316Ti stainless steel – UNS S31635
Titanium-stabilized Cr-Ni-Mo austenitic stainless steel
Variant of 316 with titanium (≥ 5×(C+N)), which ties up carbon as Ti carbide and prevents sensitization in welding and in service between 425 and 815 °C. Corrosion resistance equivalent to 316; preferred in thick sections and hot service.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | S31635 |
| W.Nr./EN | 1.4571 (X6CrNiMoTi17-12-2) |
| DIN | X6CrNiMoTi17-12-2 |
| JIS | SUS316Ti |
| Trade names | AISI 316Ti |
| Others | V4A (DE) |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM A479 / EN 10088-3 |
| Forging/flange | ASTM A182 F316Ti |
| Plate | ASTM A240 |
| Tube | ASTM A312 TP316Ti |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7222.30.00 | 7222.30 | 7222.30.0024 | 7222 30 51 |
| Hot-rolled bar | 7222.11.00 | 7222.11 | 7222.11.0059 | 7222 11 11 |
| Plate (> 10 mm, width ≥ 600 mm) | 7219.21.00 | 7219.21 | 7219.21.0020 | 7219 21 10 |
| Seamless pipe | 7304.41.90 | 7304.41 | 7304.41.6045 | 7304 41 00 |
| Welded pipe | 7306.40.00 | 7306.40 | 7306.40.5085 | 7306 40 80 |
| Flange and fitting | 7307.21.00 | 7307.21 | 7307.21.5000 | 7307 21 00 |
Tariff class: stainless steel (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM A182 F316Ti / A479
| Element | Range (%) |
|---|---|
| C | ≤ 0.08 |
| Mn | ≤ 2.00 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
| Si | ≤ 1.00 |
| Cr | 16.0 – 18.0 |
| Ni | 10.0 – 14.0 |
| Mo | 2.00 – 3.00 |
| N | ≤ 0.10 |
| Ti | 5×(C+N) – 0.70 |
| Fe | balance |
Mechanical properties
Solution annealed (ASTM A182 F316Ti)
| Property | Value |
|---|---|
| Yield strength (0.2%) | ≥ 205 MPa |
| Tensile strength | ≥ 515 MPa |
| Elongation | ≥ 30% |
| Reduction of area | ≥ 40% |
| Hardness | ≤ 217 HB (typical) |
Typical physical properties
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ |
| Melting range | 1,375 – 1,400 °C |
| Modulus of elasticity | 200 GPa |
| Thermal conductivity (20 °C) | ≈ 15 W/m·K |
| Thermal expansion (20–100 °C) | ≈ 16.5 µm/m·K |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Cryogenic up to ≈ 800 °C (stabilized against sensitization); oxidation ≈ 870 °C. |
| Heat treatment | Solution annealing 1,020 – 1,120 °C with rapid cooling. Optional stabilizing anneal ≈ 870–900 °C. |
| Welding | Good. Ti does not transfer well across the arc: use ER318 (Nb-stabilized 316) or ER316L; E318/E316L for covered electrode. |
| Machining | Machinability lower than carbon steel: it work hardens quickly; use sharp tools, positive rake, constant feed without 'rubbing' and abundant coolant. Ti carbonitrides increase tool wear. |
Filler metal for welding
The wire composition is usually not identical to the material: each page explains why.
Typical applications
- Chemical equipment in thick sections
- Exchangers and vessels operating between 400 and 800 °C
- Exhaust manifolds and expansion joints
- Pulp and paper
- Welded parts that cannot be solution annealed
Alternatives: 316L is enough for service up to ≈ 425 °C (more available); 316H for creep resistance; 317L/904L for more severe corrosion.
316Ti stainless steel: complete guide
What 316Ti stainless steel is
316Ti belongs to the family of austenitic stainless steels. It has the same base as 316L, 16 – 18% chromium, 10 – 14% nickel and 2 – 3% molybdenum, but solves sensitization differently: instead of limiting carbon, it adds titanium in an amount of at least five times the sum of carbon and nitrogen. Titanium forms stable carbides and leaves the chromium free to form the passive film.
Chemical composition and role of the elements
Molybdenum mainly increases resistance to pitting and crevice corrosion in chlorides. Titanium stabilizes the steel against chromium carbide precipitation in long exposures at 450 – 800 °C, a situation in which 316L can also sensitize over time. Nitrogen is limited to 0.10% because it consumes titanium.
Welding and magnetism
Weldable by all processes, without preheating or post-weld heat treatment, with ER318 or ER316L consumables. In the solution-annealed condition it is practically non-magnetic; slight magnetism appears only after cold work, from the formation of strain-induced martensite.
Service temperature and corrosion
Corrosion resistance is that of 316L, with PREN ≈ 23 – 28; in stagnant or heated seawater it suffers pitting and crevice corrosion.
Applications
Heat exchangers, reactors and process piping that operate hot, pulp and paper equipment, exhaust and components exposed to thermal cycling, shafts and machined parts replacing 316L when there is service at temperature.
Supply forms and Dustre services
Round bars and blocks forged in open die, cut to size on a band saw, with rough or finish machining, solution annealing in our own furnaces and hardness, tensile and impact testing. All material is supplied with a 3.1 inspection certificate and heat traceability.
Frequently asked questions
What is the chemical composition of 316Ti stainless steel?
Per ASTM A182 F316Ti / A479: C ≤ 0.08; Mn ≤ 2.00; P ≤ 0.045; S ≤ 0.030; Si ≤ 1.00; Cr 16.0 – 18.0.
Which standards cover 316Ti stainless steel?
Bar: ASTM A479 / EN 10088-3. Forging/flange: ASTM A182 F316Ti. Plate: ASTM A240. Tube: ASTM A312 TP316Ti.
Up to what temperature can 316Ti stainless steel be used?
Cryogenic up to ≈ 800 °C (stabilized against sensitization); oxidation ≈ 870 °C.
Which materials can replace 316Ti stainless steel?
316L is enough for service up to ≈ 425 °C (more available); 316H for creep resistance; 317L/904L for more severe corrosion.
