C (1,470 °F), 321 / 1.4541 and 321H pipe & tube is often sufficient. In the same grade we also offer 310S / 1.4845 round bar. Other pipe and tube is in the Seamless tubes and hollow bars category.