4 CP Titanium Grades Compared
Commercially pure titanium Grades 1, 2, 3 and 4 share the same corrosion-resistant titanium base, but they do not offer the same strength or forming margin. This guide turns the standards data into a clear choice for buyers, designers and fabricators.
.jpg?width=1800)
Choose by the controlling requirement
Do not start with “Which grade is premium?” Start with the part's load, how much it must be formed, the governing product standard and the service environment. The four grades form a strength-versus-ductility ladder.
Complex forming
Best first choice for deep draws, complex sheet shapes and applications where the metal must tolerate the most plastic deformation.
Watch: lowest load capacityBalanced default
The practical starting point for chemical equipment, marine piping and welded fabrications when no single extreme controls the design.
Watch: “default” still needs a standardMore strength
Useful when Grade 2 does not provide enough design strength but the project still needs an unalloyed titanium grade.
Watch: less forming latitudeMaximum CP strength
The strongest of the four CP grades. Common where high strength is valuable and forming is limited or tightly controlled.
Watch: not automatically “best”What does “commercially pure titanium” mean?
The word commercially is important. The metal is supplied to an industrial or medical material specification. It is not described by a single purity percentage and it is not interchangeable simply because two pieces both look silver-gray.
Oxygen and iron are the main variables behind the four-grade ladder. Oxygen sits between atoms in the alpha-titanium crystal structure and makes further deformation more difficult. In plain language, more allowable oxygen generally means more strength—but less stretch before fracture and less room for demanding forming operations.
Iron also contributes to the strength and phase balance. Yet chemistry is only part of the answer. Grain size, cold work, annealing, product form, thickness and test direction can change the measured result. That is why a material certificate must be read together with the purchase standard.
Grade is only one line of the specification
“CP Grade 2 titanium” is not a complete purchase description. A buyer also needs the product form, governing standard, condition, dimensions, surface and testing requirements. ASTM B265 covers annealed strip, sheet and plate. ASTM B348/B348M covers bars and billets. ASTM F67 covers unalloyed titanium mill products used to manufacture surgical implants.
Those standards can use the same Grade 1–4 and UNS names, but that does not make every required property identical. A sheet value should not be copied onto a bar, tube, forging, cold-worked wire or finished implant without checking the applicable document.
CP titanium Grades 1–4: strength and chemistry
The table uses an annealed ASTM/ASME flat-product basis summarized by Nippon Steel. Treat it as a comparison tool, then verify the current governing standard, product thickness and test direction on the order.
| Property | Grade 1 | Grade 2 | Grade 3 | Grade 4 |
|---|---|---|---|---|
| UNS number | R50250 | R50400 | R50550 | R50700 |
| Oxygen, max. | 0.18% | 0.25% | 0.35% | 0.40% |
| Iron, max. | 0.20% | 0.30% | 0.30% | 0.50% |
| Nitrogen, max. | 0.03% | 0.03% | 0.05% | 0.05% |
| Carbon / hydrogen, max. | 0.08% / 0.015% | 0.08% / 0.015% | 0.08% / 0.015% | 0.08% / 0.015% |
| Yield strength, 0.2% offset | 138–310 MPa | 275–450 MPa | 380–550 MPa | 483–655 MPa |
| Ultimate tensile strength | ≥240 MPa | ≥345 MPa | ≥450 MPa | ≥550 MPa |
| Elongation, min. | 24% | 20% | 18% | 15% |
| Simple selection cue | Most formable | Best balance | Higher strength | Highest CP strength |
Source basis: Nippon Steel titanium standards table, summarizing ASTM/ASME flat-product requirements. Chemistry and mechanical acceptance must follow the exact contract standard and revision.
.jpg?width=1300)
What each CP titanium grade does best
Use the profiles below as a screening step. Final selection still depends on the actual load case, geometry, fabrication route, environment and code.
Maximum forming freedom
Grade 1 has the lowest oxygen and iron ceilings of the four. It gives the widest ductility margin and is the clearest starting point for severe sheet forming.
- Best fit: deep-drawn shapes, complex plates, explosive bonding and highly formed heat-exchanger plates.
