Magnesium Alloy AM20-F (As fabricated)
Temper · default condition
ASTM AM20 · EN MC21210, MgAl2Mn
Standard supply condition: thin-wall HPDC parts used as-cast for maximum ductility and crash energy absorption.
Values for the F condition
Other AM20 tempers and conditions
AM20 is listed in 2 conditions; see the grade overview at AM20.
- F-SC
- F
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-cast, sand / permanent-mould | Occasional low-volume prototype or thick-section castings; coarser grain gives lower strength than HPDC. | 70 | 150 | 9 | 40 HB | 23 % IACS |
FDefaultThis page As fabricated | Standard supply condition: thin-wall HPDC parts used as-cast for maximum ductility and crash energy absorption. | 90 | 195 | 12 | 45 HB | 22 % IACS |
What is AM20-F?
AM20-F is AM20 in the F temper — standard supply condition: thin-wall HPDC parts used as-cast for maximum ductility and crash energy absorption. AM20-F has a yield strength of 90 MPa (13.1 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 96% of magnesium alloy grades. Elongation at break is 12% and the elastic modulus is 45 GPa (6.53 Msi). AM20-F has a density of 1.76 g/cm³ (0.0636 lb/in³), lighter than 94% of magnesium alloy grades. It melts at 620°C (1,148 °F).
Advantages
- Low embodied carbon — 25 kg CO₂/kg, better than 100% of magnesium alloy grades
Limitations
- Limited service temperature — 110°C (230 °F), worse than 99% of magnesium alloy grades
- Low strength — 90 MPa (13.1 ksi), worse than 96% of magnesium alloy grades
AM20-F properties
Typical room-temperature values for AM20-F; 20 are specific to this condition. Other listed values are AM20 reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
AM20-F has a density of 1.76 g/cm³ (0.0636 lb/in³), lighter than 94% of magnesium alloy grades. It melts at 620°C (1,148 °F).
Mechanical14
AM20-F has a yield strength of 90 MPa (13.1 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 96% of magnesium alloy grades. Elongation at break is 12% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
AM20-F is rated for continuous service to 110°C (230 °F). It conducts heat at 100 W/m·K (57.8 BTU/hr·ft·°F), better than 57% of magnesium alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
AM20-F conducts electricity at 22 % IACS, better than 55% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 64% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AM20-F takes about 290 MJ of energy and emits 25 kg of CO₂ — less than 99% of magnesium alloy grades. Typical recycled content is 30%.
Manufacturability8
AM20-F's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability fair (50/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AM20-F
Is AM20 easy to machine?
Cuts extremely fast with sharp positive-rake tools and low forces; use flood coolant or dry with chip control and never water-mist — fine chips/dust are a fire hazard requiring Class D extinguishers.
Can AM20 be welded?
GTAW/GMAW with AZ61A/AZ92A filler works on wrought or low-porosity zones, but HPDC gas porosity blisters, so repair welding of die castings is generally avoided.
Can AM20 be formed, bent or molded?
Hot-chamber or cold-chamber HPDC at ~660–690 °C melt with SF6-free cover gas; lower Al than AZ91 means poorer fluidity and more hot-tear risk, so favour uniform thin walls and generous fillets.
What surface finishes work on AM20?
Requires chemical conversion coating (chrome-free) or Mg anodize plus e-coat/powder; ensure sealed fasteners and insulating washers to stop galvanic attack at steel joints.
AM20 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 |
|---|---|---|
| Allow Al for high ductility | 1.6 – 2.5 | 2 |
| MnFe control / corrosion | 0.2 – 0.6 | 0.4 |
| Zn | ≤ 0.2 | 0.05 |
| Si | ≤ 0.1 | 0.03 |
| Cuhigh-purity limit | ≤ 0.01 | 0 |
| Nihigh-purity limit | ≤ 0 | 5×10⁻⁴ |
| Fehigh-purity limit | ≤ 0 | 0 |
| Others (each) | ≤ 0.01 | — |
| Mg | balance | — |
AM20-F — frequently asked
What is AM20-F used for?
AM20-F is typically used for automotive seat frames, steering wheel armatures, interior brackets and die-cast housings. In short: most ductile Mg-Al die casting; impact-toughness grade below AM60; low strength, high machinability.
What is the yield strength of AM20-F?
AM20-F has a typical yield strength of 90 MPa (13.1 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 96% of magnesium alloy grades. Strength varies by condition: see the 2 listed tempers.
Is AM20-F easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Cuts extremely fast with sharp positive-rake tools and low forces; use flood coolant or dry with chip control and never water-mist — fine chips/dust are a fire hazard requiring Class D extinguishers.
Can AM20-F be welded?
With care — weldability is rated fair (50/100). GTAW/GMAW with AZ61A/AZ92A filler works on wrought or low-porosity zones, but HPDC gas porosity blisters, so repair welding of die castings is generally avoided.
What surface finishes work on AM20-F?
Requires chemical conversion coating (chrome-free) or Mg anodize plus e-coat/powder; ensure sealed fasteners and insulating washers to stop galvanic attack at steel joints.
Can AM20-F be formed, bent or molded?
Hot-chamber or cold-chamber HPDC at ~660–690 °C melt with SF6-free cover gas; lower Al than AZ91 means poorer fluidity and more hot-tear risk, so favour uniform thin walls and generous fillets.
What is the maximum service temperature of AM20-F?
AM20-F is rated for continuous use to about 110°C (230 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AM20-F and AM20 F-SC?
F is the default condition — standard supply condition: thin-wall HPDC parts used as-cast for maximum ductility and crash energy absorption. F-SC: occasional low-volume prototype or thick-section castings; coarser grain gives lower strength than HPDC. Yield strength is 90 MPa in F versus 70 MPa in F-SC.
Sources
- ISO 16220 Magnesium and magnesium alloys — Magnesium alloy ingots and castings — ISO (2017)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Magnesium die-casting alloy data (AM-series) — Mg alloy ingot producers (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.