Titanium Ti-3Al-8V-6Cr-4Mo-4Zr-ST (Solution annealed)
Heat-treated state · default condition
UNS R58640 · also 4957
Standard stocked condition: softest, lowest modulus, best cold forming and coiling before aging.
Values for the ST condition
Other Ti-3Al-8V-6Cr-4Mo-4Zr tempers and conditions
Ti-3Al-8V-6Cr-4Mo-4Zr is listed in 5 conditions; see the grade overview at Ti-3Al-8V-6Cr-4Mo-4Zr.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STDefaultThis page Solution annealed | Standard stocked condition: softest, lowest modulus, best cold forming and coiling before aging. | 850 | 900 | 18 | 32 HRC | — |
Solution treated + over-aged (≈565–620 °C) for toughness | Pick when damage tolerance / SCC resistance matters more than peak strength (subsea, deep-well hardware). | 1,060 | 1,130 | 12 | 37 HRC | 1.2 % IACS |
Cold drawn | Wire and small bar for spring coiling: work hardened but still coilable, aged after forming. | 1,080 | 1,150 | 10 | 38 HRC | 1.1 % IACS |
Solution treated and aged | Main high-strength structural condition: ~1200–1400 MPa with deep through-hardening in thick sections. | 1,240 | 1,300 | 8 | 42 HRC | — |
Cold drawn + aged | Highest strength form of Beta C: cold-worked wire aged after coiling for springs and high-strength fasteners. | 1,420 | 1,500 | 5 | 45 HRC | — |
What is Ti-3Al-8V-6Cr-4Mo-4Zr-ST?
Ti-3Al-8V-6Cr-4Mo-4Zr-ST is Ti-3Al-8V-6Cr-4Mo-4Zr heat treated to ST — standard stocked condition: softest, lowest modulus, best cold forming and coiling before aging. Ti-3Al-8V-6Cr-4Mo-4Zr-ST has a yield strength of 850 MPa (123 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of titanium grades. Elongation at break is 18% and the elastic modulus is 86 GPa (12.5 Msi). Ti-3Al-8V-6Cr-4Mo-4Zr-ST has a density of 4.82 g/cm³ (0.174 lb/in³), heavier than 94% of titanium grades. It melts at 1,650°C (3,002 °F).
Advantages
- Tough — resists crack growth — 90 MPa·√m (81.9 ksi·√in), better than 97% of titanium grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 100% of titanium grades
- Low stiffness — 86 GPa (12.5 Msi), worse than 95% of titanium grades
- Difficult to weld — 60/100, worse than 83% of titanium grades
Ti-3Al-8V-6Cr-4Mo-4Zr-ST properties
Typical room-temperature values for Ti-3Al-8V-6Cr-4Mo-4Zr-ST; 14 are specific to this condition. Other listed values are Ti-3Al-8V-6Cr-4Mo-4Zr reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Ti-3Al-8V-6Cr-4Mo-4Zr-ST has a density of 4.82 g/cm³ (0.174 lb/in³), heavier than 94% of titanium grades. It melts at 1,650°C (3,002 °F).
Mechanical15
Ti-3Al-8V-6Cr-4Mo-4Zr-ST has a yield strength of 850 MPa (123 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of titanium grades. Elongation at break is 18% and the elastic modulus is 86 GPa (12.5 Msi).
Thermal6
Ti-3Al-8V-6Cr-4Mo-4Zr-ST is rated for continuous service to 200°C (392 °F). It conducts heat at 7.6 W/m·K (4.39 BTU/hr·ft·°F), worse than 59% of titanium grades. Thermal expansion is 9.4 µm/m·K (5.22 µin/in·°F).
Electrical3
Ti-3Al-8V-6Cr-4Mo-4Zr-ST conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 53% of titanium grades.
Sustainability4
Producing a kilogram of Ti-3Al-8V-6Cr-4Mo-4Zr-ST takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Ti-3Al-8V-6Cr-4Mo-4Zr-ST's machinability is poor (18/100, worse than 83% of titanium grades); weldability good (60/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ti-3Al-8V-6Cr-4Mo-4Zr-ST
Is Ti-3Al-8V-6Cr-4Mo-4Zr easy to machine?
Difficult: use rigid setups, sharp carbide/PVD tooling, low surface speed (~20–35 m/min aged), heavy positive rake and flood high-pressure coolant to avoid work hardening and galling.
