Titanium Grade 2 – UNS R50400
Commercially pure (CP) titanium, general-purpose grade
Commercially pure alpha-structure titanium, with strength controlled by the oxygen and iron contents. It is the most used grade in the chemical industry for its combination of corrosion resistance in oxidizing and chlorinated media, good ductility and weldability. Not hardenable by heat treatment.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | R50400 |
| W.Nr./EN | 3.7035 (Ti 2) |
| DIN | DIN 17850 Ti 2 |
| JIS | JIS H 4600 Class 2 (TP340) |
| Trade names | CP Ti Gr 2, Ti40 |
| Others | GB TA2; ASME SB-348/SB-265/SB-338 Gr 2 |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM B348 Gr 2 |
| Plate | ASTM B265 Gr 2 |
| Forging/flange | ASTM B381 F-2 |
| Tube | ASTM B338 Gr 2 (exchanger) / B861 (seamless) / B862 (welded) |
| Fittings | ASTM B363 WPT2 |
| Implant | ASTM F67 Gr 2 |
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 | 8108.90.00 | 8108.90 | 8108.90.6031 | 8108 90 30 |
| Hot-rolled bar | 8108.90.00 | 8108.90 | 8108.90.6031 | 8108 90 30 |
| Plate (> 10 mm, width ≥ 600 mm) | 8108.90.00 | 8108.90 | 8108.90.6045 | 8108 90 50 |
| Seamless pipe | 8108.90.00 | 8108.90 | 8108.90.6060 | 8108 90 60 |
| Welded pipe | 8108.90.00 | 8108.90 | 8108.90.6060 | 8108 90 60 |
| Flange and fitting | 8108.90.00 | 8108.90 | 8108.90.3060 | 8108 90 90 |
Tariff class: titanium (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 B348 Gr 2 (% by mass)
| Element | Range (%) |
|---|---|
| N | ≤ 0.03 |
| C | ≤ 0.08 |
| H | ≤ 0.015 |
| Fe | ≤ 0.30 |
| O | ≤ 0.25 |
| Residuals (each) | ≤ 0.10 |
| Residuals (total) | ≤ 0.40 |
| Ti | balance |
Mechanical properties
annealed (ASTM B348, room temperature)
| Property | Value |
|---|---|
| Yield strength (0.2%) | ≥ 275 MPa |
| Tensile strength | ≥ 345 MPa |
| Elongation (4D) | ≥ 20% |
| Reduction of area | ≥ 30% |
| Hardness | ≈ 160 – 200 HV (typical) |
Typical physical properties
| Property | Value |
|---|---|
| Density | 4.51 g/cm³ |
| Melting range | ≈ 1,660 – 1,670 °C |
| Modulus of elasticity | ≈ 103 – 105 GPa |
| Thermal conductivity (20 °C) | ≈ 16 – 22 W/m·K (typical) |
| Thermal expansion (20–100 °C) | ≈ 8.6 µm/m·K |
| Beta transus | ≈ 900 – 925 °C |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | ASME Section VIII allows use up to 316 °C; oxidation and O/N pickup become relevant above ~425 °C. Keeps toughness at cryogenic temperatures. |
| Heat treatment | Supplied annealed. Annealing 650 – 760 °C, 0.5 – 2 h, air cooling. Stress relief 480 – 595 °C, 0.25 – 4 h. Does not harden by heat treatment. |
| Welding | Good weldability by TIG (GTAW), plasma, laser and electron beam, with AWS A5.16 ERTi-2 (or ERTi-1) filler. Requires argon shielding of the pool, the bead (trailing shield) and the root until below ~430 °C. Do not fusion weld to steel or stainless (forms brittle intermetallics). |
| Machining | Machinable with sharp carbide tools, low speed, constant feed and abundant coolant; tends to gall and fine chips are flammable. |
Typical applications
- Seawater heat exchangers and condensers
- Chlor-alkali and pulp bleaching (ClO2) equipment
- Chemical process vessels, tanks and piping
- Desalination
- Electroplating (anode baskets, racks)
- Non-structural aircraft ducts and components
- Implants and instruments (ASTM F67)
Alternatives: Gr 1 for maximum formability; Gr 3/Gr 4 for more strength; Gr 7, Gr 16 or Gr 12 in reducing acids or where crevice corrosion is a risk above ~70 °C; Gr 5 when mechanical strength is the main requirement.