- Main tradeoff: the lowest strength and load capacity in the group.
- Buyer check: confirm that the lower strength still satisfies the code and design case after forming.
The balanced workhorse
Grade 2 combines useful strength, good ductility, weldability and broad industrial use. It is often the most sensible place to begin—not a grade to select blindly.
- Best fit: chemical equipment, seawater piping, reactor vessels, heat exchangers and welded assemblies.
- Main tradeoff: less forming latitude than Grade 1 and less strength than Grades 3–4.
- Buyer check: do not assume stock condition or actual tensile results from the word “Grade 2.”
A controlled strength step
Grade 3 fills the gap between the general-purpose Grade 2 and the highest-strength Grade 4. It is useful when added strength matters but an unalloyed titanium grade remains desirable.
- Best fit: stronger pressure or fabricated components with moderate forming demands.
- Main tradeoff: a smaller forming window and potentially narrower commercial availability.
- Buyer check: verify the supplier's product form and lead time before locking the design.
The CP strength ceiling
Grade 4 offers the highest minimum strength among the four standard CP grades. It keeps useful ductility, but it is the least forgiving choice for severe forming.
- Best fit: higher-load CP parts, selected medical/dental stock and components where moving to an alloy is not preferred.
- Main tradeoff: the narrowest forming margin in the Grade 1–4 group.
- Buyer check: an implant or aerospace part needs its own material and quality standard; “Grade 4” alone is not approval.
Which grade should you use for your part?
The best grade is the lowest-risk grade that satisfies both manufacturing and service requirements. These routes help narrow the shortlist.
Start with Grade 1
Use when draw depth, complex curvature or forming strain controls the job. Compare with Grade 2 only after the forming trial proves enough margin.
Start with Grade 2
A practical baseline for chemical-processing equipment, marine systems and welded fabrications. Confirm the fluid chemistry and construction code separately.
Compare Grade 3 and Grade 4
Use the real design stress and forming route. Grade 3 preserves more elongation; Grade 4 provides the highest CP strength.
Use the implant standard—not a generic industrial callout
ASTM F67 covers Grades 1–4 for surgical-implant material. Grade 4 is common where higher CP strength helps, but the finished device still needs full validation.
Do not solve corrosion by moving from Grade 2 to Grade 4
Stronger CP titanium may not solve an aggressive acid or crevice problem. Evaluate palladium-, ruthenium- or nickel-containing titanium grades and verify test data.
The oxide film gives titanium broad resistance, but chemistry, temperature, oxygen, flow and crevices decide the boundary.
Do Grades 1–4 have the same corrosion resistance?
They share the same basic corrosion mechanism: a thin, adherent titanium-oxide film forms on the surface and can repair itself when oxygen or water is available. This supports strong performance in many neutral, oxidizing and chloride-containing environments.
That does not make every CP grade safe in every fluid. A higher grade number mainly changes mechanical strength and ductility; it does not create a simple “Grade 4 resists more corrosion than Grade 2” ladder.
Conditions that change the answer
- Strong reducing acids can attack ordinary CP titanium.
- Fluoride-containing media are a major warning condition.
- Anhydrous chlorine is incompatible with titanium.
- High temperature, low oxygen, tight crevices and deposits can weaken passivation.
- Galvanic design, contact surfaces and local boiling conditions can matter more than the CP grade number.
For reducing or severe crevice service, corrosion-resistant titanium grades containing palladium, ruthenium, nickel or molybdenum may be more suitable. The decision needs actual concentration, maximum upset temperature, aeration, flow and geometry—not a general corrosion table copied without test conditions.
Forming, machining and welding CP titanium
The grade changes the forming margin, but process discipline matters across all four grades. Use trials and qualified procedures instead of universal speed, radius or gas-time rules.
Expect springback
Grade 1 offers the widest forming window; Grade 4 the narrowest. Tool radius, rolling direction, thickness, surface condition and temperature all affect the result.
- Do not use one bend-radius number for every thickness.
- Protect the surface from pickup and galling.
- Use a representative forming trial for demanding geometry.
