Aluminum ZL402
GB ZL402 · ASTM 771.0
ZL402 (ZAlZn6Mg, equivalent to 771.0) is an Al-Zn-Mg casting alloy that ages naturally, reaching useful strength in the T1 condition without solution treatment and quenching.
Reference datasheet — ZL402 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 T1-J condition
ZL402 tempers and conditions
ZL402 is supplied in 3 conditions, soft to hard. T1-J is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Freshly cast, un-aged condition; strength keeps rising for weeks at room temperature, so machine only after stabilization. | 110 | 190 | 7 | 55 HB | 31 % IACS |
T1 | Sand-cast parts stabilized by aging; choose for large or one-off housings where metal-mould tooling is not justified. | 140 | 225 | 5 | 62 HB | 34 % IACS |
T1-JDefault T1 | Standard commercial condition: metal-mould casting aged to stable strength — best combination of strength, dimensional stability and surface finish. | 150 | 240 | 5 | 72 HB | 35 % IACS |
What is ZL402?
ZL402 (ZAlZn6Mg, equivalent to 771.0) is an Al-Zn-Mg casting alloy that ages naturally, reaching useful strength in the T1 condition without solution treatment and quenching. It is cast in sand and permanent moulds for general engineering parts; default values are 240 MPa tensile, 150 MPa yield, 5 % elongation, 72 HB, 140 W/m·K and 35 % IACS, with machinability rated 72. Dimensions drift while natural ageing completes, the Al-Zn-Mg system is stress-corrosion sensitive at weld toes, and service is limited to 150 °C. ZL114A is the alternative when heat-treated strength is required. ZL402 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 605°C (1,121 °F). ZL402 has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 65% of aluminum grades. Elongation at break is 5% and the elastic modulus is 70 GPa (10.2 Msi).
What is ZL402 used for?
- General engineering castings
- Low-stress structural parts
- Housings and covers
- Brackets and supports
- Machine frames and bases
- Fixture and jig bodies
Advantages
- Polishes to a fine finish — 70/100, better than 87% of aluminum grades
- Easy to machine — 72/100, better than 80% of aluminum grades
Limitations
- Limited formability — 10/100, worse than 80% of aluminum grades
ZL402 properties
Typical room-temperature values for ZL402-T1-J; bars are the position among aluminum grades.
Physical3
ZL402 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 605°C (1,121 °F).
Mechanical13
ZL402 has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 65% of aluminum grades. Elongation at break is 5% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZL402 is rated for continuous service to 150°C (302 °F). It conducts heat at 140 W/m·K (80.9 BTU/hr·ft·°F), worse than 52% of aluminum grades. Thermal expansion is 24 µm/m·K (13.3 µin/in·°F).
Electrical3
ZL402 conducts electricity at 35 % IACS, better than 52% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 55% of aluminum grades.
Sustainability4
Producing a kilogram of ZL402 takes about 190 MJ of energy and emits 13.5 kg of CO₂ — less than 89% of aluminum grades. Typical recycled content is 40%.
Manufacturability8
ZL402's machinability is very good (72/100, better than 80% of aluminum grades); weldability good (55/100); 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 aluminum family
Yield strength against density for every aluminum grade FabDigit runs. ZL402 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZL402
Is ZL402 easy to machine?
Machines cleanly with sharp PCD/carbide tooling and high speeds; wait for aging to stabilize (1–4 weeks at RT or a short 120–140 °C stabilizing soak) before finish cuts to avoid dimensional drift.
Can ZL402 be welded?
TIG/MIG weldable with 5356 or 5183 filler; the Al-Zn-Mg HAZ naturally re-ages back to useful strength, but chilled restraint and slow cooling are needed to avoid hot cracking and SCC-prone weld toes.
Can ZL402 be formed, bent or molded?
Sand and permanent-mould casting only — the alloy has moderate fluidity and a wide freezing range, so use generous risers, chills and controlled pouring (700–730 °C) to prevent hot tearing and shrinkage porosity; no solution quench is required.
ZL402 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 |
|---|---|---|
| Znprincipal strengthener with Mg (MgZn2) | 5 – 6.5 | 5.8 |
| Mg | 0.5 – 0.65 | 0.57 |
| Crgrain-boundary control, improves SCC resistance | 0.4 – 0.6 | 0.5 |
| Tigrain refiner | 0.15 – 0.25 | 0.2 |
| Siimpurity limit | ≤ 0.3 | |
| Feimpurity limit | ≤ 0.5 | |
| Cuimpurity limit | ≤ 0.25 | |
| Mnimpurity limit | ≤ 0.1 | |
| Al | balance |
What surface finishes work on ZL402?
Takes chromate/trivalent conversion coatings, clear or hard anodizing and paint well; polishes to a bright machined finish, but Zn-rich segregation can mottle dyed anodic films.
Surface treatments FabDigit runs on aluminum 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).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum ZL402 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- 771.0
- GB (China)
- ZAlZn6Mg
How much does ZL402 cost?
ZL402 is a standard-cost aluminum ($$), cheaper than about 71% 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.
ZL402 — frequently asked
What is ZL402 used for?
ZL402 is typically used for general engineering castings, low-stress structural parts, housings and covers, brackets and supports, machine frames and bases and fixture and jig bodies. In short: self-ageing casting alloy; no solution treatment needed; freely machining ZL grade.
What is the yield strength of ZL402?
ZL402 has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 65% of aluminum grades. Strength varies by condition: see the 3 listed tempers.
Is ZL402 easy to machine?
Yes — machinability is rated very good (72/100, better than 80% of aluminum grades). Machines cleanly with sharp PCD/carbide tooling and high speeds; wait for aging to stabilize (1–4 weeks at RT or a short 120–140 °C stabilizing soak) before finish cuts to avoid dimensional drift.
Can ZL402 be welded?
Yes — weldability is rated good (55/100). TIG/MIG weldable with 5356 or 5183 filler; the Al-Zn-Mg HAZ naturally re-ages back to useful strength, but chilled restraint and slow cooling are needed to avoid hot cracking and SCC-prone weld toes.
What surface finishes work on ZL402?
Takes chromate/trivalent conversion coatings, clear or hard anodizing and paint well; polishes to a bright machined finish, but Zn-rich segregation can mottle dyed anodic films.
Can ZL402 be formed, bent or molded?
Sand and permanent-mould casting only — the alloy has moderate fluidity and a wide freezing range, so use generous risers, chills and controlled pouring (700–730 °C) to prevent hot tearing and shrinkage porosity; no solution quench is required.
What is the maximum service temperature of ZL402?
ZL402 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 ZL402 T1-J and ZL402-F?
T1-J is the default condition — standard commercial condition: metal-mould casting aged to stable strength — best combination of strength, dimensional stability and surface finish. F: freshly cast, un-aged condition; strength keeps rising for weeks at room temperature, so machine only after stabilization. Yield strength is 150 MPa in T1-J versus 110 MPa in F.
How much does ZL402 cost?
ZL402 is a standard-cost aluminum ($$), cheaper than about 71% 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
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (Al casting alloys, 771.0) — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion of Aluminum Alloys — 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.