Aluminum AL9
AL9 is an Al-Si-Mg (AlSi7Mg) casting alloy specified in GOST 1583 and comparable to ASTM 355.0, strengthened by Mg2Si precipitation in the T5, T6 and T61 tempers.
Reference datasheet — AL9 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
AL9 tempers and conditions
AL9 is supplied in 7 conditions, soft to hard. T6 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working, cold worked and naturally aged | Pick when maximum dimensional stability and machining freedom matter more than strength. | 85 | 150 | 6 | 50 HB | 44 % IACS |
As fabricated | Cheapest condition for low-stress, dimensionally stable housings and covers. | 90 | 165 | 4 | 55 HB | 43 % IACS |
Solution heat treated and naturally aged | Best ductility/impact combination for castings that must tolerate shock or later straightening. | 115 | 210 | 8 | 60 HB | 36 % IACS |
Cooled from hot working and artificially aged | Low-distortion strength boost without quenching — good for thin, complex permanent-mould parts. | 140 | 195 | 3 | 68 HB | 41 % IACS |
Solution heat treated and overaged (stabilized) | Use for parts running warm or needing long-term dimensional stability with better toughness than T6. | 170 | 215 | 5 | 70 HB | 41 % IACS |
T6Default Solution heat treated and artificially aged | Standard high-strength condition for structural and pressure-tight castings; most commonly ordered. | 185 | 240 | 4 | 80 HB | 39 % IACS |
T6 variant, underaged | Chosen where maximum hardness/wear resistance is needed and ductility can be sacrificed. | 215 | 265 | 3 | 90 HB | 39 % IACS |
What is AL9?
AL9 is an Al-Si-Mg (AlSi7Mg) casting alloy specified in GOST 1583 and comparable to ASTM 355.0, strengthened by Mg2Si precipitation in the T5, T6 and T61 tempers. It is chosen for pressure-tight sand, permanent-mould, low-pressure and investment castings, with default-condition values of 185 MPa yield, 240 MPa tensile, 4% elongation, 80 HB and 151 W/m·K. Limits are a maximum service temperature of about 150 °C and modest ductility; where copper-bearing chip control matters more than corrosion resistance (58 score), 319.0/LM27 is the nearest alternative. AL9 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F). AL9 has a yield strength of 185 MPa (26.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 53% of aluminum grades. Elongation at break is 4% and the elastic modulus is 72.4 GPa (10.5 Msi).
What is AL9 used for?
- Pump bodies
- Cylinder heads
- Pressure-tight valve bodies
- Gearbox and transmission housings
- Impellers
- Hydraulic housings
- Aircraft and instrument fittings
Limitations
- Limited formability — 10/100, worse than 80% of aluminum grades
AL9 properties
Typical room-temperature values for AL9-T6; bars are the position among aluminum grades.
Physical3
AL9 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F).
Mechanical13
AL9 has a yield strength of 185 MPa (26.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 53% of aluminum grades. Elongation at break is 4% and the elastic modulus is 72.4 GPa (10.5 Msi).
Thermal6
AL9 is rated for continuous service to 150°C (302 °F). It conducts heat at 151 W/m·K (87.2 BTU/hr·ft·°F), better than 63% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AL9 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of AL9 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 60%.
Manufacturability8
AL9's machinability is good (60/100, worse than 51% of aluminum grades); weldability very good (80/100); 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. AL9 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AL9
Is AL9 easy to machine?
Machines easily with sharp PCD or polished carbide tools and high speeds; the eutectic Si is abrasive, so PCD is preferred for volume, and chips are gummy in F/T2 — age to T6 for better surface finish.
Can AL9 be welded?
Very good GTAW/GMAW weldability with 4043 or 4047 filler; re-solution and re-age locally repaired areas to restore T6 strength and avoid HAZ softening.
Can AL9 be formed, bent or molded?
Foundry alloy with excellent fluidity and low hot-tearing risk — suitable for sand, permanent-mould, low-pressure and investment casting; modify with Sr/Na and grain-refine with Ti-B, and use chills for feeding-critical sections.
AL9 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 |
|---|---|---|
| SiGOST 1583 AK7ch (АЛ9) | 6 – 8 | 7 |
| Mgprincipal strengthener (Mg2Si) | 0.2 – 0.4 | 0.3 |
| Mn | ≤ 0.5 | 0.2 |
| Fe≤1.0 % for pressure die castings; lower Fe improves ductility | ≤ 0.6 | 0.3 |
| Cu | ≤ 0.2 | 0.05 |
| Zn | ≤ 0.3 | 0.05 |
| Tigrain refinement | ≤ 0.1 | 0.08 |
| Beoptional melt-protection addition | ≤ 0.1 | |
| Al | balance |
What surface finishes work on AL9?
Takes chromate/phosphate conversion coatings and paint well; hardcoat anodize is protective but grey and mottled from the silicon, and shot blasting plus impregnation is common for pressure-tight parts.
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 AL9 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 355.0
How much does AL9 cost?
AL9 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.
AL9 — frequently asked
What is AL9 used for?
AL9 is typically used for pump bodies, cylinder heads, pressure-tight valve bodies, gearbox and transmission housings, impellers and hydraulic housings. In short: pressure-tight AlSi7Mg casting; heat treatable to T6; weldable cast aluminum.
What is the yield strength of AL9?
AL9 has a typical yield strength of 185 MPa (26.8 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 53% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is AL9 easy to machine?
Reasonably — machinability is rated good (60/100, worse than 51% of aluminum grades). Machines easily with sharp PCD or polished carbide tools and high speeds; the eutectic Si is abrasive, so PCD is preferred for volume, and chips are gummy in F/T2 — age to T6 for better surface finish.
Can AL9 be welded?
Yes — weldability is rated very good (80/100). Very good GTAW/GMAW weldability with 4043 or 4047 filler; re-solution and re-age locally repaired areas to restore T6 strength and avoid HAZ softening.
What surface finishes work on AL9?
Takes chromate/phosphate conversion coatings and paint well; hardcoat anodize is protective but grey and mottled from the silicon, and shot blasting plus impregnation is common for pressure-tight parts.
Can AL9 be formed, bent or molded?
Foundry alloy with excellent fluidity and low hot-tearing risk — suitable for sand, permanent-mould, low-pressure and investment casting; modify with Sr/Na and grain-refine with Ti-B, and use chills for feeding-critical sections.
What is the maximum service temperature of AL9?
AL9 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 AL9-T6 and AL9-T2?
T6 is the default condition — standard high-strength condition for structural and pressure-tight castings; most commonly ordered. T2: pick when maximum dimensional stability and machining freedom matter more than strength. Yield strength is 185 MPa in T6 versus 85 MPa in T2.
How much does AL9 cost?
AL9 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
- GOST 1583 — Aluminium casting alloys (AK7ch / АЛ9) — Gosstandart (1993)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- GB/T 1173 — Casting aluminium alloys (ZL101A) — SAC (2013)
- ASM Handbook Vol. 2 — Properties of Aluminum and Aluminum Alloys (356.0/A356.0) — ASM International (1990)
- Aluminum Association Teal Sheets — Registered casting alloy compositions — The Aluminum Association (2015)
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.