Titanium Grades and Alloys: A Guide to Picking the Perfect One for Your CNC Project

In our previous article, we explored how titanium alloys strike an excellent balance between weight, strength, corrosion resistance, and environmental stability, making them an indispensable high-end material in precision CNC machining.

But titanium alloys are not a single material—their properties vary significantly depending on grade and composition.

In this blog, we systematically review the most common industrial titanium grades, comparing their composition, key properties, advantages, and typical applications, providing clear guidance for material selection and design decisions in titanium CNC machining projects.

Key Takeaways:

• Titanium is not one material—grade selection matters.Titanium alloys vary significantly by microstructure (α, α+β, β).

• Ti-6Al-4V (Grade 5 / TC4) is the safest and most versatile choice for CNC machining.

• Always confirm the grade standard (ASTM vs. GB), material condition (annealed vs. heat-treated), and performance priorities. Early coordination with an experienced titanium CNC machining partner prevents cost overruns and manufacturing risks.

1. Classification by Microstructure

Titanium alloys are categorized by their dominant microstructure at room temperature. This structure directly dictates how the metal behaves during cnc titanium machining.

1.1 Commercially Pure Titanium (Unalloyed，α alloys)

Grade 1 Titanium

• Type: Unalloyed, α Phase.

• The softest and most ductile grade. Offers maximum formability and excellent corrosion resistance, but the lowest strength.

• Common CNC Applications: Chemical processing linings, heat exchanger plates, and architectural components.

Grade 2 Titanium

• Type: Unalloyed, α Phase.

• The most widely used pure titanium. Provides the best balance of strength, ductility, weldability, and corrosion resistance. It is the standard “workhorse” grade.

• Common CNC Applications: Marine components, chemical piping, medical device housings, automotive exhaust systems, and fluid handling systems.

Grade 3 Titanium

• Type: Unalloyed, α Phase.

• A medium-strength pure titanium. Offers higher strength than Grade 2 while maintaining good formability.

• Common CNC Applications: Aerospace hydraulic tubing, chemical processing equipment, and pressure vessels.

Grade 4 Titanium

• Type: Unalloyed, α Phase.

• The strongest of the pure titanium grades. Used when higher strength is required alongside excellent corrosion resistance, though formability is reduced.

• Common CNC Applications: Aerospace fasteners, surgical bone screws, orthopedic cables, and high-strength corrosion-resistant structures.

1.2 α and near-α alloys

Titanium α and near-α alloys is excellent for high-temperature stability and weldability.

Grade 6 Titanium (Ti-5Al-2.5Sn)

• Type: α Alloy.

• A classic alloy known for good weldability, stability at elevated temperatures (up to ~900°F / 480°C), and excellent corrosion resistance. It cannot be heat-treated for increased strength.

• Common CNC Applications: Aircraft engine casings, airframe components, and cryogenic vessels.

1.3 α+β alloys

The most common category for high-strength structural applications. Can be heat-treated.

Grade 5 Titanium (Ti-6Al-4V)

• Type: α-β Alloy.

• The “workhorse” of titanium alloys, accounting for over 50% of all titanium usage. Renowned for its outstanding strength-to-weight ratio, good fatigue resistance, and excellent corrosion resistance. It can be solution treated and aged to increase strength.

• Common CNC Applications: Aerospace structural components, jet engine parts, high-performance automotive and racing parts, medical implants (non-ELI), and marine fittings.

Grade 23 Titanium (Ti-6Al-4V ELI)

• Type: α-β Alloy (ELI: Extra Low Interstitial).

• A purer, medical-grade version of Grade 5. Lower oxygen and iron content provides enhanced fracture toughness, better fatigue crack resistance, and superior biocompatibility.

• Common CNC Applications: The premium choice for critical medical implants like orthopedic joint replacements, spinal fusion cages, and dental implants.

1.4 β and near-β alloys

Offer the highest strength, excellent hardenability, and good cold formability.

Beta C Titanium (Ti-3Al-8V-6Cr-4Mo-4Zr)

• Type: β Alloy.

• Known for exceptional resistance to stress corrosion and superb corrosion resistance in saline environments. Can achieve very high strength after aging.

• Common CNC Applications: Marine components, chemical processing equipment, high-performance springs, and fasteners.

Ti-10V-2Fe-3Al

• Type: Near-β Alloy.

• Known for deep hardenability, allowing large cross-sections to be heat-treated to very high strength with good toughness.

• Common CNC Applications: Aircraft landing gear components, critical airframe forgings, and other high-strength structural aerospace parts.

Ti-15V-3Cr-3Sn-3Al

• Type: β Alloy.

• Offers exceptional cold roll formability in the solution-treated condition, similar to stainless steel. Can be aged to high strength levels.

• Common CNC Applications: Aerospace sheet metal components, honeycomb panels, springs, and brackets.

Ti-13Nb-13Zr

• Type: Near-β Alloy.

• A biomedical-specific alloy. Its low elastic modulus is closest to human bone, minimizing stress shielding. It offers excellent biocompatibility and corrosion fatigue strength.

• Common CNC Applications: Advanced orthopedic and dental implants.

2. Performance Comparison of Common Industrial Titanium Alloys

Tip for CNC machining: Gr5 (Ti-6Al-4V) is the most mature titanium CNC machining material. β alloys, while stronger, have lower thermal conductivity and are stickier, demanding more from tooling and cooling.

