TC2 (Chinese grade) / Ti-6Al-4V (International standard)

（1）Type: α+β Titanium Alloy
（2）Composition:

• Titanium (Ti): Base (approx. 90%)

• Aluminum (Al): 5.5–6.8% (stabilizes the α-phase)

• Vanadium (V): 3.5–4.5% (stabilizes the β-phase)

• Standards: Corresponds to ASTM Grade 5 (USA), BT6 (Russia), and GB/T 3620.1 (China).

OT4 (Russian grade)

（1）Type: Industrial Pure Titanium (α-type titanium alloy)
（2）Composition:

• Titanium (Ti): ≥99% (low impurity content)

• Oxygen (O): ≤0.3% (primarily affects strength)

• Iron (Fe): ≤0.3%

• Standards: ГОСТ 19807-91 (Russia), similar to ASTM Grade 2 (USA) or TA2 (China).

2. Key Performance Comparison

（1）TC2 (Ti-6Al-4V)

• Tensile Strength: 900–1100 MPa

• Yield Strength: 830–950 MPa

• Elongation: 10–15%

• Hardness: 330–360 HV

• Density: 4.43 g/cm³

• Corrosion Resistance: Excellent (especially in seawater corrosion)

• Weldability: Poor (requires inert gas protection)

• Thermal Stability: Stable below 600°C

• Cold Workability: Difficult (requires heat treatment)

（2）OT4 (Industrial Pure Titanium)

• Tensile Strength: 440–620 MPa

• Yield Strength: 350–500 MPa

• Elongation: 20–30%

• Hardness: 150–200 HV

• Density: 4.51 g/cm³

• Corrosion Resistance: Excellent (slightly inferior to alloyed versions)

• Weldability: Excellent (suitable for conventional welding)

• Thermal Stability: Stable below 350°C

• Cold Workability: Good (can be cold-rolled and bent)

3. Application Scenario Differences

（1）TC2 (Ti-6Al-4V)

• Aerospace: Aircraft engine blades, structural components (high strength and lightweight).

• Medical: Artificial joints, bone screws (biocompatibility and high strength).

• Military: Submarine pressure hulls, missile components.

• Drawbacks: High cost ($30–50/kg), difficult to process.

（2）OT4 (Industrial Pure Titanium)

• Chemical Industry: Reaction vessels, pipelines (resistant to acid and alkali corrosion).

• Marine Engineering: Desalination equipment, ship components.

• Consumer: Eyeglass frames, golf clubs (easy to form and aesthetically pleasing).

• Advantages: Low cost ($15–25/kg), easy to process and weld.

4. Core Differences Summary

（1）Strength vs. Ductility:

• TC2 achieves high strength through aluminum and vanadium alloying, but sacrifices ductility.

• OT4, being pure titanium, is softer and more ductile, suitable for cold forming.

（2）Temperature Adaptability:

TC2 maintains performance at high temperatures (up to 600°C), while OT4 is only suitable for medium to low temperatures.

（3）Cost and Processing:
OT4 is cost-effective and suitable for mass production in consumer applications, while TC2 is used in high-value-added fields.

5. Corrosion Resistance and Environmental Adaptability

（1）Corrosion Behavior

• Uniform Corrosion: In a 3.5% NaCl solution, the corrosion rate of TC2 is 0.002mm/a, while OT4's rate is 0.003mm/a. Both are superior to industrial pure titanium.

• Intergranular Corrosion: TC2 welded joints can pass the 61% nitric acid intergranular corrosion test, while OT4 requires an additional 0.1% Pd to suppress sensitization.

（2）Special Environmental Performance

• High-Temperature Oxidation: After 100 hours of oxidation at 500°C in air, TC2's oxidation weight gain is 0.5mg/cm², while OT4's is 0.8mg/cm².

• Stress Corrosion: In a 3.5% NaCl + 3.5% MgCl₂ solution, TC2's stress corrosion threshold (KISCC) is 45MPa·m¹/², while OT4's is 40MPa·m¹/².

6. Conclusion

• Prioritize TC2: In scenarios requiring high weldability and corrosion resistance, such as aerospace structural components and chemical equipment.

• Prioritize OT4: In applications that require short-term use at high temperatures (such as rocket engine components) or in cost-sensitive industries.

7. Contact Us
If you are looking for TC2, OT4, or common metals, we offer various specifications of bars, plates, wires, tubes, and more. We also support tailored processing, heat treatment, and surface treatment services.
Email: sale@bolaibao1.com
Feel free to contact us via phone or email, and we will provide fast, professional, and flexible one-stop services to ensure your projects move forward smoothly and efficiently.