Magnesium Alloy AM20
ASTM AM20 · EN MC21210, MgAl2Mn
AM20 (AM20A, UNS MC21210, MgAl2Mn) is a low-aluminium Mg-Al-Mn die-casting alloy supplied as F, F-SC and ingot.
Reference datasheet — AM20 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 F condition
AM20 tempers and conditions
AM20 is supplied in 2 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
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 |
FDefault 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 |
Supply forms, finishes and certifications
Ways AM20 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Ingot | Remelt stock for die casting | Supply form |
What is AM20?
AM20 (AM20A, UNS MC21210, MgAl2Mn) is a low-aluminium Mg-Al-Mn die-casting alloy supplied as F, F-SC and ingot. It is specified where energy absorption and impact toughness matter more than peak strength, giving 90 MPa yield, 195 MPa tensile, 12 % elongation and 45 HB with a machinability rating of 95. Strength is well below AZ91, service temperature is limited to 110 °C, castings need coating for corrosion protection, and the low Al content reduces fluidity. AM60 is the usual step up when more strength is required at similar ductility. AM20 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). AM20 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).
What is AM20 used for?
- automotive seat frames
- steering wheel armatures
- interior brackets
- die-cast housings
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 properties
Typical room-temperature values for AM20-F; bars are the position among magnesium alloy grades.
Physical3
AM20 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 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 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 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 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'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. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the magnesium alloy family
Yield strength against density for every magnesium alloy grade FabDigit runs. AM20 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AM20
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.
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 |
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.
Equivalent designations
Standards and trade names that resolve to Magnesium Alloy AM20 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- AM20A
- EN / DIN / Werkstoff-Nr.
- MC21210MgAl2Mn
How much does AM20 cost?
AM20 is a standard-cost magnesium alloy ($$), 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.
AM20 — frequently asked
What is AM20 used for?
AM20 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?
AM20 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 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 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?
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 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?
AM20 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.
How much does AM20 cost?
AM20 is a standard-cost magnesium alloy ($$), 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
- 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; 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.