Titanium C-9-A (Solution annealed)
Temper · default condition
ASTM B367 Grade C-9
Standard stocked condition: annealing relieves casting stresses and stabilises properties for ASTM B367 acceptance testing.
Values for the A condition
Other C-9 tempers and conditions
C-9 is listed in 5 conditions; see the grade overview at C-9.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Lowest-cost condition for non-critical corrosion-service castings where internal porosity is acceptable. | 540 | 670 | 10 | 23 HRC | 1.4 % IACS |
Stress relieved | Pick when weld-repaired or heavily machined castings need distortion control without a full anneal. | 545 | 680 | 11 | 23 HRC | 1.4 % IACS |
ADefaultThis page Solution annealed | Standard stocked condition: annealing relieves casting stresses and stabilises properties for ASTM B367 acceptance testing. | 550 | 690 | 12 | 23 HRC | — |
Hot isostatically pressed then annealed | Aerospace/medical practice: densification plus a stabilising anneal for the most uniform and reproducible properties. | 555 | 695 | 15 | 21 HRC | 1.4 % IACS |
Hot isostatic pressed | Choose for fatigue- or fracture-critical castings: HIP closes internal porosity and roughly doubles fatigue scatter-band floor. | 560 | 700 | 14 | 22 HRC | 1.4 % IACS |
What is C-9-A?
C-9-A is C-9 in the A temper — standard stocked condition: annealing relieves casting stresses and stabilises properties for ASTM B367 acceptance testing. C-9-A has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 55% of titanium grades. Elongation at break is 12% and the elastic modulus is 100 GPa (14.5 Msi). C-9-A has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,650°C (3,002 °F).
Limitations
- Limited formability — 10/100, worse than 99% of titanium grades
- Limited ductility — 12%, worse than 78% of titanium grades
C-9-A properties
Typical room-temperature values for C-9-A; 12 are specific to this condition. Other listed values are C-9 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
C-9-A has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,650°C (3,002 °F).
Mechanical16
C-9-A has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 55% of titanium grades. Elongation at break is 12% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
C-9-A is rated for continuous service to 300°C (572 °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
C-9-A conducts electricity at 1.4 % IACS, better than 53% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 53% of titanium grades.
Sustainability4
Producing a kilogram of C-9-A takes about 650 MJ of energy and emits 42 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 35%.
Manufacturability8
C-9-A's machinability is poor (25/100, better than 53% of titanium grades); weldability very good (80/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C-9-A
Is C-9 easy to machine?
Low speed, high feed, rigid setup, flood coolant and sharp carbide/PVD tooling; alpha-case from casting must be chemically milled or ground off before finish machining.
Can C-9 be welded?
GTAW/EBW with full argon or vacuum shielding welds well and is the standard casting repair route; keep interstitials low and post-weld stress relieve.
Can C-9 be formed, bent or molded?
Investment or rammed-graphite casting under vacuum/argon in a skull or induction furnace; allow ~1.5–2 % shrink and generous fillets to avoid hot tearing.
What surface finishes work on C-9?
Chemical milling of alpha case, bead blast or tumble finish; colour or Type II anodizing per AMS 2488 for identification and galling resistance; plating rarely used.
C-9 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 | 2.5 – 3.5 | 3 |
| V | 2 – 3 | 2.5 |
| Fe | ≤ 0.25 | 0.15 |
| O | ≤ 0.15 | 0.12 |
| C | ≤ 0.08 | 0.03 |
| N | ≤ 0.05 | 0.02 |
| H | ≤ 0.02 | 0.01 |
| Residuals eachmax, each | ≤ 0.1 | — |
| Residuals totalmax, total | ≤ 0.4 | — |
| Ti | balance | — |
C-9-A — frequently asked
What is C-9-A used for?
C-9-A is typically used for aerospace fittings, hydraulic tubing components and medium-strength structural castings. In short: weldable mid-strength cast titanium; cast Ti-3Al-2.5V counterpart; strong corrosion resistance.
What is the yield strength of C-9-A?
C-9-A has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 55% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is C-9-A easy to machine?
Not especially — machinability is rated poor (25/100, better than 53% of titanium grades). Low speed, high feed, rigid setup, flood coolant and sharp carbide/PVD tooling; alpha-case from casting must be chemically milled or ground off before finish machining.
Can C-9-A be welded?
Yes — weldability is rated very good (80/100). GTAW/EBW with full argon or vacuum shielding welds well and is the standard casting repair route; keep interstitials low and post-weld stress relieve.
What surface finishes work on C-9-A?
Chemical milling of alpha case, bead blast or tumble finish; colour or Type II anodizing per AMS 2488 for identification and galling resistance; plating rarely used.
Can C-9-A be formed, bent or molded?
Investment or rammed-graphite casting under vacuum/argon in a skull or induction furnace; allow ~1.5–2 % shrink and generous fillets to avoid hot tearing.
What is the maximum service temperature of C-9-A?
C-9-A is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C-9-A and C-9-F?
A is the default condition — standard stocked condition: annealing relieves casting stresses and stabilises properties for ASTM B367 acceptance testing. F: lowest-cost condition for non-critical corrosion-service castings where internal porosity is acceptable. Yield strength is 550 MPa in A versus 540 MPa in F.
Sources
- ASTM B367 Standard Specification for Titanium and Titanium Alloy Castings — ASTM International (2022)
- ASTM B265 / ASTM B338 (wrought Grade 9 Ti-3Al-2.5V property basis) — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
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.