Aluminum AlSi7Mg · heat-treated state
Aluminum AlSi7Mg Stress Relieved
Properties of the Stress Relieved condition, compared with the other AlSi7Mg tempers.
Standard first step for thin-wall or distortion-sensitive geometry: removes build residual stress and raises ductility at some cost in strength.
What is AlSi7Mg Stress Relieved?
AlSi7Mg Stress Relieved is AlSi7Mg heat treated to Stress Relieved — standard first step for thin-wall or distortion-sensitive geometry: removes build residual stress and raises ductility at some cost in strength. AlSi7Mg Stress Relieved has a yield strength of 200 MPa (29 ksi) and a tensile strength of 300 MPa (43.5 ksi) — stronger than 52% of aluminum grades. Elongation at break is 12% and the elastic modulus is 71 GPa (10.3 Msi). AlSi7Mg Stress Relieved 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; Stress Relieved is available on request or by drawing note.
AlSi7Mg Stress Relieved properties
Typical room-temperature values for AlSi7Mg Stress Relieved — 11 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 Stress Relieved 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 Stress Relieved has a yield strength of 200 MPa (29 ksi) and a tensile strength of 300 MPa (43.5 ksi) — stronger than 52% of aluminum grades. Elongation at break is 12% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
AlSi7Mg Stress Relieved is rated for continuous service to 150°C (302 °F). It conducts heat at 150 W/m·K (86.7 BTU/hr·ft·°F), better than 58% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AlSi7Mg Stress Relieved conducts electricity at 36 % IACS, better than 55% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of AlSi7Mg Stress Relieved takes about 215 MJ of energy and emits 13 kg of CO₂ — more than 92% of aluminum grades. Typical recycled content is 10%.
Manufacturability8
AlSi7Mg Stress Relieved's machinability is good (60/100, better than 50% of aluminum grades); weldability very good (70/100); formability poor (20/100).
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 Stress Relieved
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 Stress Relieved — frequently asked
What is AlSi7Mg Stress Relieved used for?
AlSi7Mg Stress Relieved 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 Stress Relieved?
AlSi7Mg Stress Relieved has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 300 MPa (43.5 ksi) — stronger than 52% of aluminum grades. Strength varies by condition: see the 8 listed tempers.
Is AlSi7Mg Stress Relieved easy to machine?
Reasonably — machinability is rated good (60/100, better than 50% 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 Stress Relieved be welded?
Yes — weldability is rated very good (70/100). 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 Stress Relieved?
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 Stress Relieved 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 Stress Relieved?
AlSi7Mg Stress Relieved 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 Stress Relieved?
Yes — AlSi7Mg Stress Relieved 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.