3. Common Titanium Grades in China

In China, titanium grades typically follow GB/T (China), HB (aerospace), and ASTM (US) standards. Names may vary, but the material is essentially the same.

3.1 Naming Rules

TA: α-type titanium alloys (including industrial pure titanium)

TB: β-type titanium alloys

TC: α+β-type titanium alloys (most widely used in CNC titanium parts)

3.2 TA Series: Industrial Pure Titanium

TA2 is the most popular for custom CNC titanium parts due to stable supply, reasonable cost, and superior machinability.

3.3 TC Series: α+β Alloys (Core CNC Materials)

TC4: Corresponds to ASTM Gr5 (Ti-6Al-4V), high strength, excellent fatigue resistance, widely used in robotics, UAVs, aerospace, and precision CNC titanium machining.

TC4 ELI: Extra Low Interstitials, ASTM Gr23, higher toughness, medical-grade. Used for implants and high-reliability components.

TC11: High-temperature α+β alloy, used for aerospace engine hot-section components.

3.4 TB Series: β Alloys

Mainly used in aerospace, military, or research. Rarely used in commercial CNC machining due to high cost, complex heat treatment, and unstable supply.

3.5 Common China & USA Titanium Grades Table

Common Titanium Grades & Applications (China & USA)

4. How to Choose the Right Titanium Alloy for Your CNC Project?

Selecting the optimal titanium grade is a crucial first step that balances performance, manufacturability, and budget.

Here’s a simple decision guide to point you in the right direction:

For Maximum Corrosion Resistance & Formability

Choose: Commercially Pure Titanium (Grades 1 & 2 / TA1 & TA2)

Best For: Electrochemical components, marine hardware, non-load-bearing medical devices, and enclosures requiring complex cold forming.

• For the Best All-Around Performance & Value

Choose: Ti-6Al-4V (Grade 5 / TC4)

Best For: The vast majority of structural components, load-bearing frames, landing gear parts, and standard medical implants. This is the universal first choice when you’re unsure. Most precision CNC machined titanium parts and custom CNC titanium parts successfully use this versatile alloy.

• For High-Temperature Applications (>300°C / 570°F)

Choose: High-Temperature Alpha-Beta Alloys (e.g., TC11)

Pro-Tip from Our Shop: Our extensive CNC machining titanium experience with TC11 shows it has a stronger tendency to work-harden than TC4. We recommend more conservative cutting parameters to ensure quality.

Best For: Jet engine components (non-blades), high-speed airframe skins, and high-temperature hydraulic tubing.

• For Ultra-High Strength & Maximum Weight Savings

Choose: Beta Alloys (e.g., Beta-C, Ti-10V-2Fe-3Al)

Best For: Weight-critical, high-stress components like aerospace fasteners and racing suspension links, as well as parts requiring complex cold heading.

• For Superior Biocompatibility & Fatigue Performance

Choose: Medical-Grade Ti-6Al-4V ELI (Grade 23)

Best For: Long-term implants like hip joints, knee replacements, and bone plates/screws. Its extra-low interstitial (ELI) content provides exceptional fracture toughness.

• Practical Advice for a Smooth Project:
• Clarify the standard. Chinese drawings often use GB codes (e.g., TC4), while international supply chains use ASTM (e.g., Gr5). Always confirm the equivalence to prevent misunderstandings with your titanium CNC machining supplier.
• TC4 (Gr5) has the most robust supply chain, offers the best relative cost, and has the deepest reservoir of CNC titanium machining experience. Prioritize it when performance requirements allow.
• Properties vary drastically between conditions like “Annealed” and “Solution Treated & Aged.” For example, heat-treated TC4 can be ~20% stronger. Always define this clearly in your technical requirements.
• The β series offers exceptional performance but at a higher cost, with greater challenges in CNC milling titanium and welding. Use them only when the design critically requires it, ideally with expert guidance.

5. Summary

Choosing the correct titanium grade is the foundational step in balancing performance, manufacturability, and cost. Ti-6Al-4V (Grade 5/TC4) remains the universal first choicedue to its unparalleled all-around capabilities.

For applications with extreme demands in corrosion resistance, high temperature, or ultra-high strength, the specialized families of Commercially Pure, high-temperature, or Beta alloys come into play.

Understanding these differences and having a detailed conversation with your titanium CNC machining services provider is the key to your project’s success.

6. FAQ

Q1: What are α-stabilizing elements?

α-stabilizers (like aluminum) increase the temperature at which titanium transforms from α (hexagonal close-packed) to β (body-centered cubic). They enhance strength and heat resistance but may reduce room-temperature ductility.

Q2: What are β-stabilizing elements?

β-stabilizers (like vanadium, molybdenum, chromium, iron) lower the β-phase transformation temperature, enabling heat treatment to adjust strength, toughness, and formability.

Q3: Are TC4 and Grade 5 the same?

Yes, TC4 (China GB/T) corresponds exactly to ASTM Grade 5 (Ti-6Al-4V). Chemically and mechanically identical.

Q4: Is α titanium the same as pure titanium?

Not exactly. Pure titanium (Gr1/Gr2) is α-type, but α alloys can also contain α-stabilizing elements like aluminum.

Q5: Why is Ti-6Al-4V most used in CNC machining?

It offers the best balance of performance, machinability, and cost, with mature cutting strategies, predictable results, and stable supply.

Source: SAE International. (n.d.). AMS4928: Titanium Alloy 6Al – 4V Annealed.