Aluminum AL25
AL25 is an Al-Cu-Ni-Mg piston casting alloy to GOST 1583, comparable to ASTM 242.0, developed to retain strength at elevated temperature in diesel engines.
Reference datasheet — AL25 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 condition
AL25 tempers and conditions
AL25 is supplied in 6 conditions, soft to hard. T1 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working, cold worked and naturally aged | Choose the stress-relief annealed state when dimensional stability and low residual stress matter more than strength; yield falls to 120 MPa while conductivity rises to 145 W/m·K. | 120 | 160 | 1.2 | 70 HB | 32 % IACS |
As fabricated | Use the untreated as-cast chill or permanent-mould state for lightly loaded parts, or as the starting point before heat treatment; 150 MPa yield with only 0.8% elongation. | 150 | 180 | 0.8 | 85 HB | 29 % IACS |
Solution heat treated and overaged (stabilized) | Select solution treated and stabilised (over-aged) for long-term service up to 300 °C with no further growth; yield drops to 170 MPa but thermal and dimensional stability are best. | 170 | 195 | 0.9 | 95 HB | 30 % IACS |
T1Default Cooled from hot working and naturally aged | Pick for volume piston production: artificial ageing without a quench keeps distortion and cost low while giving 180 MPa yield, 95 HB and good thermal stability to 250 °C. | 180 | 200 | 0.6 | 95 HB | 27 % IACS |
Cooled from hot working and artificially aged | Use solution treated and partially (short) aged when you need more strength than the aged-only state (190 MPa yield, 100 HB) but must retain some ductility in thermally loaded castings. | 190 | 215 | 0.7 | 100 HB | 25 % IACS |
Solution heat treated and artificially aged | Choose solution treated and fully artificially aged for the highest room- and mid-temperature strength — 205 MPa yield, 110 HB — in highly rated diesel pistons; elongation drops to 0.5%. | 205 | 230 | 0.5 | 110 HB | 24 % IACS |
What is AL25?
AL25 is an Al-Cu-Ni-Mg piston casting alloy to GOST 1583, comparable to ASTM 242.0, developed to retain strength at elevated temperature in diesel engines. It is specified for gravity permanent-mould and low-pressure castings that run hot, with default values of 180 MPa yield, 200 MPa tensile, 95 HB, 130 W/m·K and a maximum service temperature of 250 °C. The trade-offs are very low ductility (0.6% elongation), poor fusion weldability from the Cu and Mg content, and moderate machinability (48); use 355.0-type alloys where ductility and weld repair matter more than hot strength. AL25 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 510°C (950 °F). AL25 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 54% of aluminum grades. Elongation at break is 0.6% and the elastic modulus is 80 GPa (11.6 Msi).
What is AL25 used for?
- Diesel engine pistons
- Turbocharger components
- Air-cooled cylinder heads
- Engine crankcases
- Piston ring carriers
- Elevated-temperature bearing housings
Advantages
- High service temperature — 250°C (482 °F), better than 97% of aluminum grades
- Stiff — 80 GPa (11.6 Msi), better than 95% of aluminum grades
Limitations
- Limited ductility — 0.6%, worse than 98% of aluminum grades
- Limited formability — 5/100, worse than 94% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Low fracture toughness — 16 MPa·√m (14.6 ksi·√in), worse than 89% of aluminum grades
- Low electrical conductivity — 27 % IACS, worse than 86% of aluminum grades
AL25 properties
Typical room-temperature values for AL25-T1; bars are the position among aluminum grades.
Physical3
AL25 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 510°C (950 °F).
Mechanical14
AL25 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 54% of aluminum grades. Elongation at break is 0.6% and the elastic modulus is 80 GPa (11.6 Msi).
Thermal6
AL25 is rated for continuous service to 250°C (482 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), worse than 65% of aluminum grades. Thermal expansion is 19 µm/m·K (10.6 µin/in·°F).
Electrical3
AL25 conducts electricity at 27 % IACS, worse than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 85% of aluminum grades.
Sustainability4
Producing a kilogram of AL25 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 60%.
