Aluminum 2A70
GB 2A70
2A70 (LD7) is a heat-resistant Al-Cu-Mg-Fe-Ni forging alloy in the GB 2000-series family, supplied in O, F, T4, T6 and T652 and functionally similar to 2618.
Reference datasheet — 2A70 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 T6 condition
2A70 tempers and conditions
2A70 is supplied in 5 conditions, soft to hard. T6 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 | Softest condition for deep forming, straightening or intermediate machining before heat treatment. | 120 | 230 | 18 | 65 HB | 48 % IACS |
As fabricated | Raw hot-worked forging or extrusion before solution treatment; used only as a semi-finished supply state. | 160 | 280 | 15 | 80 HB | 42 % IACS |
Solution heat treated and naturally aged | Intermediate state for parts that must be formed or straightened after quenching and then artificially aged. | 205 | 350 | 18 | 95 HB | 33 % IACS |
T6, stress relieved by compression | Choose for large forgings that must be heavily machined — residual stress is removed so parts stay dimensionally stable. | 345 | 420 | 9 | 118 HB | 38 % IACS |
T6Default Solution heat treated and artificially aged | Standard supply condition for pistons, impellers and hot-running forgings — peak strength plus stable elevated-temperature properties. | 350 | 430 | 10 | 120 HB | 38 % IACS |
What is 2A70?
2A70 (LD7) is a heat-resistant Al-Cu-Mg-Fe-Ni forging alloy in the GB 2000-series family, supplied in O, F, T4, T6 and T652 and functionally similar to 2618. It is used for pistons and other engine hardware because it keeps strength to about 200 °C, with default T6 values of 430 MPa tensile, 350 MPa yield, 10% elongation, 120 HB and 145 W/m·K. The trade-offs are very low formability (25), corrosion resistance of 32, abrasive intermetallic particles that shorten tool life, and no practical fusion weldability. 2618 is the nearest alternative. 2A70 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 505°C (941 °F). 2A70 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 83% of aluminum grades. Elongation at break is 10% and the elastic modulus is 73 GPa (10.6 Msi).
What is 2A70 used for?
- Forged engine pistons
- High-temperature forged structural parts
- Engine accessory brackets and links
- Extruded sections for elevated-temperature service
- Hot-section machined fittings
- Compressor and engine housings
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- High strength — 350 MPa (50.8 ksi), better than 83% of aluminum grades
- Easy to machine — 72/100, better than 80% of aluminum grades
Limitations
- Needs corrosion protection — 32/100, worse than 94% of aluminum grades
- Difficult to weld — 22/100, worse than 83% of aluminum grades
2A70 properties
Typical room-temperature values for 2A70-T6; bars are the position among aluminum grades.
Physical3
2A70 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 505°C (941 °F).
Mechanical15
2A70 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 83% of aluminum grades. Elongation at break is 10% and the elastic modulus is 73 GPa (10.6 Msi).
Thermal6
2A70 is rated for continuous service to 200°C (392 °F). It conducts heat at 145 W/m·K (83.8 BTU/hr·ft·°F), better than 53% of aluminum grades. Thermal expansion is 22.3 µm/m·K (12.4 µin/in·°F).
Electrical3
2A70 conducts electricity at 38 % IACS, better than 61% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), worse than 94% of aluminum grades.
Sustainability4
Producing a kilogram of 2A70 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 10%.
Manufacturability8
2A70's machinability is very good (72/100, better than 80% of aluminum grades); weldability poor (22/100); formability poor (25/100).
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. 2A70 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 2A70
Is 2A70 easy to machine?
Machines well in T6 with sharp carbide tools and flood coolant, but the hard Al9FeNi/Al7Cu2Fe particles are abrasive — expect faster tool wear than 6061 and use PCD for high-volume piston turning.
Can 2A70 be welded?
Fusion welding is not recommended (hot-cracking, loss of aged strength); join by bolting, riveting, shrink fit or friction/inertia welding with post-weld re-ageing.
Can 2A70 be formed, bent or molded?
Designed for hot die forging and extrusion at roughly 380–460 °C; cold forming in T6 is very limited, form in O or T4 and age afterwards.
2A70 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 |
|---|---|---|
| Cu | 1.9 – 2.5 | 2.2 |
| Mg | 1.4 – 1.8 | 1.6 |
| Fedeliberate addition, forms Al9FeNi | 0.9 – 1.5 | 1.2 |
| Niheat-resistance phase former | 0.9 – 1.5 | 1.2 |
| Tigrain refiner | 0.02 – 0.1 | 0.05 |
| Si | ≤ 0.35 | |
| Mn | ≤ 0.2 | |
| Zn | ≤ 0.3 | |
| Others (each)total ≤ 0.15 | ≤ 0.05 | |
| Al | balance |
What surface finishes work on 2A70?
Use hard or chromic anodizing, chemical conversion coating or Ni/Sn plating for pistons; decorative sulfuric anodizing gives dark uneven color due to Cu-Ni phases.
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 2A70 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GB (China)
- LD7
How much does 2A70 cost?
2A70 is a premium-cost aluminum ($$$), cheaper than about 51% 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.
2A70 — frequently asked
What is 2A70 used for?
2A70 is typically used for forged engine pistons, high-temperature forged structural parts, engine accessory brackets and links, extruded sections for elevated-temperature service, hot-section machined fittings and compressor and engine housings. In short: service to 200 °C; 2618-class piston alloy; abrasive Fe-Ni phases.
What is the yield strength of 2A70?
2A70 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 83% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 2A70 easy to machine?
Yes — machinability is rated very good (72/100, better than 80% of aluminum grades). Machines well in T6 with sharp carbide tools and flood coolant, but the hard Al9FeNi/Al7Cu2Fe particles are abrasive — expect faster tool wear than 6061 and use PCD for high-volume piston turning.
Can 2A70 be welded?
Not readily — weldability is rated poor (22/100). Fusion welding is not recommended (hot-cracking, loss of aged strength); join by bolting, riveting, shrink fit or friction/inertia welding with post-weld re-ageing.
What surface finishes work on 2A70?
Use hard or chromic anodizing, chemical conversion coating or Ni/Sn plating for pistons; decorative sulfuric anodizing gives dark uneven color due to Cu-Ni phases.
Can 2A70 be formed, bent or molded?
Designed for hot die forging and extrusion at roughly 380–460 °C; cold forming in T6 is very limited, form in O or T4 and age afterwards.
What is the maximum service temperature of 2A70?
2A70 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 2A70-T6 and 2A70-O?
T6 is the default condition — standard supply condition for pistons, impellers and hot-running forgings — peak strength plus stable elevated-temperature properties. O: softest condition for deep forming, straightening or intermediate machining before heat treatment. Yield strength is 350 MPa in T6 versus 120 MPa in O.
How much does 2A70 cost?
2A70 is a premium-cost aluminum ($$$), cheaper than about 51% 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 (2618 data) — ASM International (1990)
- Aluminum Association Teal Sheets — alloy/temper designations — The Aluminum Association (2018)
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.