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True Precision Machining

Material datasheet · Mg-Al-Zn alloy

Magnesium Alloy AZ31B

UNS M11311 · H24 (strain-hardened, partial anneal) or O (annealed)

Lightest commonly-machined structural metal. Excellent damping. Fire-safe machining required.

UTS
41 ksi
285 MPa
Yield strength
29 ksi
200 MPa
Elongation
15%
in 2″
Hardness
73 HB
Typical
Density
0.064
lb/in³ · 1.78 g/cc
Modulus E
6.5
Mpsi · 45 GPa
CTE
14.4
µin/in·°F
Service T (max)
300°F
Continuous

Chemical composition

Nominal % by weight.

Element % by wt
Mg Bal.
Al 2.5–3.5
Zn 0.6–1.4
Mn ≥0.20

Applicable specifications

AMS / ASTM / MIL.

  • AMS 4375 (AZ31B-O, sheet/plate)
  • AMS 4377 (AZ31B-H24, sheet/plate)
  • ASTM B107

Machining guidance

CNC parameters and tooling.

Roughing SFM
1500–3000
Finishing SFM
2500–4000
Machinability rating
100 / 100
B1112 = 100
Coolant
Mineral oil or dry; never water-based (fire/H₂ explosion risk)
Tooling

Sharp carbide or HSS

Notes

Fire-safe machining required: sharp tools, large chip evacuation, no water-based coolant. Class D fire extinguisher on hand.

Stock & cost

Forms and Q1 2026 pricing.

Available forms
SheetPlateBarExtrusion
Stock cost
$15.00–$25.00/lb
Mid-quantity bar/plate, Q1 2026 USD
Common finishes
  • Chromate conversion (MIL-DTL-5541 equivalent for Mg)
  • E-coat
  • Anodize (Tagnite, Keronite)

Typical applications

Where Magnesium AZ31 is the right pick.

  • Aerospace lightweight brackets
  • Electronics housings
  • Optical mounts
  • Racing components
  • Camera bodies

Alternative materials

Substitute or upgrade options.

  • AZ91 (cast)
  • WE43 (high T, aerospace)
  • Aluminum 6061 (heavier, safer)

True Precision Machining · Buellton, CA

Machine your part in Magnesium AZ31.

5-axis CNC · ISO 9001 · AS9100 · ITAR · CMMC-compliant · DFARS-compliant supply chain. AS9102 FAI on aerospace.

Phone: 805-964-4545
Email: info@trueprecisionmachining.com
Web: trueprecisionmachining.com
Datasheet generated 2026 · Mechanical values are typical room-T averages from MMPDS / ASM. Verify against MTRs for design-critical applications.

Technically reviewed by the True Precision Machining engineering team · Last reviewed June 2026

Standards referenced: AMS 4375 (AZ31B-O, sheet/plate), AMS 4377 (AZ31B-H24, sheet/plate), ASTM B107