How to Choose Between Grade 2 and Grade 4 Titanium?
How to Choose Between Grade 2 and Grade 4 Titanium?
Both Grade 2 and Grade 4 titanium belong to commercially pure titanium.
Grade 2 titanium (Gr2) and Grade 4 titanium (Gr4) both belong to the commercially pure titanium (CP titanium) series. Although both are called pure titanium, the differences in trace element content give them distinct performance characteristics.
Gr2: A commercially pure titanium with balanced performance and good machinability.
Gr4: Higher hardness, strength, and wear resistance. Differences in Chemical Composition and Their Impact on Performance
The main difference between Gr2 and Gr4 lies in their oxygen and iron content. Oxygen plays a strengthening role in titanium; higher oxygen content results in greater strength and hardness, but slightly lower ductility.
|
lement |
Gr2 |
Gr4 |
|
titanium |
balance |
balance |
|
Oxygen (O) |
≤0.25% |
≤0.40% |
|
Iron (Fe) |
≤0.30% |
≤0.50% |
|
Nitrogen (N) |
≤0.03% |
≤0.05% |
|
Hydrogen (H) |
≤ 0.015% |
≤ 0.015% |
Of these chemical components, the oxygen content has the greatest impact on performance. With increasing oxygen content, tensile strength and yield strength increase slightly. This is why GR4 is stronger and harder than GR2, even though both are called commercially pure titanium.
In many aspects, GR4 is actually a reinforced version of pure titanium, rather than a simple alloy.
Mechanical Properties Comparison
|
performance |
Gr2 |
Gr4 |
|
tensile strength |
Approximately 345 MPa |
Approximately 550 MPa |
|
Yield strength |
Approximately 345 MPa |
Approximately 550 MPa |
|
elongation |
Approximately 345 MPa |
Approximately 550 MPa |
|
hardness |
lower |
higher |
|
Cold formability |
excellent |
good |
|
ductility |
better |
lower |
Grade 4 titanium has higher strength and hardness than Grade 2 titanium. However, Grade 2 titanium is easier to process and has better flexibility.
Grade 4 titanium is stronger than Grade 2 titanium because it has a higher content of trace elements such as oxygen. These elements make the internal crystal structure of titanium metal more compact, leaving less room for movement, thus significantly increasing its strength and hardness. However, it is more difficult to process.
Formability and Machining Characteristics
Gr2: Easier to process, good cold forming performance, suitable for processing complex geometries.
Gr4: Higher strength, better wear resistance, but requires higher loads for processing, and has slightly lower ductility.
Corrosion Resistance and Biocompatibility
* Both materials have excellent corrosion resistance, suitable for seawater, chloride, and acidic environments.
* Free of alloying elements such as aluminum and vanadium, therefore has good biocompatibility, suitable for medical and human contact applications.
Gr4: High hardness, good wear resistance, and strong surface durability.
Gr2: Soft texture and excellent ductility.
Selection Recommendation:
Choose the appropriate material based on the specific application environment, site, and background. For high strength and corrosion resistance, choose GR4. For ease of processing, prioritize GR2.
In summary
|
grade |
Core Features |
|
Gr2 |
Optimal operability and balanced performance |
|
Gr4 |
Highest strength and outstanding wear resistance |
bBoth retain the core advantages of commercially pure titanium: low density, strong corrosion resistance, and good biocompatibility. The final choice depends on your application requirements: ease of processing vs. mechanical strength and wear resistance.
For more information on titanium material selection, and to obtain Gr2/Gr4 samples and quotations, please contact us.