Manufacturability8
AL25's machinability is fair (48/100, worse than 68% of aluminum grades); weldability poor (25/100); formability not recommended (5/100).
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. AL25 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AL25
Is AL25 easy to machine?
The abrasive high-silicon eutectic structure calls for PCD or diamond-coated tooling with high speed, light feed and ample coolant; dimensional accuracy achieved this way is good.
Can AL25 be welded?
Fusion welding is generally not recommended, as the Cu and Mg content causes hot cracking and property loss; for repair only, TIG with 4047 or 4145 filler after a 200 °C preheat, then re-age.
Can AL25 be formed, bent or molded?
Cast mainly by gravity permanent mould, and also by low-pressure casting; the near-eutectic composition gives good fluidity and low hot-tearing tendency, but requires sound feeding and Sr/P modification to control silicon morphology. Not workable cold.
AL25 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 |
|---|---|---|
| Sieutectic Si, lowers CTE, raises wear resistance and castability | 11 – 13 | 12 |
| Cu | 1.5 – 3 | 2 |
| Mg | 0.8 – 1.3 | 1 |
| Niforms heat-resistant intermetallics | 0.8 – 1.3 | 1 |
| Mn | 0.3 – 0.6 | 0.45 |
| Tigrain refiner | 0.05 – 0.2 | 0.1 |
| Feimpurity limit | ≤ 0.8 | |
| Znimpurity limit | ≤ 0.5 | |
| Crimpurity limit | ≤ 0.2 | |
| Pbimpurity limit | ≤ 0.1 | |
| Snimpurity limit | ≤ 0.02 | |
| Alper GOST 1583 AL25 (AK12M2MgN); ASTM 242.0 matched by use only | balance |
What surface finishes work on AL25?
Hard anodizing is standard on piston crowns and ring grooves, with phosphating or tin plating as alternatives; decorative anodizing is poor because the high silicon gives a dull grey finish.
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 AL25 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 242.0
How much does AL25 cost?
AL25 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.
AL25 — frequently asked
What is AL25 used for?
AL25 is typically used for diesel engine pistons, turbocharger components, air-cooled cylinder heads, engine crankcases, piston ring carriers and elevated-temperature bearing housings. In short: highest hot strength, 250 °C; classic piston alloy; very low ductility.
What is the yield strength of AL25?
AL25 has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 54% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is AL25 easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 68% of aluminum grades). The abrasive high-silicon eutectic structure calls for PCD or diamond-coated tooling with high speed, light feed and ample coolant; dimensional accuracy achieved this way is good.
Can AL25 be welded?
Not readily — weldability is rated poor (25/100). Fusion welding is generally not recommended, as the Cu and Mg content causes hot cracking and property loss; for repair only, TIG with 4047 or 4145 filler after a 200 °C preheat, then re-age.
What surface finishes work on AL25?
Hard anodizing is standard on piston crowns and ring grooves, with phosphating or tin plating as alternatives; decorative anodizing is poor because the high silicon gives a dull grey finish.
Can AL25 be formed, bent or molded?
Cast mainly by gravity permanent mould, and also by low-pressure casting; the near-eutectic composition gives good fluidity and low hot-tearing tendency, but requires sound feeding and Sr/P modification to control silicon morphology. Not workable cold.
What is the maximum service temperature of AL25?
AL25 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AL25-T1 and AL25-T2?
T1 is the default condition — pick for volume piston production: artificial ageing without a quench keeps distortion and cost low while giving 180 MPa yield, 95 HB and good thermal stability to 250 °C. T2: choose the stress-relief annealed state when dimensional stability and low residual stress matter more than strength; yield falls to 120 MPa while conductivity rises to 145 W/m·K. Yield strength is 180 MPa in T1 versus 120 MPa in T2.
How much does AL25 cost?
AL25 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
- ГОСТ 1583 — Сплавы алюминиевые литейные (АЛ25 / АК12М2МгН) — Госстандарт (1993)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (cast Al-Si-Cu-Ni piston alloys, 336.0/242.0) — ASM International (1990)
- GB/T 1173 — (ZL109) — SAC (2013)
- ASM Handbook Vol.13B — Corrosion: Materials (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.