Titanium Grade 2: complete guide
What titanium Grade 2 is
Grade 2 belongs to the family of titanium and its alloys, in the group of commercially pure (CP) grades, numbered 1 to 4 according to the oxygen and iron content: the more interstitials, the higher the strength and the lower the ductility. Grade 2 is the most used balance between strength, formability and weldability. The structure is hexagonal close-packed (alpha phase) up to the beta transformation, around 900–925 °C in Grade 2, non-magnetic, and the material does not harden by heat treatment.
Chemical composition
ASTM B348 limits nitrogen to 0.03%, carbon to 0.08%, hydrogen to 0.015%, iron to 0.30% and oxygen to 0.25%, with residuals of up to 0.10% each and 0.40% in total; titanium is the balance.
Welding
Titanium welds well by TIG and MIG with ERTi-2 consumable, but is very reactive above about 430 °C: the pool, the root and the cooling bead need high-purity argon shielding, purging and a trailing shield. Bead color is the acceptance criterion: silver and straw pass, blue requires evaluation and purple, gray or white fail. Tools, brushes and grinding wheels must be dedicated to titanium.
Corrosion and limits of use
The passive TiO2 film, which regenerates in the presence of oxygen or water, makes Grade 2 practically immune to seawater and brines up to about 70–80 °C (above that it may suffer crevice corrosion, and Grade 7 is the choice), wet chlorine, hypochlorites, hot chlorides, nitric acid and organic acids, without pitting or stress corrosion cracking. Titanium does not resist hydrofluoric acid and fluorides, hot concentrated hydrochloric and sulfuric acids, dry chlorine or anhydrous methanol; for crevices in hot chlorides Grade 7, with palladium, is used. Use under the ASME code goes up to about 315 °C. Thermal conductivity is low, about one third that of carbon steel; the excellent performance in exchangers comes from the thin wall made possible and the absence of fouling and corrosion.
Applications
Seawater heat exchangers and condensers, desalination plants, chlor-alkali cells and equipment, electroplating baskets and hooks, tanks and piping for oxidizing chemical processes, pulp bleaching equipment, offshore oil and gas components, medical equipment and architectural parts. For high mechanical strength, the Grade 5 alloy.
Supply forms and Dustre services
Round bars cut to size on a band saw, with rough or finish machining and hardness and tensile testing. All material is supplied with a 3.1 inspection certificate and heat traceability.
Frequently asked questions
What is the chemical composition of Titanium Grade 2?
Per ASTM B348 Gr 2 (% by mass): N ≤ 0.03; C ≤ 0.08; H ≤ 0.015; Fe ≤ 0.30; O ≤ 0.25; Residuals (each) ≤ 0.10.
Which standards cover Titanium Grade 2?
Bar: ASTM B348 Gr 2. Plate: ASTM B265 Gr 2. Forging/flange: ASTM B381 F-2. Tube: ASTM B338 Gr 2 (exchanger) / B861 (seamless) / B862 (welded). Fittings: ASTM B363 WPT2. Implant: ASTM F67 Gr 2.
Up to what temperature can Titanium Grade 2 be used?
ASME Section VIII allows use up to 316 °C; oxidation and O/N pickup become relevant above ~425 °C. Keeps toughness at cryogenic temperatures.
Which materials can replace Titanium Grade 2?
Gr 1 for maximum formability; Gr 3/Gr 4 for more strength; Gr 7, Gr 16 or Gr 12 in reducing acids or where crevice corrosion is a risk above ~70 °C; Gr 5 when mechanical strength is the main requirement.
