Magnesium Alloy AZ31B · temper
Magnesium Alloy AZ31B-F
Properties of the F condition, compared with the other AZ31B tempers.
Standard condition for extrusions and forgings per ASTM B107/B91 — no post-extrusion treatment; properties are directional (longitudinal quoted).
What is AZ31B-F?
AZ31B-F is AZ31B in the F temper — standard condition for extrusions and forgings per ASTM B107/B91 — no post-extrusion treatment; properties are directional (longitudinal quoted). AZ31B-F has a yield strength of 200 MPa (29 ksi) and a tensile strength of 260 MPa (37.7 ksi) — stronger than 88% of magnesium alloy grades. Elongation at break is 15% and the elastic modulus is 45 GPa (6.53 Msi). AZ31B-F has a density of 1.77 g/cm³ (0.0639 lb/in³), lighter than 86% of magnesium alloy grades. It melts at 566°C (1,051 °F). O is the default condition FabDigit quotes; F is available on request or by drawing note.
Advantages
- High strength — 200 MPa (29 ksi), better than 88% of magnesium alloy grades
- Ductile — tolerates forming and impact — 15%, better than 87% of magnesium alloy grades
- Forms and bends easily — 35/100, better than 87% of magnesium alloy grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 78% of magnesium alloy grades
AZ31B-F properties
Typical room-temperature values for AZ31B-F — 42 properties are specific to this condition; the rest are grade-level values shared by every AZ31B temper. Each bar shows where the value sits among the magnesium alloy grades in FabDigit's library — further right is higher.
Physical3
AZ31B-F has a density of 1.77 g/cm³ (0.0639 lb/in³), lighter than 86% of magnesium alloy grades. It melts at 566°C (1,051 °F).
Mechanical15
AZ31B-F has a yield strength of 200 MPa (29 ksi) and a tensile strength of 260 MPa (37.7 ksi) — stronger than 88% of magnesium alloy grades. Elongation at break is 15% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
AZ31B-F is rated for continuous service to 120°C (248 °F). It conducts heat at 96 W/m·K (55.5 BTU/hr·ft·°F), better than 50% of magnesium alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
AZ31B-F conducts electricity at 18.5 % IACS, worse than 51% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 64% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AZ31B-F takes about 330 MJ of energy and emits 32 kg of CO₂ — less than 56% of magnesium alloy grades. Typical recycled content is 25%.
Manufacturability8
AZ31B-F's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability very good (70/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other AZ31B tempers and conditions
AZ31B is also supplied in 4 other conditions. The full side-by-side table is on the AZ31B overview.
- ODefaultPick for maximum formability and deep drawing (usually warm-formed at 230–290 °C); lowest strength temper.150 MPa yield · 49 HB
- H26Choose for thin sheet needing the highest as-rolled strength and stiffness with little forming.235 MPa yield · 77 HB
- H24The standard stocked sheet/plate temper: best balance of strength, flatness and usable ductility for machined plate and structural panels.220 MPa yield · 73 HB
- FStandard condition for extrusions and forgings per ASTM B107/B91 — no post-extrusion treatment; properties are directional (longitudinal quoted).200 MPa yield · 49 HB
- H22Lightly cold-rolled then partially annealed AZ31B sheet — strength between O and H24 with useful residual formability.190 MPa yield · 65 HB
Working with AZ31B-F
Is AZ31B easy to machine?
Best machinability of any structural metal — high speeds, sharp positive-rake tools, dry or with mineral oil (never water-based coolant); collect and never let fine chips accumulate, keep Class D extinguishing media on hand.
Can AZ31B be welded?
Readily GTAW/GMAW welded with AZ61A or AZ92A filler and argon shielding; low heat input, no preheat needed on thin sheet, stress-relieve 150 °C/1 h after welding H tempers to avoid SCC.
Can AZ31B be formed, bent or molded?
Cold formability is limited by basal-slip texture — bend/draw warm at 230–300 °C where elongation exceeds 50 %; use generous bend radii (5–7 t cold) and heated tooling.
What surface finishes work on AZ31B?
Do not use conventional sulfuric anodize; specify chromate-free conversion coating or Dow 17 / HAE / PEO anodic film plus epoxy primer and topcoat, and isolate from steel/aluminium fasteners to prevent galvanic attack.
AZ31B 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 |
|---|---|---|
| Alsolid-solution strengthener | 2.5 – 3.5 | 3 |
| Zn | 0.6 – 1.4 | 1 |
| Mnmin 0.20 % for corrosion control (Fe tie-up) | 0.2 – 0.5 | 0.3 |
| Si | ≤ 0.1 | — |
| Cu | ≤ 0.05 | — |
| Ca | ≤ 0.04 | — |
| Fehigh-purity limit | ≤ 0.01 | — |
| Nihigh-purity limit | ≤ 0.01 | — |
| Others (each)others total 0.30 max | ≤ 0.05 | — |
| Mgbalance, ~96 % | balance | — |
AZ31B-F — frequently asked
What is AZ31B-F used for?
AZ31B-F is typically used for laptop and tablet housings, mobile phone shells, camera and optics bodies, drone and gimbal frame parts, lightweight electronics enclosures and covers and extruded structural profiles and rails. In short: standard wrought magnesium.
What is the yield strength of AZ31B-F?
AZ31B-F has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 260 MPa (37.7 ksi) — stronger than 88% of magnesium alloy grades. Strength varies by condition: see the 5 listed tempers.
Is AZ31B-F easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Best machinability of any structural metal — high speeds, sharp positive-rake tools, dry or with mineral oil (never water-based coolant); collect and never let fine chips accumulate, keep Class D extinguishing media on hand.
Can AZ31B-F be welded?
Yes — weldability is rated very good (70/100). Readily GTAW/GMAW welded with AZ61A or AZ92A filler and argon shielding; low heat input, no preheat needed on thin sheet, stress-relieve 150 °C/1 h after welding H tempers to avoid SCC.
What surface finishes work on AZ31B-F?
Do not use conventional sulfuric anodize; specify chromate-free conversion coating or Dow 17 / HAE / PEO anodic film plus epoxy primer and topcoat, and isolate from steel/aluminium fasteners to prevent galvanic attack.
Can AZ31B-F be formed, bent or molded?
Cold formability is limited by basal-slip texture — bend/draw warm at 230–300 °C where elongation exceeds 50 %; use generous bend radii (5–7 t cold) and heated tooling.
What is the maximum service temperature of AZ31B-F?
AZ31B-F is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AZ31B-O and AZ31B-H26?
O is the default condition — pick for maximum formability and deep drawing (usually warm-formed at 230–290 °C); lowest strength temper. H26: choose for thin sheet needing the highest as-rolled strength and stiffness with little forming. Yield strength is 150 MPa in O versus 235 MPa in H26.
Can FabDigit make parts in AZ31B-F?
Yes — AZ31B-F is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B90/B90M — Magnesium-Alloy Sheet and Plate — ASTM International (2021)
- ASTM B107/B107M — Magnesium-Alloy Extruded Bars, Rods, Profiles, Tubes and Wire — ASTM International (2021)
- ASTM B91 — Magnesium-Alloy Forgings — ASTM International (2017)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
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.