Titanium C-4-ANN (Annealed)
Heat-treated state
ASTM B367 Grade C-4
Choose for maximum ductility, dimensional stability and lowest hardness before heavy machining or forming of thin sections.
Values for the ANN condition
Other C-4 tempers and conditions
C-4 is listed in 5 conditions; see the grade overview at C-4.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Choose for maximum ductility, dimensional stability and lowest hardness before heavy machining or forming of thin sections. | 500 | 590 | 15 | 24 HRC | — |
hot isostatically pressed then vacuum annealed | Highest-integrity condition for critical aerospace/medical or high-cycle-fatigue castings needing both pore closure and full stress relief. | 510 | 600 | 17 | 250 HB | — |
Stress relieved | Pick when casting/weld-repair residual stresses must be removed before final machining, with no strength loss. | 520 | 615 | 13 | 25 HRC | 2.9 % IACS |
Hot isostatic pressed | Specify for pressure-containing or fatigue-loaded castings: closes internal gas/shrinkage porosity and lifts ductility and fatigue life. | 525 | 620 | 16 | 260 HB | — |
FDefault As fabricated | Standard supply condition for general corrosion-service castings where B367 minimums are sufficient. | 530 | 620 | 12 | 26 HRC | — |
What is C-4-ANN?
C-4-ANN is C-4 heat treated to ANN — choose for maximum ductility, dimensional stability and lowest hardness before heavy machining or forming of thin sections. C-4-ANN has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — weaker than 62% of titanium grades. Elongation at break is 15% and the elastic modulus is 104 GPa (15.1 Msi). C-4-ANN has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,660°C (3,020 °F). F is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- Conducts heat well — 17.2 W/m·K (9.94 BTU/hr·ft·°F), better than 88% of titanium grades
Limitations
- Limited formability — 20/100, worse than 83% of titanium grades
C-4-ANN properties
Typical room-temperature values for C-4-ANN; 11 are specific to this condition. Other listed values are C-4 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
C-4-ANN has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,660°C (3,020 °F).
Mechanical16
C-4-ANN has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — weaker than 62% of titanium grades. Elongation at break is 15% and the elastic modulus is 104 GPa (15.1 Msi).
Thermal6
C-4-ANN is rated for continuous service to 300°C (572 °F). It conducts heat at 17.2 W/m·K (9.94 BTU/hr·ft·°F), better than 88% of titanium grades. Thermal expansion is 8.6 µm/m·K (4.78 µin/in·°F).
Electrical3
C-4-ANN conducts electricity at 2.9 % IACS, better than 58% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 53% of titanium grades.
Sustainability4
Producing a kilogram of C-4-ANN takes about 650 MJ of energy and emits 39 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 25%.
Manufacturability8
C-4-ANN's machinability is poor (34/100, better than 74% of titanium grades); weldability excellent (85/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C-4-ANN
Is C-4 easy to machine?
Machine at low surface speed (20–40 m/min) with sharp, positive-rake uncoated carbide, heavy rigid setup and flood coolant; remove the oxygen-rich α-case by chemical milling before finish cuts and never let the tool dwell (galling/fire risk in fine chips).
Can C-4 be welded?
Very good GTAW/EBW/plasma weldability with matching CP-Ti filler (ERTi-4) — but requires full argon/helium shielding of pool, root and hot metal below 425 °C; a bright silver bead colour is the acceptance criterion.
Can C-4 be formed, bent or molded?
Vacuum-arc or induction skull melted and poured into rammed graphite or yttria/zirconia face-coated investment shells; allow ~1 % shrink, generous fillets and thick risers, then chem-mill 0.2–0.5 mm α-case and HIP for pressure duty.
What surface finishes work on C-4?
Pickle in HNO₃/HF to remove scale and α-case, then anodize (AMS 2488 Type II colour or Type III wear-resistant oxide); grit blasting must use clean alumina, and iron contamination from steel tooling must be avoided to preserve corrosion resistance.
C-4 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 |
|---|---|---|
| N | ≤ 0.05 | 0.02 |
| C | ≤ 0.1 | 0.03 |
| Hmax, on cast product | ≤ 0.02 | 0.01 |
| Fe | ≤ 0.5 | 0.3 |
| Omax — controls the strength level of C-4 | ≤ 0.4 | 0.33 |
| Residuals (each)per ASTM B367 | ≤ 0.1 | — |
| Residuals (total)per ASTM B367 | ≤ 0.4 | — |
| Ti | balance | — |
C-4-ANN — frequently asked
What is C-4-ANN used for?
C-4-ANN is typically used for high-strength valve trim, structural brackets, marine/offshore fittings and medical instrument castings. In short: strongest unalloyed cast titanium; cast CP Grade 4 equivalent; strength without alloying additions.
What is the yield strength of C-4-ANN?
C-4-ANN has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 590 MPa (85.6 ksi) — weaker than 62% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is C-4-ANN easy to machine?
Not especially — machinability is rated poor (34/100, better than 74% of titanium grades). Machine at low surface speed (20–40 m/min) with sharp, positive-rake uncoated carbide, heavy rigid setup and flood coolant; remove the oxygen-rich α-case by chemical milling before finish cuts and never let the tool dwell (galling/fire risk in fine chips).
Can C-4-ANN be welded?
Yes — weldability is rated excellent (85/100). Very good GTAW/EBW/plasma weldability with matching CP-Ti filler (ERTi-4) — but requires full argon/helium shielding of pool, root and hot metal below 425 °C; a bright silver bead colour is the acceptance criterion.
What surface finishes work on C-4-ANN?
Pickle in HNO₃/HF to remove scale and α-case, then anodize (AMS 2488 Type II colour or Type III wear-resistant oxide); grit blasting must use clean alumina, and iron contamination from steel tooling must be avoided to preserve corrosion resistance.
Can C-4-ANN be formed, bent or molded?
Vacuum-arc or induction skull melted and poured into rammed graphite or yttria/zirconia face-coated investment shells; allow ~1 % shrink, generous fillets and thick risers, then chem-mill 0.2–0.5 mm α-case and HIP for pressure duty.
What is the maximum service temperature of C-4-ANN?
C-4-ANN 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-4-F and C-4-ANN?
F is the default condition — standard supply condition for general corrosion-service castings where B367 minimums are sufficient. ANN: choose for maximum ductility, dimensional stability and lowest hardness before heavy machining or forming of thin sections. Yield strength is 530 MPa in F versus 500 MPa in ANN.
Sources
- ASTM B367 Standard Specification for Titanium and Titanium Alloy Castings — ASTM International (2022)
- ASTM B265 / ASTM F67 (wrought CP-Ti Grade 4 reference properties) — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- ASM Handbook Vol. 13B — Corrosion: Materials (Titanium) — ASM International (2005)
- GB/T 15073 / GB/T 6614 — SAC (2014)
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.