Aluminum AlSi7Mg · temper
Aluminum AlSi7Mg T6-CAST
Properties of the T6-CAST condition, compared with the other AlSi7Mg tempers.
Sand/permanent-mould EN AC-42000 solution treated near 540 °C, water quenched and peak-aged for maximum strength and hardness with limited ductility.
What is AlSi7Mg T6-CAST?
AlSi7Mg T6-CAST is AlSi7Mg in the T6-CAST temper — sand/permanent-mould EN AC-42000 solution treated near 540 °C, water quenched and peak-aged for maximum strength and hardness with limited ductility. AlSi7Mg T6-CAST has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 58% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72 GPa (10.4 Msi). AlSi7Mg T6-CAST has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 557°C (1,035 °F). As Printed is the default condition FabDigit quotes; T6-CAST is available on request or by drawing note.
AlSi7Mg T6-CAST properties
Typical room-temperature values for AlSi7Mg T6-CAST — 39 properties are specific to this condition; the rest are grade-level values shared by every AlSi7Mg temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
AlSi7Mg T6-CAST has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 557°C (1,035 °F).
Mechanical14
AlSi7Mg T6-CAST has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 58% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
AlSi7Mg T6-CAST 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
AlSi7Mg T6-CAST conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 67% of aluminum grades.
Sustainability4
Producing a kilogram of AlSi7Mg T6-CAST takes about 195 MJ of energy and emits 12 kg of CO₂ — less than 86% of aluminum grades. Typical recycled content is 35%.
Manufacturability8
AlSi7Mg T6-CAST's machinability is very good (70/100, better than 72% of aluminum grades); weldability good (65/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other AlSi7Mg tempers and conditions
AlSi7Mg is also supplied in 7 other conditions. The full side-by-side table is on the AlSi7Mg overview.
- As PrintedDefaultHighest as-built strength from the ultrafine cellular Si network; use for non-critical or dimensionally simple parts where residual stress and anisotropy are acceptable.240 MPa yield · 105 HB
- T6Highest strength condition and the usual delivery state for structural brackets and housings; accept some ductility loss and quench-distortion risk.300 MPa yield · 115 HB
- HIP+T6Best overall combination for qualified flight hardware: porosity-free structure with near-T6 strength and clearly improved elongation and fatigue life.290 MPa yield · 112 HB
- T6-CASTSand/permanent-mould EN AC-42000 solution treated near 540 °C, water quenched and peak-aged for maximum strength and hardness with limited ductility.220 MPa yield · 85 HB
- Stress RelievedStandard first step for thin-wall or distortion-sensitive geometry: removes build residual stress and raises ductility at some cost in strength.200 MPa yield · 90 HB
- T64Under-aged casting temper of EN AC-42000: slightly lower strength than T6 but noticeably higher elongation, toughness and fatigue crack resistance for structural castings.195 MPa yield · 80 HB
- HIPChoose for fatigue- and fracture-critical aerospace parts: HIP closes internal gas/lack-of-fusion porosity and homogenises the structure, giving high ductility at annealed-level strength.185 MPa yield · 85 HB
- FEN AC-42000 (AlSi7Mg / A356) in the as-cast, non-heat-treated F condition — modest strength, good ductility and excellent castability.90 MPa yield · 55 HB
Working with AlSi7Mg T6-CAST
Is AlSi7Mg easy to machine?
Machines like a Si-bearing casting alloy: use polished-flute carbide or PCD tools, high speed, low feed and flood coolant/air-blast to stop chip welding; expect abrasive tool wear from primary Si.
Can AlSi7Mg be welded?
Readily laser- or TIG-welded and AM-repairable, best with 4043/4047 filler; avoid autogenous welding of thick sections in T6 as the HAZ softens and requires re-solution/age.
Can AlSi7Mg be formed, bent or molded?
Not a formable alloy — geometry comes from the build; design self-supporting angles >45°, keep walls ≥0.4 mm and stress-relieve on the plate before cutting off supports to limit distortion.
What surface finishes work on AlSi7Mg?
