Magnesium Alloy ZC63A-T6
Temper · default condition
ASTM ZC63A · UNS M16331
T6 = solution heat treated and artificially aged
The standard supply condition — best combination of yield strength, pressure tightness and adequate ductility for structural castings.
Values for the T6 condition
Other ZC63A tempers and conditions
ZC63A is listed in 4 conditions; see the grade overview at ZC63A.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated and naturally aged | Solution-treated only: maximum ductility and impact toughness, lower yield strength; sometimes an intermediate stage before ageing. | 100 | 200 | 8 | 50 HB | 21 % IACS |
As fabricated | Untreated castings for low-stress or dimensionally critical parts where the T6 growth/distortion is unacceptable. | 110 | 175 | 3 | 52 HB | 24 % IACS |
T6DefaultThis page Solution heat treated and artificially aged | The standard supply condition — best combination of yield strength, pressure tightness and adequate ductility for structural castings. | 145 | 210 | 5 | 60 HB | 24 % IACS |
T6 | Permanent-mold castings with finer structure: choose when higher strength and tighter section soundness are required. | 155 | 235 | 6 | 65 HB | 24 % IACS |
What is ZC63A-T6?
ZC63A-T6 is ZC63A in the T6 temper — the standard supply condition — best combination of yield strength, pressure tightness and adequate ductility for structural castings. ZC63A-T6 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 51% of magnesium alloy grades. Elongation at break is 5% and the elastic modulus is 45 GPa (6.53 Msi). ZC63A-T6 has a density of 1.87 g/cm³ (0.0676 lb/in³), heavier than 99% of magnesium alloy grades. It melts at 465°C (869 °F).
Advantages
- Conducts heat well — 122 W/m·K (70.5 BTU/hr·ft·°F), better than 88% of magnesium alloy grades
Limitations
- Difficult to weld — 40/100, worse than 75% of magnesium alloy grades
ZC63A-T6 properties
Typical room-temperature values for ZC63A-T6; 21 are specific to this condition. Other listed values are ZC63A reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
ZC63A-T6 has a density of 1.87 g/cm³ (0.0676 lb/in³), heavier than 99% of magnesium alloy grades. It melts at 465°C (869 °F).
Mechanical15
ZC63A-T6 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 51% of magnesium alloy grades. Elongation at break is 5% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
ZC63A-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 122 W/m·K (70.5 BTU/hr·ft·°F), better than 88% of magnesium alloy grades. Thermal expansion is 27 µm/m·K (15 µin/in·°F).
Electrical3
ZC63A-T6 conducts electricity at 24 % IACS, better than 58% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), worse than 88% of magnesium alloy grades.
Sustainability4
Producing a kilogram of ZC63A-T6 takes about 330 MJ of energy and emits 33 kg of CO₂ — less than 56% of magnesium alloy grades. Typical recycled content is 25%.
Manufacturability8
ZC63A-T6's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability fair (40/100); 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 ZC63A-T6
Is ZC63A easy to machine?
Machines extremely fast with sharp, high-rake carbide tools and generous chip clearance; use dry or mineral-oil coolant (never water-based) and control fine chips/dust for fire risk.
Can ZC63A be welded?
GTAW/GMAW with matching or AZ92A filler is possible after solution treatment, but the high Zn content makes it hot-crack sensitive — preheat, low restraint and post-weld re-solution/age are recommended.
Can ZC63A be formed, bent or molded?
Sand and permanent-mold casting alloy with good feeding and pressure tightness; use SF6-free (SO2/HFC-134a) melt protection, grain-refine by superheat or Zr-free Mn practice, and design for T6 solution soak with controlled quench.
What surface finishes work on ZC63A?
Requires chromate/chrome-free conversion coating or Dow 17 / HAE / PEO anodic film plus epoxy primer and topcoat; isolate all steel and CFRP fasteners to avoid galvanic attack.
ZC63A 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 |
|---|---|---|
| Znprimary strengthener | 5.5 – 6.5 | 6 |
| Curefines eutectic, improves pressure tightness; harms corrosion resistance | 2.4 – 3 | 2.7 |
| Mniron control / corrosion mitigation | 0.25 – 0.75 | 0.5 |
| Si | ≤ 0.2 | — |
| Ni | ≤ 0.01 | — |
| Others (each) | ≤ 0.01 | — |
| Others (total) | ≤ 0.3 | — |
| Mg | balance | — |
ZC63A-T6 — frequently asked
What is ZC63A-T6 used for?
ZC63A-T6 is typically used for automotive sand castings, pressure-tight industrial housings, gearbox and pump casings, permanent-mould structural brackets, hydraulic and pneumatic valve bodies and equipment covers requiring leak-tight walls. In short: rare-earth-free high-strength Mg casting; better pressure tightness than AZ91; very high machinability.
What is the yield strength of ZC63A-T6?
ZC63A-T6 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 51% of magnesium alloy grades. Strength varies by condition: see the 4 listed tempers.
Is ZC63A-T6 easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Machines extremely fast with sharp, high-rake carbide tools and generous chip clearance; use dry or mineral-oil coolant (never water-based) and control fine chips/dust for fire risk.
Can ZC63A-T6 be welded?
With care — weldability is rated fair (40/100). GTAW/GMAW with matching or AZ92A filler is possible after solution treatment, but the high Zn content makes it hot-crack sensitive — preheat, low restraint and post-weld re-solution/age are recommended.
What surface finishes work on ZC63A-T6?
Requires chromate/chrome-free conversion coating or Dow 17 / HAE / PEO anodic film plus epoxy primer and topcoat; isolate all steel and CFRP fasteners to avoid galvanic attack.
Can ZC63A-T6 be formed, bent or molded?
Sand and permanent-mold casting alloy with good feeding and pressure tightness; use SF6-free (SO2/HFC-134a) melt protection, grain-refine by superheat or Zr-free Mn practice, and design for T6 solution soak with controlled quench.
What is the maximum service temperature of ZC63A-T6?
ZC63A-T6 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZC63A-T6 and ZC63A-T4?
T6 is the default condition — the standard supply condition — best combination of yield strength, pressure tightness and adequate ductility for structural castings. T4: solution-treated only: maximum ductility and impact toughness, lower yield strength; sometimes an intermediate stage before ageing. Yield strength is 145 MPa in T6 versus 100 MPa in T4.
Sources
- ASTM B80 — Standard Specification for Magnesium-Alloy Sand Castings — ASTM International (2021)
- ASTM B199 — Magnesium-Alloy Permanent Mold Castings — ASTM International (2019)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Magnesium) — ASM International (2005)
- SAE J465 / UNS M16331 alloy designation — SAE International / ASTM-SAE UNS (2018)
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.