Titanium C-4
ASTM B367 Grade C-4
C-4 is the highest-strength unalloyed titanium casting grade in ASTM B367, the cast analog of wrought CP Grade 4, relying on controlled oxygen rather than alloying additions.
Reference datasheet — C-4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the F condition
C-4 tempers and conditions
C-4 is supplied in 5 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
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?
C-4 is the highest-strength unalloyed titanium casting grade in ASTM B367, the cast analog of wrought CP Grade 4, relying on controlled oxygen rather than alloying additions. It provides 530 MPa yield, 620 MPa tensile, 12 % elongation and 265 HB (26 HRC) with service to 300 °C, and is poured as valve trim, brackets and offshore fittings that need moderate strength with full CP corrosion resistance. Ductility and machinability (score 30) are lower than C-1 or C-2, castings need alpha-case removal and usually HIP for pressure duty, and Ti-6Al-4V castings remain the option when higher strength is required. C-4 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). C-4 has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 59% of titanium grades. Elongation at break is 12% and the elastic modulus is 104 GPa (15.1 Msi).
What is C-4 used for?
- high-strength valve trim
- structural brackets
- marine/offshore fittings
- medical instrument castings
Advantages
- Conducts heat well — 17.2 W/m·K (9.94 BTU/hr·ft·°F), better than 88% of titanium grades
Limitations
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 83% of titanium grades
- Limited formability — 20/100, worse than 83% of titanium grades
- Limited ductility — 12%, worse than 78% of titanium grades
C-4 properties
Typical room-temperature values for C-4-F; bars are the position among titanium grades.
Physical3
C-4 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 has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 59% of titanium grades. Elongation at break is 12% and the elastic modulus is 104 GPa (15.1 Msi).
Thermal6
C-4 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 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 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's machinability is poor (30/100, better than 64% of titanium grades); weldability excellent (85/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the titanium family
Yield strength against density for every titanium grade FabDigit runs. C-4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C-4
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.
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 |
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.
Surface treatments FabDigit runs on titanium parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Titanium C-4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B367 Grade C-4
How much does C-4 cost?
C-4 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C-4 — frequently asked
What is C-4 used for?
C-4 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?
C-4 has a typical yield strength of 530 MPa (76.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 59% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is C-4 easy to machine?
Not especially — machinability is rated poor (30/100, better than 64% 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 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?
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 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?
C-4 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.
How much does C-4 cost?
C-4 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.