Start with the component’s job
The first titanium-selection question is not which Grade number is larger. Bending thin material around a tight radius, carrying load in a connection and exposing process equipment to a fluid create different priorities. Commercially pure Grades 1, 2, 3 and 4 address these needs with different mechanical balances within the unalloyed titanium family. Retaining the same dimensions does not remove the design implications of a grade change. If the drawing has no material designation yet, gather loading, forming and exposure information together. If it already specifies a grade, begin the assessment from that requirement.
Where does the strength increase come from?
The distinction between these four grades does not involve the separate aluminium-and-vanadium alloy system used in Grade 5. Permitted limits for oxygen and other elements change the mechanical behaviour of commercially pure titanium. Grade 1 lies towards the ductility and forming end of the family, while Grade 4 lies towards higher strength; Grades 2 and 3 provide intermediate options. However, a producer’s typical value is not a guaranteed minimum for a different product form. Sheet thickness, bar section and delivery specification identify the condition represented by a mechanical-property entry. Compare products in equivalent conditions first.
Bending depends on more than elongation
Elongation from a tensile test is useful forming information, but it does not alone establish a safe bend radius. Rolling direction, surface marks, edge preparation, thickness and tool geometry also influence the result. A bending approach that works for Grade 1 should not simply be transferred to Grade 4. Series production can be planned around cutting and bending sequence together with sample-part trials. If welding follows, assess the heat input implications and joint shape early. Selection then follows how the finished component will be made rather than focusing solely on the starting sheet. Surface preparation can become particularly important in a tight section.
For example, strips cut from the same sheet can respond differently under the same tooling when bent in different orientations to rolling. Before changing material, check the cutting direction and whether the sample represents actual production conditions. Trial records provide a useful comparison basis for subsequent batches.
Do not confuse annealing with hardening
Annealing and stress relief in commercially pure titanium are used to manage microstructure and stress after forming. Treating them as precipitation-ageing routes to high strength can lead to unsuitable selections. When more mechanical capacity is needed, review grade, section and product specification first. Surface interaction with air also matters during thermal processing; temperature and time should not become a recipe detached from the application procedure. Bar intended for machining additionally requires straightness, surface condition and allowance to be defined. Finished-component tolerance should not be assumed identical to stock tolerance.
Turn the choice into a usable request
Writing grade together with form and delivery condition makes the options genuinely comparable. ASTM B265 addresses flat products, for example, while ASTM B348/B348M covers bars and billets; the same Grade name does not merge these scopes. Include fluid and temperature where corrosion matters. The mechanical progression within the commercially pure family does not establish an identical corrosion outcome in every environment. Identify uncertainties in the initial request instead of filling missing information with assumptions. Product and inspection scope can then be assessed against component requirements. Combining all four grades under one “pure titanium” line loses these distinctions.
- Grade and UNS identity; sheet, plate or bar form.
- Stock dimensions, quantity, bending or machining plan.
- Delivery condition, product standard and inspection documentation.
At a glance
| Grade | Selection emphasis | Manufacturing question |
|---|---|---|
| Grade 1 | High ductility and cold forming | Are both the bending and loading requirements met? |
| Grade 2 | A balanced mechanical option in the CP family | Are form, exposure and delivery condition defined? |
| Grade 3 | A higher strength requirement | Is forming allowance sufficient for the actual geometry? |
| Grade 4 | Higher mechanical capacity within Grades 1–4 | Has reduced ductility been reflected in the production plan? |