GR5 (Ti-6Al-4V) bar and billet are the mill forms most titanium machined parts and forgings start from. You buy them against one of two documents: ASTM B348 for general industrial use, or AMS 4928 when the part is aerospace and needs tighter process control plus ultrasonic inspection. Both describe the same UNS R56400 alloy — what changes is the specification envelope, not the metal.
Bar vs Billet: What You Are Actually Ordering
- Bar — hot-rolled or forged stock, then turned, peeled or ground, in round, square or hexagonal section. The direct input for CNC turning and milling.
- Billet — larger-section semi-finished forging stock, made to be re-forged. Internal soundness matters far more than dimensional precision.
- Rule of thumb — machined part on the drawing, order bar; press or hammer first, order billet.
ASTM B348 or AMS 4928? How the Standards Differ
| Item | ASTM B348 | AMS 4928 |
|---|---|---|
| Scope | Industrial bar and billet | Aerospace bar, wire, forgings, rings |
| Chemistry | Grade 5 limits, Al / V / interstitials | Same alloy, tighter residuals |
| Process control | Mill practice on the test report | Thermomechanical history traceable to lot |
| Ultrasonic testing | Only if ordered | Built into the specification |
| Typical use | Valves, pumps, marine hardware | Aircraft structures, fasteners, forgings |
The aerospace document is not simply “stricter” — it moves requirements into areas B348 leaves to the purchase order. Dual-certified bar covering both is common and usually the most economical route for a mixed order book.
Chemistry and Typical Mechanical Properties
Ti-6Al-4V is 6% aluminium and 4% vanadium, balanced titanium, with iron and oxygen as the interstitial drivers. Per the standard, aluminium sits around 5.5–6.75%, vanadium 3.5–4.5%, iron 0.30% max and oxygen 0.20% max for Grade 5; ELI material tightens oxygen and iron. Confirm actual values on the mill test report.
| Condition | Typical tensile | Typical yield | Elongation | Choose when |
|---|---|---|---|---|
| Annealed | 895 MPa min | 828 MPa min | 10% min | Default for machining |
| Solution treated + aged | ~1,100 MPa (ref.) | ~1,000 MPa (ref.) | Lower | High-strength parts |
| Duplex annealed | Intermediate | Intermediate | Moderate | Damage tolerance |
| Beta annealed | Reference only | Reference only | Lowest | Toughness-driven forging stock |
These are typical or per-standard values, not a guaranteed specification — section size, test location and heat treat all move them, so name the condition on the order.
Finishes, Tolerances and Alpha Case
Hot working leaves a thin oxygen-enriched alpha case that is hard and brittle. It must be removed before fatigue-critical use; depth depends on temperature and time, not a fixed rule, so state whether removal must be verified.
- As-rolled / as-forged — cheapest, largest machining allowance, alpha case present.
- Turned or peeled — scale and alpha case removed, suitable for most machining.
- Centerless ground — tight diameter and straightness, preferred for bar-fed lathes.
- Polished — visible parts and surface-integrity inspection.
What to Put in the RFQ
- Grade and UNS — GR5 / UNS R56400, or Grade 23 if ELI is required.
- Specification — ASTM B348, AMS 4928, or both.
- Condition — annealed, STA, duplex or beta annealed.
- Form and size — bar or billet, section, diameter, tolerance class, length.
- Surface — as-supplied, turned, ground or polished, alpha case verification.
- Inspection and documents — ultrasonic level, PMI on arrival, EN 10204 3.1 report with heat number.
Inspection: Where GR5 Orders Actually Go Wrong
For GR5 the risk is rarely the alloy — it is lot-to-lot variation in interstitial content and heat treatment, both of which decide whether your machining and downstream heat-treat plans hold. A practical incoming package is the 3.1 mill test report tied to the heat number, hardness and dimensional checks, and ultrasonic testing where the application calls for it. Positive material identification on arrival closes the loop on grade mix-ups, a real risk when GR5, GR9 and GR2 bar share a warehouse. If you are still choosing between grades, see our GR5 (Ti-6Al-4V) workhorse alloy guide; the titanium bar and rod overview lists the forms and standards we handle.
Sourcing Ti-6Al-4V Bar and Billet Through FDtitanium
As an integrated titanium supplier we pass your specification through to qualified production rather than paraphrasing it — the grade, condition and standard on your PO are the ones printed on the test report. We handle incoming chemistry and dimensional verification, EN 10204 3.1 documentation on every lot, ultrasonic and PMI arrangements where needed, MOQs from prototype quantities to production releases, and one accountable contact from enquiry to delivery. Where a drawing is ambiguous we raise it before material is cut.
Frequently Asked Questions
Is Ti-6Al-4V bar the same as Grade 5 bar?
Yes. Ti-6Al-4V, Grade 5 and UNS R56400 are the same alloy — chemistry name, ASTM grade number and UNS code for one material.
Should I order ASTM B348 or AMS 4928?
Use AMS 4928 only when your drawing or customer requires aerospace release, since it adds process control and ultrasonic requirements that raise cost. For valves, pumps and general machining, ASTM B348 is normally sufficient.
Can Ti-6Al-4V bar be supplied in the STA condition?
Yes, at typical reference strengths around 1,100 MPa with lower ductility than annealed. Heat-treat response depends on section size, so confirm condition and acceptance values against your drawing and RFQ.
Does Grade 23 bar differ from Grade 5?
Grade 23 is Ti-6Al-4V ELI with tighter oxygen and iron limits, giving better fracture toughness and fatigue behaviour. It is the usual choice for implants and cryogenic service, at higher cost.
Get a Quote for Ti-6Al-4V Bar and Billet
Send grade, specification, condition, sizes and inspection requirements to FDtitanium and we will return a graded offer with mill test report scope, tolerance class and lead time stated up front.
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