RFQ Today
Certifications: EN 10204 3.1 / 3.2 material test certificates, PMI verification, and complete export documentation packages.
Titanium
Grade 2
(CP-Ti)
A world-class technical reference for EPC contractors, process and marine engineers, procurement heads, and TPI inspection agencies specifying Titanium Grade 2 commercially pure titanium — covering the CP-Ti grade system, corrosion resistance in chemical process and marine environments, hydrogen embrittlement risk specific to unalloyed titanium, weldability, and the QC and documentation discipline required for critical chemical process, desalination, and marine equipment supply.
the CP Grade System
& Selection Logic
Titanium Grade 2 is a commercially pure (CP, unalloyed) titanium grade — the most widely used of the four standard CP titanium grades, offering an excellent balance of corrosion resistance, weldability, and moderate strength for chemical process, desalination, and marine equipment where the very high strength of alloyed grades such as Ti-6Al-4V (RR Hydraulic’s Titanium Grade 5 reference) is not required.
1.1 — What Titanium Grade 2 (CP-Ti) Means and How It Differs from Grade 5
Titanium Grade 2 (UNS R50400) is unalloyed, commercially pure titanium (CP-Ti) — containing a minimum of 99.2% titanium by weight, with only small, tightly controlled amounts of interstitial elements (oxygen, nitrogen, carbon, hydrogen, iron) present as impurities from the extraction and refining process rather than as deliberate alloying additions. This is a fundamentally different material category from Titanium Grade 5 (Ti-6Al-4V, discussed in RR Hydraulic’s dedicated reference), which is an alpha-beta alloy with substantial deliberate aluminium and vanadium additions specifically engineered for high strength. Grade 2 CP titanium instead relies on controlled oxygen content as the primary mechanism for strength variation across the four standard CP grades (Grades 1 through 4) — Grade 2 sits in the middle of this range, providing a practical, widely available balance of moderate strength, excellent ductility, and the best-established, most extensively documented corrosion performance of any CP titanium grade in industrial chemical process service.
1.2 — The CP Titanium Grade System (Grades 1–4)
| Grade | UNS | Max. Oxygen Content | Min. Yield Strength (MPa) | Typical Use |
|---|---|---|---|---|
| Grade 1 | R50250 | 0.18% | 170 | Maximum ductility/formability — deep drawing, chemical process equipment with complex forming |
| Grade 2 | R50400 | 0.25% | 275 | The most widely used CP grade — general chemical process, desalination, marine, and structural applications |
| Grade 3 | R50550 | 0.35% | 380 | Higher strength than Grade 2 with somewhat reduced ductility — aerospace and higher-load structural applications |
| Grade 4 | R50700 | 0.40% | 480 | Highest-strength CP grade — surgical and precision applications requiring maximum CP strength |
Note the direct relationship: as maximum permitted oxygen (an interstitial strengthening element) increases from Grade 1 to Grade 4, minimum yield strength increases correspondingly — while ductility decreases somewhat. This oxygen-content-driven strength variation, without any deliberate alloying addition, is the defining metallurgical principle of the CP titanium grade system.
1.3 — Key Engineering Properties of Grade 2
Excellent, Well-Documented Corrosion Resistance
Titanium Grade 2’s protective, self-healing titanium oxide (TiO₂) passive film provides outstanding corrosion resistance across an exceptionally broad range of environments — seawater and marine atmospheres, oxidizing acids (nitric acid), chlorine and chlorinated process streams, and most industrial chemical process fluids — with the most extensive published corrosion performance database of any titanium grade, given its decades of established chemical process industry use.
Excellent Weldability
As an unalloyed material without the complex alpha-beta phase transformation behaviour of Ti-6Al-4V, Grade 2 CP titanium is significantly easier to weld reliably — good ductility is retained in the weld and heat-affected zone, and the alloy does not require the same degree of post-weld heat treatment consideration as some alloyed titanium grades, provided standard titanium welding atmosphere control (inert gas shielding to prevent atmospheric contamination) is correctly implemented.
