CP Titanium Grades 1–4 Compared: Which Should You Choose?
CP titanium Grades 1–4 mainly trade formability for strength. Grade 1 is the easiest to form; Grade 2 balances strength and fabrication; Grades 3 and 4 provide more strength with less ductility. The best choice is the grade that meets the part’s load, forming and service requirements—not simply the highest number. Always check the product standard and supplied condition.
Titanium sheet produced from powder at Oak Ridge National Laboratory.
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What are the main differences between titanium Grades 1, 2, 3 and 4?
Compare strength and ductility on the same basis. These are reference limits from Nippon Steel’s ASTM/ASME comparison—not measured results for every piece of titanium.
Strength is in MPa; chemistry limits are mass %. The applicable product specification, edition and test conditions govern an order. Swipe the table horizontally on smaller screens.
| Property | Grade 1 | Grade 2 | Grade 3 | Grade 4 |
|---|---|---|---|---|
| UNS identifier | R50250 | R50400 | R50550 | R50700 |
| Tensile strength, minimum | 240 MPa | 345 MPa | 450 MPa | 550 MPa |
| 0.2% proof stress, specified interval | 138–310 MPa | 275–450 MPa | 380–550 MPa | 483–655 MPa |
| Elongation, minimum | 24% | 20% | 18% | 15% |
| Oxygen, maximum | 0.18% | 0.25% | 0.35% | 0.40% |
| Iron, maximum | 0.20% | 0.30% | 0.30% | 0.50% |
| Nitrogen, maximum | 0.03% | 0.03% | 0.05% | 0.05% |
| Carbon / hydrogen, maximum | 0.08% / 0.015% | 0.08% / 0.015% | 0.08% / 0.015% | 0.08% / 0.015% |
Data: Nippon Steel, Standards of Titanium Products, pp. 16–17. This producer summary is a screening reference, not a substitute for the specified standard or the material test report.
How should you read the strength and elongation values?
Tensile strength is the highest engineering stress reached during the tensile test. 0.2% proof stress is a defined measure of resistance to permanent deformation, often called yield strength in selection guides. Neither number is a finished part’s safe working stress.
Elongation measures how much a test specimen lengthens before fracture. It helps compare ductility, but 24% elongation does not mean a sheet can safely take 24% strain in any bend. Specimen geometry, gauge length and direction matter.
Check whether a supplier’s number is a minimum requirement, typical value or actual test result. Also match thickness, condition and test direction. A cold-worked bar should not be compared directly with an annealed sheet using one headline value.
Universal testing machine at the Oregon Department of Transportation materials laboratory.
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What does commercially pure titanium mean?
Commercially pure (CP) titanium is unalloyed titanium with controlled limits for other elements. It is not chemically perfect, 100% titanium. Small amounts of oxygen, iron, nitrogen, carbon and hydrogen can remain within the grade’s requirements.
Oxygen is especially important: it can strengthen titanium while reducing its ability to stretch and form. Controlled chemistry gives Grades 1–4 their different property levels. “Higher grade” therefore does not mean “purer,” “better made” or “best for every part.”
The grade is only part of the description. Rolling, cold work and heat treatment also affect the delivered material. Ask for the grade and product form, specification and condition. TIMET’s alloy overview explains the role of oxygen and iron in CP titanium.
Do not identify titanium by appearance. Two pieces can look the same and have different grades, strength or processing histories. The certificate and heat/lot traceability must match the material you actually receive.
Titanium crystals showing the appearance of the metal.
Which CP titanium grade fits your application?
Start with the requirement that is hardest to meet. Then check whether the candidate also meets the remaining design and manufacturing needs.
Grade 1: for demanding forming
Consider Grade 1 when a part needs substantial drawing, shaping or bending and the design can accept its lower strength. It gives the largest ductility margin within the four-grade comparison.
Where it helps: formed covers, liners and other thin components where making the shape is more difficult than carrying the load.
Check before choosing: dent resistance, permanent deformation, minimum wall after forming and whether the finished shape meets the drawing. Easier forming does not remove the need for a trial.
Grade 2: a general-purpose starting point
Consider Grade 2 for many welded or moderately formed components. It offers a useful balance when Grade 1 is too soft but the design does not need the strength of Grades 3 or 4.
Where it helps: evaluating process equipment, heat-transfer components and corrosion-resistant fabrications—after checking the actual environment.
Check before choosing: available product form, design stress, forming route and joining requirements. Broad use is not evidence that Grade 2 suits an untested chemical duty.
Grade 3: more strength with a forming trade-off
Consider Grade 3 when Grade 2 does not provide enough strength and the component does not require the most severe forming. It provides an intermediate option before moving to Grade 4.
