Titanium ZTC4
UNS R56406
ZTC4 (UNS R56406) is the GB national-standard designation for cast Ti-6Al-4V, the cast counterpart of wrought TC4 and the workhorse alpha-beta titanium investment-casting alloy.
Reference datasheet — ZTC4 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 Annealed condition
ZTC4 tempers and conditions
ZTC4 is supplied in 5 conditions, soft to hard. Annealed 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 |
|---|---|---|---|---|---|---|
As fabricated | Cheapest condition for non-critical corrosion or general engineering castings where GB/T 6614 minimum properties suffice. | 820 | 890 | 6 | 34 HRC | — |
AnnealedDefault 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 | — |
Supply forms, finishes and certifications
Ways ZTC4 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
BA | Beta annealed | Surface finish |
What is ZTC4?
ZTC4 (UNS R56406) is the GB national-standard designation for cast Ti-6Al-4V, the cast counterpart of wrought TC4 and the workhorse alpha-beta titanium investment-casting alloy. It delivers 840 MPa yield, 910 MPa tensile, 8 % elongation and 325 HB / 35 HRC with service to about 350 °C, and is supplied as-cast, annealed, HIP, HIP + annealed, STA or beta-annealed. Machinability is the lowest in this family (score 18), the alpha case must be chemically milled off, and elongation is below ELI cast Ti-6Al-4V (C-23), which is the alternative for fracture-critical work. ZTC4 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). ZTC4 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).
What is ZTC4 used for?
- aerospace structural castings
- pump/valve bodies
- impellers
- biomedical implant castings
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 properties
Typical room-temperature values for ZTC4-Annealed; bars are the position among titanium grades.
Physical3
ZTC4 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 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 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 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 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'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. 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. ZTC4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZTC4
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.
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 |
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.
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 ZTC4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R56406
- Also called
- Ti-6Al-4V Casting
How much does ZTC4 cost?
ZTC4 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.
ZTC4 — frequently asked
What is ZTC4 used for?
ZTC4 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?
ZTC4 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 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 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?
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 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?
ZTC4 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.
How much does ZTC4 cost?
ZTC4 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 (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; 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.