Ti-6Al-4V CNC Machining - Grade 5 Titanium
Ti-6Al-4V is the titanium alloy. More than half of all titanium produced globally goes into this single alloy, and most of that ends up in aerospace structures, engine components, and defense hardware. Its combination of high strength, low density, excellent corrosion resistance, and proven aerospace qualification history makes it the default titanium specification for structural flight hardware.
Carr Machine & Tool machines Ti-6Al-4V for aerospace, defense, and space customers from Elk Grove Village, Illinois. We produce structural brackets, housings, fittings, manifolds, shafts, and complex multi-feature components in Ti-6Al-4V with 5-axis milling, material-specific process planning, AS9100D-certified documentation, and CMM inspection.
Ti-6Al-4V Material Properties and Why They Drive Machining Decisions
Ti-6Al-4V is an alpha-beta titanium alloy. Its mechanical properties are set by a combination of chemistry and heat treatment condition, and the specific condition on your drawing determines how we approach the job.
The low thermal conductivity is the property that most directly drives machining cost. Heat that would distribute through the workpiece in steel stays concentrated at the cutting edge in titanium, accelerating tool wear, causing built-up edge, and, in shops without material-specific process planning, producing dimensional drift and poor surface finish.
| Property | Ti-6Al-4V (Annealed) | Ti-6Al-4V (STA) | Comparison |
|---|---|---|---|
| Tensile Strength | ∼130 ksi | ∼170 ksi | Higher than most structural aluminums |
| Yield Strength | ∼120 ksi | ∼160 ksi | — |
| Density | 0.160 lb/in³ | 0.160 lb/in³ | ∼57% of steel density |
| Thermal Conductivity | 6.7 W/m·K | 6.7 W/m·K | Low — heat concentrates at tool |
| Elastic Modulus | ∼16.5 Msi | ∼16.5 Msi | About half of steel |
HEAT TREATMENT CONDITIONS FOR TI-6AL-4V
We machine Ti-6Al-4V in the following conditions:
- Mill Annealed (MA): The as-delivered condition for most bar and plate. Lowest strength, best machinability within the Ti-6Al-4V family. Most structural aerospace components are machined in this condition.
- Duplex Annealed (DA): Used where optimized fatigue resistance is needed. Properties fall between annealed and STA.
- Solution Treated and Aged (STA): Maximum strength condition. Yield strength up to 160 ksi. Significantly harder to machine than annealed — requires adjusted tooling and parameters. Often more economical to machine before aging and then age the machined part, depending on geometry.
- Hot Isostatic Pressed (HIP): Applied to castings and powder metallurgy forms. We machine HIP’d Ti-6Al-4V where casting porosity has been closed and the part requires final machined features.
Ti-6Al-4V MACHINING CAPABILITIES & PROCESS APPROACH
- 5-Axis Milling of Complex Ti-6Al-4V Components: The structural fittings, brackets, and housings that dominate Ti-6Al-4V programs frequently involve compound angles, multi-surface features, deep pockets, and thin walls. Our 5-axis milling allows us to complete these features in fewer setups. In titanium specifically, fewer setups mean fewer interrupted cuts, which is important because restarting a cut on a titanium surface generates localized heat and stress that can affect the subsequent finish cut.
- Lights-Out Machining for Ti-6Al-4V Production: Ti-6Al-4V has long cycle times relative to aluminum. A complex fitting that runs in 20 minutes in 6061 may run in 60–90 minutes in Ti-6Al-4V. Our lights-out machining capability means that cycle time does not compress lead time, as the machine runs through the night and your parts advance regardless of shift schedule.
- Tooling Strategy and Change Management: We track tool life in titanium production and change cutting tools proactively – before wear reaches a level that could affect dimensional output. Tool life management is built into the process plan for every Ti-6Al-4V program. We do not run tools to failure on aerospace parts.
- Coolant Strategy: Flood coolant at appropriate pressure and volume is required for titanium machining to prevent thermal damage at the cutting zone. Our machines are equipped for high-pressure coolant delivery, and our programmers specify coolant strategy as part of the process plan, not as an afterthought.
AMS Specifications for Ti-6Al-4V
Ti-6Al-4V is procured and processed to a range of AMS specifications depending on product form and condition.
