Aluminum AL9-T61
Temper
T61 = t6 variant, underaged
Chosen where maximum hardness/wear resistance is needed and ductility can be sacrificed.
Values for the T61 condition
Other AL9 tempers and conditions
AL9 is listed in 7 conditions; see the grade overview at AL9.
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 |
T61This page 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-T61?
AL9-T61 is AL9 in the T61 temper — chosen where maximum hardness/wear resistance is needed and ductility can be sacrificed. AL9-T61 has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 58% of aluminum grades. Elongation at break is 3% and the elastic modulus is 72.4 GPa (10.5 Msi). AL9-T61 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). T6 is the default condition FabDigit quotes; T61 is available on request or by drawing note.
Limitations
- Limited formability — 8/100, worse than 88% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
AL9-T61 properties
Typical room-temperature values for AL9-T61; 20 are specific to this condition. Other listed values are AL9 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AL9-T61 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-T61 has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 58% of aluminum grades. Elongation at break is 3% and the elastic modulus is 72.4 GPa (10.5 Msi).
Thermal6
AL9-T61 is rated for continuous service to 150°C (302 °F). It conducts heat at 152 W/m·K (87.8 BTU/hr·ft·°F), better than 66% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AL9-T61 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of AL9-T61 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-T61's machinability is good (62/100, better than 55% of aluminum grades); weldability very good (75/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AL9-T61
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.
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.
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 | — |
AL9-T61 — frequently asked
What is AL9-T61 used for?
AL9-T61 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-T61?
AL9-T61 has a typical yield strength of 215 MPa (31.2 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 58% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is AL9-T61 easy to machine?
Reasonably — machinability is rated good (62/100, better than 55% 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-T61 be welded?
Yes — weldability is rated very good (75/100). 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-T61?
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-T61 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-T61?
AL9-T61 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.