Blast/tumble or machine off the as-built roughness (Ra 8–15 µm), then chemical conversion (chromate-free Ti/Zr) or hard/Type II anodise; anodised colour is dark grey, and shot-peening plus HIP is the usual route to fatigue-rated surfaces.
AlSi7Mg 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 |
|---|---|---|
| Si | 6.5 – 7.5 | 7 |
| Mg0.55–0.6 typical for AM powder | 0.45 – 0.7 | 0.6 |
| Ti | 0.04 – 0.2 | 0.12 |
| FeF357/AM powder often ≤0.12 | ≤ 0.2 | 0.1 |
| Cu | ≤ 0.05 | 0.01 |
| Mn | ≤ 0.1 | 0.01 |
| Zn | ≤ 0.07 | 0.01 |
| Be0.04–0.07 in A357; F357 is beryllium-free and is the grade normally used for AM | ≤ 0.07 | 0 |
| Opowder oxygen pickup limit | ≤ 0.05 | 0.02 |
| Others (each/total)0.05 each / 0.15 total | ≤ 0.15 | — |
| Al | balance | — |
AlSi7Mg T6-CAST — frequently asked
What is AlSi7Mg T6-CAST used for?
AlSi7Mg T6-CAST is typically used for aerospace housings and fittings, cast-replacement structural brackets, valve bodies and manifolds, satellite and instrument frames, pump and gearbox housings and motorsport suspension components. In short: castable LPBF aluminum alloy.
What is the yield strength of AlSi7Mg T6-CAST?
AlSi7Mg T6-CAST has a typical yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 58% of aluminum grades. Strength varies by condition: see the 8 listed tempers.
Is AlSi7Mg T6-CAST easy to machine?
Yes — machinability is rated very good (70/100, better than 72% of aluminum grades). Machines like a Si-bearing casting alloy: use polished-flute carbide or PCD tools, high speed, low feed and flood coolant/air-blast to stop chip welding; expect abrasive tool wear from primary Si.
Can AlSi7Mg T6-CAST be welded?
Yes — weldability is rated good (65/100). Readily laser- or TIG-welded and AM-repairable, best with 4043/4047 filler; avoid autogenous welding of thick sections in T6 as the HAZ softens and requires re-solution/age.
What surface finishes work on AlSi7Mg T6-CAST?
Blast/tumble or machine off the as-built roughness (Ra 8–15 µm), then chemical conversion (chromate-free Ti/Zr) or hard/Type II anodise; anodised colour is dark grey, and shot-peening plus HIP is the usual route to fatigue-rated surfaces.
Can AlSi7Mg T6-CAST be formed, bent or molded?
Not a formable alloy — geometry comes from the build; design self-supporting angles >45°, keep walls ≥0.4 mm and stress-relieve on the plate before cutting off supports to limit distortion.
What is the maximum service temperature of AlSi7Mg T6-CAST?
AlSi7Mg T6-CAST 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 AlSi7Mg As Printed and AlSi7Mg-F?
As Printed is the default condition — highest as-built strength from the ultrafine cellular Si network; use for non-critical or dimensionally simple parts where residual stress and anisotropy are acceptable. F: eN AC-42000 (AlSi7Mg / A356) in the as-cast, non-heat-treated F condition — modest strength, good ductility and excellent castability. Yield strength is 240 MPa in As Printed versus 90 MPa in F.
Can FabDigit make parts in AlSi7Mg T6-CAST?
Yes — AlSi7Mg T6-CAST is available for 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM F3318 — Additive Manufacturing of Aluminium Alloy AlSi7Mg0.6 (F357) via Laser PBF — ASTM International (2018)
- AMS 4289 / AMS 2771 — A357 casting alloy and heat treatment of aluminium castings — SAE International (2019)
- EN 1706 (EN AC-42200 AlSi7Mg0.6) — CEN (2020)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- LPBF AlSi7Mg0.6 / F357 powder and material datasheets — EOS / SLM Solutions / Constellium-Aheadd class producers (2023)
- Al-Si-Mg additive manufacturing property compilations — MMPDS-supporting AM literature and NIST AM Bench reports (2022)
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.