We source Ti-6Al-4V to the specification called out on your drawing. If your drawing references a customer-specific spec that maps to an AMS spec, note this in your RFQ and we will confirm material sourcing alignment.
| AMS Spec | Product Form |
|---|---|
| AMS 4928 | Bar, billet, rings — annealed |
| AMS 4965 | Bar, billet — solution treated and aged |
| AMS 4911 | Sheet and plate — annealed |
| AMS 4920 | Sheet and plate — annealed (alternate) |
| AMS 2631 | Ultrasonic inspection of titanium products |
| AMS 2801 | Heat treatment of titanium |
Common Ti-6Al-4V Components We Machine
- Primary Structural Brackets: Airframe attachment hardware, spar fittings, and load-path-critical structure
- Engine Mounts and Nacelle Hardware: High-load structural fittings in the engine attachment zone
- Landing Gear Structural Components: Drag struts, torque links, and structural fittings requiring both strength and impact toughness
- Flight Control Hardware: Bellcranks, actuator brackets, and push-pull rod end fittings
- Propulsion System Hardware: Manifolds, valve bodies, and pressure hardware for aerospace propulsion
- Space Structural Components: Adapter rings, strut end fittings, and mounting hardware for satellite and launch vehicle programs
- Defense Structural Hardware: Weapon system housings, sensor mounts, and structural fittings for ground and airborne defense systems
Integrated Quality and Documentation
Material Traceability to Heat and Lot: Every Ti-6Al-4V job is run from stock with a documented mill certificate covering chemistry and mechanical properties. The heat and lot number is tied to your job traveler and retained in our records. This traceability is maintained from raw stock receipt through shipment of finished parts.
First Article Inspection Reports: New Ti-6Al-4V programs receive complete FAIRs with balloon drawings and actual measured values for every print callout. FAIRs are formatted to your program requirements, like AS9100D, AS9102, or customer-specific formats, and are provided with the first shipment.
CMM Dimensional Verification: Critical dimensions and GD&T callouts on Ti-6Al-4V components are verified with CMM inspection. CMM reports document actual values, nominal values, and tolerance bands for every controlled feature. We include CMM reports with shipments on programs where dimensional documentation is required.
Surface Finish Verification: Surface finish callouts on Ti-6Al-4V aerospace parts are verified with profilometer measurement and documented in our inspection records. Fatigue-life-critical surfaces receive particular attention during the finishing process and inspection.
FREQUENTLY ASKED QUESTIONS
What makes Ti-6Al-4V so widely used in aerospace?
The combination of high specific strength (strength divided by density), excellent corrosion resistance, good fatigue performance, and a long flight heritage in aerospace qualification databases makes Ti-6Al-4V the default titanium specification for aerospace structural applications. There are stronger titanium alloys and lighter ones, but Ti-6Al-4V hits the intersection of properties, qualification data, and material availability that makes it the standard choice for new aerospace programs.
Should I machine Ti-6Al-4V before or after heat treatment?
In most cases, Ti-6Al-4V structural components are machined from annealed stock and used in that condition. For STA applications requiring higher strength, the component can either be machined before aging (then aged to final condition) or machined in the aged condition. Machining before aging is generally more economical since annealed Ti-6Al-4V machines more efficiently than aged. However, part geometry and distortion risk during aging need to be evaluated. We can discuss the trade-off for your specific program during quoting.
What AMS spec should I call out for Ti-6Al-4V bar stock?
For annealed bar and billet, AMS 4928 is the standard specification. For solution-treated and aged bar, AMS 4965 applies. If your drawing already specifies an AMS number, we source to that spec. If you are writing a new drawing and need guidance, our team can recommend the appropriate specification for your application during the design review process.
Can you machine Ti-6Al-4V for ITAR-controlled programs?
Yes. We are registered with the DDTC under ITAR and can accept ITAR-controlled drawings and technical data for Ti-6Al-4V machining programs. Our access controls and personnel management operate within ITAR compliance requirements.
Do you have experience with thin-wall Ti-6Al-4V structures?
Yes. Thin-wall and lightweight Ti-6Al-4V structures — common in satellite hardware and aerospace weight-critical components — require fixture design, toolpath sequencing, and in-process inspection to maintain conformance. We identify thin-wall features during the quoting process and build appropriate process controls into the job plan before the first part runs.
What surface finish can you achieve on Ti-6Al-4V?
As-machined Ra 63 µin is typical for roughed surfaces. Semi-finish and finish passes achieve Ra 32 µin routinely. For fatigue-sensitive surfaces, Ra 16 µin or finer is achievable with appropriate tooling and finishing pass planning. Surface finish is verified with profilometer measurement where your drawing specifies a callout.
Partner with CARR Machine & Tool
Submit your Ti-6Al-4V drawing with quantity, heat treat condition, AMS specification, and delivery requirement. We will review the geometry, assess any process-level considerations, and return a complete quote with lead time and DFM notes.
