Magnesium and magnesium alloys are standardized primarily under
ASTM (commercial & industrial use) and AMS
(Aerospace Material Specifications – SAE). Both systems define chemistry,
mechanical properties, processing condition, and inspection requirements, but
they serve different industries and rigor levels.
ASTM Standards for Magnesium
| ASTM Standard | Scope |
|---|
| ASTM B92 | Magnesium ingots & castings |
| ASTM B93 / B93M | Magnesium alloy extrusions |
| ASTM B94 | Magnesium alloy sheets & plates |
| ASTM B90 / B90M | Magnesium alloy die castings |
| ASTM B107 / B107M | Extruded bars, rods & tubes |
| ASTM B843 | Magnesium alloy forgings |
| ASTM G97 | Magnesium sacrificial anodes |
ASTM Magnesium Alloy Designation System
| Symbol | Meaning |
|---|
| A | Aluminum (primary alloying element) |
| Z | Zinc (secondary element) |
| 31 | Approx. 3% Al, 1% Zn |
| B | Revision/version of composition |
Common ASTM Magnesium Grades
| ASTM Grade | Nominal Composition | Typical Product |
|---|
| AZ31B | 3% Al – 1% Zn | Sheet, plate, extrusion |
| AZ61A | 6% Al – 1% Zn | Extrusions |
| AZ80A | 8% Al | Plates, forgings |
| AZ91D | 9% Al – 1% Zn | Die castings |
| AM50A | 5% Al – Mn | Automotive castings |
| AM60B | 6% Al – Mn | Structural die cast |
| ZK60A | Zn – Zr | High-strength wrought |
| WE43A | Y – Rare Earths | Aerospace |
| M1C / M2 | Mn-containing | Sacrificial anodes |
AMS (Aerospace) Magnesium Specifications
AMS specifications are significantly stricter than ASTM and are mandatory for
aerospace, defense, and high-reliability applications. They require tight
chemistry control, defined process routes, inspection, and full traceability.
| AMS Standard | Scope |
|---|
| AMS 4375 | Magnesium alloy sheet & plate |
| AMS 4376 | Magnesium alloy sheet |
| AMS 4343 | Magnesium alloy extrusions |
| AMS 4350 | Magnesium alloy forgings |
| AMS 4439 | Magnesium alloy sand castings |
| AMS 4417 | Magnesium alloy die castings |
| AMS 4383 | High-purity magnesium |
Common AMS Magnesium Grades
| AMS Grade | Equivalent Alloy | Product Form |
|---|
| AMS 4375 | AZ31B | Sheet & plate |
| AMS 4376 | AZ31 | Sheet |
| AMS 4343 | AZ31 / AZ61 | Extrusions |
| AMS 4439 | AZ91 | Castings |
| AMS 4350 | AZ80 / ZK60 | Forgings |
| AMS 4383 | High-purity Mg | Ingots / billets |
| AMS 4429 | WE43 | Aerospace castings |
| AMS 4444 | WE54 | High-temp aerospace |
ASTM vs AMS – When to Use Which
| Aspect | ASTM | AMS |
|---|
| Industry | General / Automotive | Aerospace / Defense |
| Chemistry Control | Standard | Very tight |
| Process Control | Limited | Strict |
| Certification | Mill test report | Full traceability |
| Cost | Lower | Higher |
| Acceptance | Commercial | Aviation authorities |
Why Understanding ASTM & AMS Grades Matters
✔ Ensures correct material selection
✔ Prevents over-specifying (costly) or under-specifying (failure)
✔ Required for aerospace qualification and audits
✔ Critical for buyer–supplier technical alignment
In simple terms:
ASTM = Industry & volume use
AMS = Aerospace & zero-failure tolerance