Good Ductility and Formability
Grade 2 offers good cold-forming characteristics for a titanium grade, supporting fabrication of heat exchanger tube, formed vessel components, and other shapes requiring moderate deformation without the springback and forming force challenges of higher-strength alloyed titanium grades.
Moderate Strength at Low Weight
While substantially lower in strength than Ti-6Al-4V, Grade 2’s yield strength (minimum 275 MPa) still exceeds many stainless steel grades in the annealed condition, at titanium’s characteristic low density (4.51 g/cm³ vs. stainless steel’s ~8.0 g/cm³) — providing a meaningful weight advantage for applications where CP titanium’s strength is adequate.
Product Forms
& Mechanical Reference
Titanium Grade 2 is manufactured across tube, pipe, bar, and plate product forms, each governed by a specific ASTM/ASME standard. Full detail on the alloyed Titanium Grade 5 family is available in RR Hydraulic’s dedicated reference.
Submit form, size, and quantity to sales@rrhydraulics.com for a certified offer.
2.1 — Governing Standards
ASTM B265 — Titanium and Titanium Alloy Strip, Sheet, and Plate
Governs flat-rolled titanium product including Grade 2 sheet and plate — used for heat exchanger tube sheets, vessel fabrication plate, and general sheet applications.
ASTM B337 / B338 — Seamless and Welded Pipe
B337 governs seamless titanium pipe; B338 governs welded titanium pipe for condenser and heat exchanger tube specifically — the primary specifications for Grade 2 titanium tube in heat transfer applications, one of the alloy’s most significant use categories.
ASTM B348 — Titanium and Titanium Alloy Bars and Billets
Governs titanium bar and billet stock including Grade 2 — used for machined fasteners, forging billet, and general bar stock applications, shared in general format with the Grade 5 standard discussed in RR Hydraulic’s dedicated reference.
ASTM B861 / B862 — Welded and Seamless Pipe (General)
General titanium and titanium alloy pipe standards covering broader process piping applications beyond the specific condenser/heat exchanger tube scope of B337/B338.
ASME Section II Part B
Publishes design allowable stress values for titanium grades including Grade 2, referenced by ASME Section VIII (pressure vessels) and B31.3 (process piping) for pressure equipment design incorporating titanium components.
2.2 — Composition and Mechanical Properties
| Element / Property | Value / Range |
|---|---|
| Titanium | ≥ 99.2% (balance) |
| Oxygen (max.) | 0.25% |
| Iron (max.) | 0.30% |
| Carbon (max.) | 0.08% |
| Nitrogen (max.) | 0.03% |
| Hydrogen (max.) | 0.015% |
| Tensile Strength | 345–450 MPa (min. 345 MPa per spec) |
| Yield Strength | 275–400 MPa (min. 275 MPa per spec) |
| Elongation | 20–30% |
| Density | 4.51 g/cm³ |
Galvanic Compatibility
& Fabrication Guidance
Commercially pure titanium carries a specific, well-documented hydrogen embrittlement risk mechanism distinct from the general hydrogen embrittlement discussed for coated fasteners elsewhere in RR Hydraulic’s material references — and shares the galvanic and welding considerations relevant across the titanium family.
3.1 — Hydrogen Pickup and Hydride Embrittlement in CP Titanium
3.2 — Galvanic Compatibility
Like Titanium Grade 5 (discussed in detail in RR Hydraulic’s dedicated reference), Titanium Grade 2’s exceptionally stable passive oxide film places it near the noble (cathodic) end of the galvanic series — when CP titanium is placed in electrical contact with a less noble metal (carbon steel, aluminium, or many stainless grades) in a conductive wet or marine environment, the less noble metal corrodes preferentially, potentially accelerating corrosion of the surrounding structural material at the contact interface. This same galvanic design consideration and isolation guidance (non- conductive washers, coatings, or gaskets between titanium and less-noble structural materials) applies to Grade 2 as it does to Grade 5.