Where it helps: a part whose load requirement justifies the strength increase while its geometry remains practical to manufacture.
Check before choosing: stock availability, springback, tooling loads and the need for extra forming stages. A modest material gain may not justify a difficult production route.
Grade 4: the highest strength of Grades 1–4
Consider Grade 4 when higher CP strength is necessary and the process can accept lower ductility. It remains unalloyed titanium; it is not the same material as Grade 5.
Where it helps: strength-controlled parts that specifically require CP titanium and can be machined or formed by a suitable route.
Check before choosing: forming difficulty, surface condition, joining and the specified product standard. Do not treat Grade 4 as an automatic upgrade for corrosion resistance or elastic stiffness.
How do you choose a grade for a formed component?
Use the real shape, not just the alloy name. A deeply formed plate and a flat bracket may need different grades even when they will see the same fluid.
For a formed heat-exchanger plate, for example, screen the fluid compatibility first. Then compare the candidate grades against the plate pattern, local thinning, forming direction and pressure design. Grade 1 may help a difficult forming operation; Grade 2 may be appropriate if the required shape and strength can both be achieved.
- Define the limits: thickness after forming, allowable distortion, crack acceptance and required service performance.
- Trial the production material: use the actual thickness, condition, rolling direction and tooling.
- Inspect the result: check cracks, thinning, geometry and any required pressure or leak evidence.
- Stop if either side fails: a crack-free part with insufficient strength is not acceptable; a strong material that cannot form reliably is not a solution.
Illustrative selection example, not a reported Oceanplayer Laser trial or a pressure-equipment design approval.
Plate heat exchanger illustrating a formed-plate equipment design.
Titanium plates with colored anodized surface patterns.
Does a higher CP titanium grade resist corrosion better?
No simple Grade 1-to-4 corrosion ranking applies. All four rely on titanium’s protective oxide film. The actual liquid or gas, temperature and surface conditions can matter more than the grade number.
Check normal operation and upset conditions. Reducing acids, fluoride-containing solutions and hot crevices can require a different material choice. Titanium can react dangerously with dry chlorine; suitability in wet service must not be carried over to dry gas service.
Provide the corrosion specialist with concentration, maximum temperature, aeration, deposits, flow and crevice details. Corrosion-modified titanium grades may be worth considering, but “use Grade 4” is not a substitute for this review.
TIMET’s corrosion handbook gives environment-specific laboratory data and recommends testing under the anticipated operating conditions.
How do the grades affect forming, machining and welding?
Choose the manufacturing route along with the material. A stronger grade can change forming loads and tool demands without making the finished component more useful.
Forming: validate radius and springback
Grade 1 generally gives more room for difficult shapes. Higher strength can increase forming force and springback—the amount a part opens after the load is removed.
Do not assign a universal minimum bend radius from the grade alone. Include thickness, grain direction, edge quality, tooling and temperature. A trial bend in the real material is more useful than a generic radius chart.
Machining: use titanium-specific cutting data
Avoid treating CP titanium like ordinary mild steel. A rigid setup, sharp tools and a suitable cooling strategy help control heat, rubbing and surface damage.
Use the cutting-tool supplier’s starting data for the grade and operation, then confirm tool life and part quality. The lowest raw-material strength does not automatically produce the lowest machining cost.
Welding: protect the hot titanium
CP titanium can be fusion welded, but contamination can make the joint brittle. Cleaning and inert shielding must cover the weld pool, hot bead and affected surfaces, including the root where exposed.
For TIG or laser welding, define joint preparation, shielding, any filler and acceptance in a qualified procedure. A clean-looking bead alone does not prove the joint’s ductility or internal quality.
Fabrication references: ATI CP Grades 1–4 data sheet and TWI’s titanium weldability guide. Neither is a machine-specific parameter sheet.
Gas tungsten arc welding with a torch and filler rod.
Which material standard should you specify?
“Grade 2 titanium” is incomplete. Select the specification for the product you are buying and state its required edition on the order.
ASTM B265 covers annealed titanium and titanium-alloy flat products. Dimensions, condition and test requirements still belong in the order.
ASTM B348/B348M is the relevant specification family for titanium bars and billets. Do not automatically apply a flat-product property table to the supplied bar condition.
ASTM F67 covers four unalloyed titanium grades for surgical-implant material. Compliance of the raw material is not approval of a finished medical device.
ISO 5832-2:2025 covers unalloyed titanium and lists six strength-based grades. Check the actual requirements; matching a grade number is not enough.
How can you verify the grade when material arrives?
