Titanium ZTC4 Annealed
Temper · default condition
UNS R56406
Standard commercial delivery condition for ZTC4 castings: residual stresses removed, alpha-case chem-milled, balanced strength/ductility.
Values for the Annealed condition
Other ZTC4 tempers and conditions
ZTC4 is listed in 5 conditions; see the grade overview at ZTC4.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Cheapest condition for non-critical corrosion or general engineering castings where GB/T 6614 minimum properties suffice. | 820 | 890 | 6 | 34 HRC | — |
AnnealedDefaultThis page vacuum stress-relief/anneal ~700–800 °C, chemically milled | Standard commercial delivery condition for ZTC4 castings: residual stresses removed, alpha-case chem-milled, balanced strength/ductility. | 840 | 910 | 8 | 35 HRC | — |
HIP + Annealed | Aerospace/medical standard route: porosity closed and structure/stresses stabilised for best fatigue and toughness consistency. | 850 | 925 | 12 | 34 HRC | — |
Hot isostatic pressed | Pick when internal gas/shrink porosity must be closed for fatigue-critical or aerospace/medical castings. | 855 | 930 | 11 | 35 HRC | — |
Solution treated and aged | Choose for maximum strength/hardness in thinner cast sections, accepting reduced ductility and toughness. | 930 | 1,020 | 6 | 38 HRC | — |
What is ZTC4 Annealed?
ZTC4 Annealed is ZTC4 in the Annealed temper — standard commercial delivery condition for ZTC4 castings: residual stresses removed, alpha-case chem-milled, balanced strength/ductility. ZTC4 Annealed has a yield strength of 840 MPa (122 ksi) and a tensile strength of 910 MPa (132 ksi) — stronger than 63% of titanium grades. Elongation at break is 8% and the elastic modulus is 110 GPa (16 Msi). ZTC4 Annealed has a density of 4.43 g/cm³ (0.16 lb/in³), lighter than 89% of titanium grades. It melts at 1,604°C (2,919 °F).
Limitations
- Limited ductility — 8%, worse than 99% of titanium grades
- Limited formability — 10/100, worse than 99% of titanium grades
- Low electrical conductivity — 1 % IACS, worse than 89% of titanium grades
ZTC4 Annealed properties
Typical room-temperature values for ZTC4 Annealed; 12 are specific to this condition. Other listed values are ZTC4 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
ZTC4 Annealed has a density of 4.43 g/cm³ (0.16 lb/in³), lighter than 89% of titanium grades. It melts at 1,604°C (2,919 °F).
Mechanical16
ZTC4 Annealed has a yield strength of 840 MPa (122 ksi) and a tensile strength of 910 MPa (132 ksi) — stronger than 63% of titanium grades. Elongation at break is 8% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
ZTC4 Annealed is rated for continuous service to 350°C (662 °F). It conducts heat at 7 W/m·K (4.04 BTU/hr·ft·°F), worse than 76% of titanium grades. Thermal expansion is 8.8 µm/m·K (4.89 µin/in·°F).
Electrical3
ZTC4 Annealed conducts electricity at 1 % IACS, worse than 89% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), worse than 77% of titanium grades.
Sustainability4
Producing a kilogram of ZTC4 Annealed takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability8
ZTC4 Annealed's machinability is poor (18/100, worse than 83% of titanium grades); weldability very good (75/100); 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 ZTC4 Annealed
Is ZTC4 easy to machine?
Machine like wrought Ti-6Al-4V but remove the hard alpha-case/reaction layer first (chem-mill) — low surface speed (~25–45 m/min carbide), heavy positive-rake sharp tools, high-pressure flood coolant, never dwell in cut.
Can ZTC4 be welded?
GTAW/EBW/plasma weld repair with ERTi-5 filler is routine and standard for castings, but must be done in high-purity argon chambers or vacuum with clean, hydride-free surfaces followed by stress-relief anneal.
Can ZTC4 be formed, bent or molded?
Vacuum-arc-melted metal poured into ceramic-shell investment or rammed-graphite moulds; needs ~1.5–2 % pattern shrink allowance, generous fillets, and HIP for porosity-sensitive parts.
What surface finishes work on ZTC4?
Grit-blast plus HF/HNO3 chemical milling to strip alpha-case; then optional Type II anodise (AMS 2488) for galling resistance, passivation, or mechanical/electro-polish; avoid Cd/Cl-bearing marking and cleaning agents.
ZTC4 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 |
|---|---|---|
| Alalpha stabiliser | 5.5 – 6.75 | 6.1 |
| Vbeta stabiliser | 3.5 – 4.5 | 4 |
| Fe | ≤ 0.3 | 0.12 |
| Si | ≤ 0.15 | 0.05 |
| C | ≤ 0.1 | 0.03 |
| N | ≤ 0.05 | 0.02 |
| H | ≤ 0.02 | 0.01 |
| Ohigher than wrought TC4; controls strength/ductility | ≤ 0.2 | 0.14 |
| Other, each | ≤ 0.1 | — |
| Other, total | ≤ 0.4 | — |
| Ti | balance | — |
ZTC4 Annealed — frequently asked
What is ZTC4 Annealed used for?
ZTC4 Annealed is typically used for aerospace structural castings, pump/valve bodies, impellers and biomedical implant castings. In short: workhorse cast Ti-6Al-4V; high strength, low machinability; wide foundry availability.
What is the yield strength of ZTC4 Annealed?
ZTC4 Annealed has a typical yield strength of 840 MPa (122 ksi) and a tensile strength of 910 MPa (132 ksi) — stronger than 63% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is ZTC4 Annealed easy to machine?
Not especially — machinability is rated poor (18/100, worse than 83% of titanium grades). Machine like wrought Ti-6Al-4V but remove the hard alpha-case/reaction layer first (chem-mill) — low surface speed (~25–45 m/min carbide), heavy positive-rake sharp tools, high-pressure flood coolant, never dwell in cut.
Can ZTC4 Annealed be welded?
Yes — weldability is rated very good (75/100). GTAW/EBW/plasma weld repair with ERTi-5 filler is routine and standard for castings, but must be done in high-purity argon chambers or vacuum with clean, hydride-free surfaces followed by stress-relief anneal.
What surface finishes work on ZTC4 Annealed?
Grit-blast plus HF/HNO3 chemical milling to strip alpha-case; then optional Type II anodise (AMS 2488) for galling resistance, passivation, or mechanical/electro-polish; avoid Cd/Cl-bearing marking and cleaning agents.
Can ZTC4 Annealed be formed, bent or molded?
Vacuum-arc-melted metal poured into ceramic-shell investment or rammed-graphite moulds; needs ~1.5–2 % pattern shrink allowance, generous fillets, and HIP for porosity-sensitive parts.
What is the maximum service temperature of ZTC4 Annealed?
ZTC4 Annealed is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZTC4 Annealed and ZTC4-STA?
Annealed is the default condition — standard commercial delivery condition for ZTC4 castings: residual stresses removed, alpha-case chem-milled, balanced strength/ductility. STA: choose for maximum strength/hardness in thinner cast sections, accepting reduced ductility and toughness. Yield strength is 840 MPa in Annealed versus 930 MPa in STA.
Sources
- ASTM B367 Standard Specification for Titanium and Titanium Alloy Castings (Grade C-5 / R56406) — ASTM International (2022)
- ASM Specialty Handbook: Titanium and Titanium Alloys — ASM International (1994)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (titanium) — 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.