Keep tools engaged
CP titanium conducts heat poorly compared with many shop metals and can gall. Rigid setup, sharp positive tooling and consistent feed help move heat into the chip.
- Use lower speed than a typical steel starting point.
- Avoid rubbing and repeated light passes.
- Use suitable, generous cutting fluid and clean parts before heat or welding.
Shield every hot surface
Grades 1–4 are generally fusion weldable. The critical risk is atmospheric or surface contamination—not an inherent cracking tendency like some high-strength alloys.
- Remove oil, moisture, heavy oxide and iron contamination.
- Shield the pool, trailing hot bead and root with inert gas.
- Qualify filler, heat input and acceptance criteria for the job.
Match the grade to the correct product standard
The same UNS designation can appear in more than one specification. The product form, condition and end use decide which document belongs on the purchase order.
ASTM B265-25
Annealed titanium and titanium-alloy strip, sheet and plate. This is the basis used for the main comparison table.
ASTM B348/B348M-25
Annealed bars and billets. Do not copy sheet requirements onto bar without checking this standard.
ASTM F67-24
Covers chemical, mechanical and metallurgical requirements for Grades 1–4 mill products used to manufacture surgical implants.
ISO 5832-2:2025
Current ISO standard for unalloyed titanium implant material. Its strength-grade system must be checked directly rather than assumed to map one-to-one to ASTM.
Material compliance is not device approval
ASTM F67 covers all four CP grades for surgical-implant material. Grade 4 is frequently selected when higher CP strength is useful, including some dental and orthopedic applications.
However, an ASTM F67 mill certificate does not make a finished implant automatically suitable for a patient or approved by a regulator. The device still needs design validation, manufacturing control, surface and cleaning control, biocompatibility evidence, traceability and the applicable regulatory pathway.
- Specify the medical material standard and revision.
- Maintain heat and lot traceability through machining and surface processing.
- Control cold work, sterilization and finishing because the finished state can differ from the incoming mill product.
- Evaluate the complete device for its intended use.
Grade, product history, surface and full device validation all matter.
CP Grade 4 vs Ti-6Al-4V Grade 5
Move to Grade 5 or another titanium alloy when the design needs strength, fatigue or temperature capability beyond what Grade 4 can provide. Stay with a CP grade when corrosion behavior, weldability, formability or a specific medical or industrial material requirement controls the choice.
Do not compare only one tensile number. A fair selection includes fatigue, fracture behavior, formability, section size, joining, service temperature, corrosion environment, code allowables, supply condition and total manufacturing cost.
Strength is not stiffness
Higher-strength Grade 4 resists permanent deformation better than Grade 1, but the elastic modulus of the CP grades remains broadly similar. Changing from Grade 1 to Grade 4 does not make a thin panel dramatically less flexible under an elastic load. Geometry—especially thickness and section shape—usually has a stronger effect on stiffness.
Can chemistry alone identify the grade?
Not safely in every receiving-inspection situation. Portable XRF can help distinguish titanium from many alloys and can detect heavier alloying elements, but it is weak for light interstitial elements such as oxygen, nitrogen and hydrogen—the same elements that separate CP grades. Use the mill certificate, heat traceability and the specified laboratory methods rather than relying on handheld PMI alone.
CP titanium RFQ checklist
A good purchase specification prevents a correct grade from arriving in the wrong product form, condition, finish or test state.
Grade and UNS
State both, such as Grade 2 / UNS R50400. This prevents confusion with Ti-6Al-4V Grade 5 and with corrosion-modified titanium grades.
Form and standard
Name sheet, plate, strip, bar, billet, tube, forging or wire and the exact governing specification and revision.
Condition and dimensions
State annealed, stress-relieved or cold-worked condition, plus thickness or diameter, tolerance, flatness and test direction.
Finish and cleanliness
Define descaled, pickled, ground, machined or polished condition and any surface-defect or contamination limits.
MTR and traceability
Require heat/lot identity, actual chemistry and mechanical results. “Meets Grade 2” is less useful than the measured values.
Environment and code
State fluid, concentration, maximum normal and upset temperatures, aeration, velocity, deposits, crevices and construction code.