Match the heat or lot marking to the material test report (MTR). Check the standard, grade, dimensions, condition, chemical results and mechanical results. Resolve missing or inconsistent identity before cutting up the stock and losing its markings.
Handheld X-ray fluorescence (XRF) can help identify many alloying elements, but a displayed alloy name does not prove compliance with a CP grade. Its measurement capability must include the elements that distinguish the material. Common handheld alloy analyzers do not measure oxygen, nitrogen and hydrogen; suitable laboratory methods may be needed.
Oxygen limits can overlap between grades, so one chemistry result is not a complete grade certificate either. The material must satisfy the full specification, including the required mechanical properties and traceability.
For instrument scope, see Evident’s listed handheld XRF element capabilities. The G6 LEONARDO analyzer illustrates the separate inert-gas-fusion approach for oxygen, nitrogen and hydrogen.
Is Grade 4 titanium the same as Grade 5?
No. Grade 4 is CP titanium; Grade 5 is Ti-6Al-4V. Grade 5 intentionally contains roughly 6% aluminum and 4% vanadium. It has a different property and processing profile, rather than being one more step in the same CP series.
If Grade 4 cannot meet a design’s strength requirement, a titanium alloy may be worth evaluating. But compare its forming, fatigue, joining, service environment and supplied condition—not only tensile strength. Changing to Grade 5 is a material change that needs approval, not an informal substitution.
Will Grade 4 make a flexible Grade 1 part much stiffer?
Not simply because it is stronger. Strength controls resistance to permanent deformation; stiffness controls elastic deflection. The CP grades have broadly similar elastic modulus, so a thin panel can remain flexible after moving to a stronger grade.
When excessive flex is the problem, review thickness, shape and support spacing as well as the alloy. When permanent bending is the problem, the higher proof stress may be useful. These are different design checks.
Reference: TIMET’s typical-property comparison lists similar modulus ranges for the CP grades. Typical producer data are not design allowables.
What should a CP titanium purchase order include?
Make the material identity, delivered state and acceptance evidence clear enough that both parties are pricing and inspecting the same product.
State grade and UNS number, sheet/plate/bar or other form, required specification and edition. Do not allow a different grade or standard to be substituted without approval.
State the supplied condition, thickness or diameter, tolerances, flatness/straightness and finish. Add surface-defect and cleanliness requirements relevant to forming or welding.
Require actual chemistry and mechanical results with heat/lot identity. Clarify the test direction, specimen basis and any additional inspection required by the product specification.
Identify the service environment and applicable design code. Include critical forming or joining requirements, and define who resolves nonconforming results before the stock is used.
Compare complete cost, not just price per kilogram. Ask for the same grade, form, condition, quantity, certification and delivery basis. Include forming yield, machining time, scrap and any extra testing. Grade numbers do not create a universal price ladder.
CP titanium grade names and equivalents
Is ASTM Grade 2 the same as JIS Class 2?
Do not assume so. Nippon Steel lists different chemistry and tensile-property requirements for these two designations. A supplier cross-reference can help you find a candidate, but equivalence must be checked against the specified product standards and the actual certificate. An identical number is not proof of interchangeable material.
What is the difference between Grade 2 and Grade 2H?
In ASTM B265, Grade 2H has the same corresponding chemistry as Grade 2 but a higher guaranteed minimum tensile strength of 400 MPa (58 ksi). It is not a new alloy composition. The standard permits 2H material to be certified to the corresponding numeric grade; ordinary Grade 2 material is not automatically certified as 2H. Use the exact designation required by the design and purchase specification.
Designation references: Nippon Steel’s ASTM/JIS comparison and ASTM B265 scope and H-grade note.
Planning a laser process on titanium?
Share the certified grade, product form, thickness, joint or surface condition, and required result with Oceanplayer Laser. Include drawings or photos so the application discussion starts with the real part.
Technical sources
The comparison uses public producer data and standards scopes. For acceptance or design, use the specified standard, current project requirements and traceable material results.
- Nippon Steel: Standards of Titanium Products — CP chemistry, tensile-property limits and ASTM/JIS differences.
- TIMET: Titanium Alloys — CP strengthening, typical property comparisons and Ti-6Al-4V context.
- ATI: CP Grades 1–4 Technical Data Sheet — fabrication and specification context.
- TIMET: Corrosion Resistance of Titanium — conditions that affect material compatibility.
- TWI: Weldability of Titanium and Titanium Alloys — contamination, shielding and embrittlement.
- ASTM B265-25 and ASTM F67-24 — flat-product and implant-material specification scopes.
- ISO 5832-2:2025 — unalloyed titanium for implant manufacture and its strength-based grade system.