3.3 — Welding and Fabrication Guidance
Inert Gas Shielding Requirements
Titanium welding (typically GTAW) requires comprehensive inert gas shielding — not only the torch gas shield but also trailing shields and backing gas purge for the weld root and heat-affected zone — to prevent atmospheric oxygen, nitrogen, and hydrogen contamination of the hot titanium surface, which would otherwise embrittle the weld and adjacent heat-affected zone. Inadequate shielding is a common cause of titanium weld quality problems, particularly for CP Grade 2’s excellent as-supplied ductility being compromised by an improperly shielded weld.
Cleanliness Requirements
Surfaces to be welded must be thoroughly cleaned of oil, grease, and oxide scale, and handled with clean tooling to avoid introducing contamination that could be absorbed into the weld pool at welding temperature — titanium’s high chemical reactivity at elevated temperature makes it considerably more sensitive to surface contamination during welding than most other structural metals.
Machining Characteristics (Compared to Grade 5)
Titanium Grade 2 is generally easier to machine than Ti-6Al-4V (Grade 5) due to its lower strength and simpler single-phase microstructure, though it retains titanium’s characteristic low thermal conductivity (requiring attention to heat management at the cutting edge) and some work-hardening tendency — the fundamental machining principles discussed in RR Hydraulic’s Titanium Grade 5 reference (sharp tooling, controlled cutting parameters, chip/dust fire risk management) apply to Grade 2 as well, though generally with less severe tool wear and cutting force requirements.
Industry Applications
& Documentation
RR Hydraulic maintains full traceability from certified titanium mill heat to finished, tested, and packed Grade 2 component shipment. Chemical composition, mechanical, and NDT verification are standard on all project-grade supply.
4.1 — Inspection & QC Protocol
4.2 — EN 10204 / Documentation Requirements
| Certificate | Content | EPC Requirement | When Mandatory |
|---|---|---|---|
| 2.1 / 2.2 | Declaration / non-specific | Not acceptable for critical process/marine supply | Never for critical chemical process or desalination equipment supply |
| 3.1 (EN 10204) | Heat-traceable chemical + mechanical test report | Mandatory — all EPC supply | All chemical process, desalination, and marine component supply |
| 3.2 (EN 10204) | 3.1 + TPI countersign | Critical / owner-specified critical items | Safety-critical desalination and marine equipment |
4.3 — Applications by Industry
Chemical Process Heat Exchangers
Titanium Grade 2 tube (per ASTM B337/B338) for shell-and-tube heat exchangers and condensers in chemical process, power plant, and desalination applications — the alloy’s outstanding corrosion resistance combined with excellent heat transfer properties and good weldability makes it the standard, most widely specified titanium grade for this critical heat transfer equipment category.
Desalination Plant Equipment
Titanium Grade 2 piping, heat exchanger tube, and vessel components for seawater desalination plants — leveraging the alloy’s exceptional, long-proven seawater and hot brine corrosion resistance across the desalination process’s demanding combination of chloride exposure, temperature, and flow conditions.
Chlor-Alkali and Chemical Process Electrodes
Titanium Grade 2 as the substrate material for coated (typically mixed metal oxide, MMO) anodes in chlor-alkali production and other electrochemical process applications — the titanium substrate’s corrosion resistance and mechanical stability support the electrode’s coating and service life in the aggressive electrochemical process environment.
4.4 — Export Packaging Specification
- Titanium bar, plate, and tube individually protected from surface contamination (particularly iron/steel contact, which can embed and cause localized surface issues) during packing and transit
- Heat/lot number marked or tagged on each item, cross-referenced to the accompanying material test certificate including verified hydrogen content result
- Titanium components segregated from carbon steel and other ferrous materials during packing and storage, consistent with the galvanic and cross-contamination principles discussed in Section 3.2
- Documentation in a waterproof pocket: EN 10204 3.1/3.2 MTC, chemical composition report (including hydrogen content), mechanical properties report, PMI report, NDT reports, and packing list with form/size breakdown per item
- ISPM-15 timber or export cartons for international shipment, with country of origin and HS tariff code documentation matched to the titanium product category
Submit your form, size, and quantity to RR Hydraulic for a complete, certified commercial offer.