GRADE PROFILE
316Ti stainless steel — 1.4571 / X6CrNiMoTi17-12-2
316Ti is a molybdenum-bearing 316 with titanium added, 0.3 to 0.7%. The titanium ties up carbon and prevents chromium carbide precipitation in the heat-affected zone. It was the answer before low-carbon grades existed — and it remains the right answer above 400 °C, where 316L no longer suffices.
- Austenitic
- PREN 24–26
- Cost index 140
- Welded · Seamless · Heat exchanger
- Ø 10 to 610 mm
When to choose it
On welded equipment running hot that cannot be heat-treated after assembly. Chemicals, process piping, heat exchangers, vessels welded on site. Between 400 and 550 °C, the low carbon of a 316L no longer protects against sensitisation while titanium keeps tying up carbon: that is the only band where 316Ti is objectively superior.
It also earns its place where an older specification names it and the existing plant is in 316Ti. Mixing 316L and 316Ti on one network has no serious metallurgical consequence, but it complicates the certificate trail.
When not to choose it
At ambient or moderate temperature, where 316L does the same job for less and welds just as easily. This is by far the most common case, and replacing a 316L with a 316Ti by reflex is spending with nothing in return.
Where the specification requires strictly low carbon. 316Ti goes to 0.08%: if your specification caps carbon at 0.030%, the grade is out of specification whatever its stabilisation.
In seawater and high chlorides, as with 316L: titanium brings nothing to that fight.
Composition
| Element | % |
|---|---|
| C | ≤ 0.08 |
| Cr | 16.5–18.5 |
| Ni | 10.5–13.5 |
| Mo | 2–2.5 |
| Ti | 0.3–0.7 |
| Mn | ≤ 2 |
| Si | ≤ 1 |
Mechanical properties
We only publish mechanical properties tied to a specific standard and product form — welded tube, seamless tube and bar do not share the same values, and the gap routinely exceeds 30%. The figures that apply to your specification appear on the material certificate; ask us at enquiry stage.
Designations and standards
| Reference | Designation |
|---|---|
| EN (numeric) | 1.4571 |
| EN (symbolic) | X6CrNiMoTi17-12-2 |
| ASTM / AISI | 316Ti |
| UNS | S31635 |
| JIS | SUS316Ti |
| AFNOR | — |
Tube product standards :
- EN 10216-5
- EN 10217-7
- ASTM A312
Availability
Welded, seamless and heat exchanger tube, Ø 10 to 610 mm, plus fittings, flanges and bar. Partner stock or mill depending on the size and quantity. EN 10204 3.1 material certificates supplied with the goods.
Related grades
- 316L (1.4404) — the default below 400 °C, cheaper.
- 321 (1.4541) — the same titanium stabilisation without molybdenum, for high temperature away from chlorides.
- 347H (S34709) — niobium stabilisation where creep, not sensitisation, is the governing factor.
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Frequently asked questions
- 316Ti or 316L?
- Below 400 °C, 316L — cheaper and lower in carbon. Between 400 and 550 °C in continuous service, 316Ti, whose stabilisation still works where low carbon no longer protects. Above that, look at the H grades.
- Does titanium improve corrosion resistance?
- No, neither general corrosion nor pitting — the PREN is identical to a 316L. It protects against one specific mechanism, intergranular corrosion after thermal sensitisation. It is a fabrication safeguard, not a media one.
- Why is the carbon higher than in a 316L?
- Because it does not need to be low: titanium captures it as stable titanium carbides instead of letting it form chromium carbides that deplete the grain boundaries. Lowering carbon as well as stabilising would be paying twice for the same protection.