Can Ti-3Al-8V-6Cr-4Mo-4Zr be welded?
GTAW/EBW/laser under high-purity inert gas or vacuum with full backside shielding; welds are solution-treated-like and must be re-aged to reach strength — avoid welding in the aged condition.
Can Ti-3Al-8V-6Cr-4Mo-4Zr be formed, bent or molded?
Cold form, coil and bend in the solution-treated condition (allow large springback due to low modulus), then age; hot work in the beta field ~750–870 °C.
What surface finishes work on Ti-3Al-8V-6Cr-4Mo-4Zr?
Pickle/blast to remove alpha case after hot work; accepts color/Type II anodizing (AMS 2488) or passivation; for wear surfaces use nitriding or DLC/hard coatings rather than bare metal.
Ti-3Al-8V-6Cr-4Mo-4Zr chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Al | 3 – 4 | 3.5 |
| V | 7.5 – 8.5 | 8 |
| Cr | 5.5 – 6.5 | 6 |
| Mo | 3.5 – 4.5 | 4 |
| Zr | 3.5 – 4.5 | 4 |
| Fe | ≤ 0.3 | 0.15 |
| O | ≤ 0.14 | 0.1 |
| C | ≤ 0.05 | 0.02 |
| N | ≤ 0.03 | 0.01 |
| Hmax (0.015 typical for bar/billet) | ≤ 0.02 | 0.01 |
| Other, eachresiduals, 0.40 total max | ≤ 0.1 | — |
| Ti | balance | — |
Ti-3Al-8V-6Cr-4Mo-4Zr-ST — frequently asked
What is Ti-3Al-8V-6Cr-4Mo-4Zr-ST used for?
Ti-3Al-8V-6Cr-4Mo-4Zr-ST is typically used for springs, fasteners, subsea cable armor and high-strength aerospace parts. In short: high-hardenability beta titanium; spring and fastener grade; low 86 GPa modulus.
What is the yield strength of Ti-3Al-8V-6Cr-4Mo-4Zr-ST?
Ti-3Al-8V-6Cr-4Mo-4Zr-ST has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 66% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is Ti-3Al-8V-6Cr-4Mo-4Zr-ST easy to machine?
Not especially — machinability is rated poor (18/100, worse than 83% of titanium grades). Difficult: use rigid setups, sharp carbide/PVD tooling, low surface speed (~20–35 m/min aged), heavy positive rake and flood high-pressure coolant to avoid work hardening and galling.
Can Ti-3Al-8V-6Cr-4Mo-4Zr-ST be welded?
Yes — weldability is rated good (60/100). GTAW/EBW/laser under high-purity inert gas or vacuum with full backside shielding; welds are solution-treated-like and must be re-aged to reach strength — avoid welding in the aged condition.
What surface finishes work on Ti-3Al-8V-6Cr-4Mo-4Zr-ST?
Pickle/blast to remove alpha case after hot work; accepts color/Type II anodizing (AMS 2488) or passivation; for wear surfaces use nitriding or DLC/hard coatings rather than bare metal.
Can Ti-3Al-8V-6Cr-4Mo-4Zr-ST be formed, bent or molded?
Cold form, coil and bend in the solution-treated condition (allow large springback due to low modulus), then age; hot work in the beta field ~750–870 °C.
What is the maximum service temperature of Ti-3Al-8V-6Cr-4Mo-4Zr-ST?
Ti-3Al-8V-6Cr-4Mo-4Zr-ST is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti-3Al-8V-6Cr-4Mo-4Zr-ST and Ti-3Al-8V-6Cr-4Mo-4Zr-CDA?
ST is the default condition — standard stocked condition: softest, lowest modulus, best cold forming and coiling before aging. CDA: highest strength form of Beta C: cold-worked wire aged after coiling for springs and high-strength fasteners. Yield strength is 850 MPa in ST versus 1,420 MPa in CDA.
Sources
- ASTM B348 / B863 — Titanium and Titanium Alloy Bars and Wire (Grade 19, UNS R58640) — ASTM (2021)
- AMS 4957 / AMS 4958 — Titanium Alloy Wire 3Al-8V-6Cr-4Mo-4Zr — SAE International (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- Beta C (Ti-3Al-8V-6Cr-4Mo-4Zr) alloy datasheet — RTI/TIMET (titanium producers) (2016)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.