Welding and forming
Identify forming severity, weld procedure, filler, shielding, acceptance and any post-fabrication testing required.
Application requirements
Add NDT, grain-size, medical, pressure-equipment, aerospace or customer-specific requirements only when the design needs them.
Send the grade, thickness, joint and target result.
Oceanplayer can help you frame a sample test for laser welding, cleaning or marking. Include the actual grade and certificate data so the test reflects the production material—not a generic piece of titanium.
Related engineering guides
These Oceanplayer pages add context on titanium, material cost, bend design and laser welding. Each link is taken from the current published-page registry.
CP titanium grade FAQ
Short answers to the questions buyers and engineers most often ask before choosing a grade.
What are the four CP titanium grades?
ASTM Grades 1, 2, 3 and 4 are unalloyed titanium grades identified by UNS R50250, R50400, R50550 and R50700. From Grade 1 to Grade 4, minimum strength rises while guaranteed elongation generally falls.
Which CP titanium grade is strongest?
Grade 4 is the strongest of the standard Grade 1–4 CP family. On the annealed flat-product basis used in this guide, it has a minimum UTS of 550 MPa and a specified yield-strength interval of 483–655 MPa.
Which CP titanium grade is easiest to form?
Grade 1 is the normal starting point for the most demanding forming because it has the lowest strength and highest minimum elongation of the four. Actual success still depends on thickness, rolling direction, tooling, finish and forming temperature.
Why is Grade 2 called the workhorse?
Grade 2 offers a useful balance of strength, ductility, corrosion resistance and weldability. It appears widely in chemical, marine and heat-transfer equipment. “Workhorse” describes its broad usefulness; it is not a substitute for checking the design.
Does a higher CP grade resist corrosion better?
No simple ranking applies. Grades 1–4 share titanium's passive oxide-film behavior. The fluid chemistry, temperature, oxygen level, flow, deposits and crevice geometry usually control whether ordinary CP titanium is suitable.
Is Grade 4 titanium the same as Grade 5?
No. Grade 4 is commercially pure, unalloyed titanium. Grade 5 is Ti-6Al-4V, an alloy containing aluminum and vanadium with a different strength and processing profile.
Can CP titanium be welded?
Yes. Grades 1–4 are generally fusion weldable when the joint is clean and the weld pool, hot bead, heat-affected zone and root are protected by inert gas. A qualified procedure must define shielding, filler and acceptance.
Can XRF tell Grade 1 from Grade 4?
Handheld XRF is not a reliable stand-alone method for separating CP grades because their key differences include light elements such as oxygen and nitrogen. Use traceability, the mill certificate and suitable laboratory testing.
Is ASTM F67 Grade 4 automatically approved for an implant?
No. ASTM F67 defines requirements for unalloyed titanium implant material. A finished device still needs design, processing, surface, biocompatibility, traceability and regulatory controls for its intended use.
What should be written on a CP titanium purchase order?
State the grade and UNS number, product form, standard and revision, condition, dimensions and tolerances, surface, test direction, MTR and heat traceability, plus any code, NDT, medical or customer-specific requirements.
Sources used for this guide
Property values and boundaries were rebuilt from standards pages and producer or welding-authority technical references rather than copied from the unsupported pricing and anecdotal claims in the source draft.
- ASTM B265-25 — annealed titanium and titanium-alloy strip, sheet and plate.
- ASTM B348/B348M-25 — annealed titanium and titanium-alloy bars and billets.
- ASTM F67-24 — unalloyed titanium for surgical-implant applications.
- ISO 5832-2:2025 — unalloyed titanium implant material.
- Nippon Steel titanium standards and properties guide — comparison values and product-standard context.
- ATI CP Grades 1–4 technical data sheet — grade chemistry, fabrication and property context.
- TIMET titanium-alloy overview — oxygen/iron control and CP-grade strength progression.
- TIMET corrosion-resistance handbook — titanium environment limits and corrosion selection.
- TWI: Weldability of titanium and titanium alloys — cleanliness, gas shielding and contamination risks.
- FDA recognition entry for ASTM F67-24 — current U.S. consensus-standard recognition context.