Magnesium Alloy AZ31C
ASTM AZ31C · UNS M11312
AZ31C is a wrought Mg-3Al-1Zn sheet, plate and extrusion alloy (UNS M11312) supplied in F, O, H24 and H26 with wider impurity limits, and lower cost, than aerospace-grade AZ31B.
Reference datasheet — AZ31C 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
AZ31C tempers and conditions
AZ31C is supplied in 4 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum ductility when the sheet must be deep-drawn or warm-formed; lowest yield strength. | 150 | 255 | 21 | 56 HB | 18.5 % IACS |
FDefault As fabricated | Standard stocked condition for AZ31C extrusions and machined blanks; best balance of strength, straightness and price. | 200 | 260 | 15 | 49 HB | — |
Strain hardened and partially annealed, half hard | The usual sheet/plate condition: highest yield strength with useful residual ductility for mild forming and machining. | 220 | 290 | 15 | 73 HB | 18.5 % IACS |
Strain hardened and partially annealed, three-quarter hard | Occasional heavier-plate/temper-rolled condition when slightly higher strength and flatness are wanted; lower ductility than H24. | 230 | 295 | 12 | 75 HB | 18.5 % IACS |
What is AZ31C?
AZ31C is a wrought Mg-3Al-1Zn sheet, plate and extrusion alloy (UNS M11312) supplied in F, O, H24 and H26 with wider impurity limits, and lower cost, than aerospace-grade AZ31B. Engineers select it for light, stiff panels and profiles where the highest machinability score of any structural metal (100) and good arc weldability (75) matter more than tight chemistry. Typical properties are about 200 MPa yield, 260 MPa tensile, 15% elongation and 49 HB. Cold formability is poor (30), service is capped near 120 °C, and the looser Fe/Ni/Cu limits reduce corrosion resistance, so AZ31B is used when corrosion life or certification governs. AZ31C 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). AZ31C 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).
What is AZ31C used for?
- General-purpose extruded profiles
- Commercial magnesium sheet stock
- Lightweight equipment covers and panels
- Instrument and electronics chassis
- Handheld tool frames
- Sporting goods and camera bodies
- Machined jigs and lightweight fixtures
Advantages
- Readily welded — 75/100, better than 91% of magnesium alloy grades
- 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 — 30/100, better than 82% of magnesium alloy grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 78% of magnesium alloy grades
AZ31C properties
Typical room-temperature values for AZ31C-F; bars are the position among magnesium alloy grades.
Physical3
AZ31C 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).
Mechanical14
AZ31C 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
AZ31C 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
AZ31C conducts electricity at 18.5 % IACS, worse than 51% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), worse than 96% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AZ31C takes about 355 MJ of energy and emits 32 kg of CO₂ — more than 85% of magnesium alloy grades. Typical recycled content is 30%.
Manufacturability8
AZ31C's machinability is excellent (100/100, better than 100% of magnesium alloy grades); weldability very good (75/100); formability poor (30/100).
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. AZ31C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AZ31C
Is AZ31C easy to machine?
Machines faster and with lower power than any other structural metal — use sharp, high-rake tools, generous chip clearance, dry or mineral-oil cutting (never water-based coolant) and keep fine chips wet-free and away from ignition sources.
Can AZ31C be welded?
Readily GTAW/GMAW welded with AZ61A or AZ92A filler using argon or Ar-He; preheat only lightly, avoid Zn-rich fillers, and stress relieve H-temper sheet weldments (~150 °C/1 h) to prevent SCC.
Can AZ31C be formed, bent or molded?
Cold formability is poor because of the basal texture; bend and draw warm (200–300 °C) with heated dies, and use generous bend radii (≥5t cold) or the O temper.
AZ31C 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 |
|---|---|---|
| Al | 2.4 – 3.6 | 3 |
| Zn | 0.5 – 1.5 | 1 |
| Mnminimum only in most registrations | ≥ 0.15 | 0.3 |
| Si | ≤ 0.1 | |
| Culooser than AZ31B (0.05 max) — key difference | ≤ 0.1 | |
| Nilooser than AZ31B (0.005 max) | ≤ 0.03 | |
| Ca | ≤ 0.04 | |
| Others (each)total of unspecified elements | ≤ 0.3 | |
| Mgbalance, ~95–96 % | balance |
What surface finishes work on AZ31C?
Do not sulfuric-anodize; degrease, acid-pickle then apply a chromate-free conversion coat or Dow 17/HAE/PEO anodic coating followed by epoxy primer and topcoat, and isolate all steel or brass fasteners to avoid galvanic pitting.
Equivalent designations
Standards and trade names that resolve to Magnesium Alloy AZ31C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- M11312
- Also called
- AZ31C-F
How much does AZ31C cost?
AZ31C is a premium-cost magnesium alloy ($$$), cheaper than about 51% 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.
AZ31C — frequently asked
What is AZ31C used for?
AZ31C is typically used for general-purpose extruded profiles, commercial magnesium sheet stock, lightweight equipment covers and panels, instrument and electronics chassis, handheld tool frames and sporting goods and camera bodies. In short: lower-cost AZ31 variant; highest machinability of structural metals; weldable wrought magnesium.
What is the yield strength of AZ31C?
AZ31C 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 4 listed tempers.
Is AZ31C easy to machine?
Yes — machinability is rated excellent (100/100, better than 100% of magnesium alloy grades). Machines faster and with lower power than any other structural metal — use sharp, high-rake tools, generous chip clearance, dry or mineral-oil cutting (never water-based coolant) and keep fine chips wet-free and away from ignition sources.
Can AZ31C be welded?
Yes — weldability is rated very good (75/100). Readily GTAW/GMAW welded with AZ61A or AZ92A filler using argon or Ar-He; preheat only lightly, avoid Zn-rich fillers, and stress relieve H-temper sheet weldments (~150 °C/1 h) to prevent SCC.
What surface finishes work on AZ31C?
Do not sulfuric-anodize; degrease, acid-pickle then apply a chromate-free conversion coat or Dow 17/HAE/PEO anodic coating followed by epoxy primer and topcoat, and isolate all steel or brass fasteners to avoid galvanic pitting.
Can AZ31C be formed, bent or molded?
Cold formability is poor because of the basal texture; bend and draw warm (200–300 °C) with heated dies, and use generous bend radii (≥5t cold) or the O temper.
What is the maximum service temperature of AZ31C?
AZ31C 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 AZ31C-F and AZ31C-O?
F is the default condition — standard stocked condition for AZ31C extrusions and machined blanks; best balance of strength, straightness and price. O: pick for maximum ductility when the sheet must be deep-drawn or warm-formed; lowest yield strength. Yield strength is 200 MPa in F versus 150 MPa in O.
How much does AZ31C cost?
AZ31C is a premium-cost magnesium alloy ($$$), cheaper than about 51% 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
- ASTM B107/B107M — Magnesium-Alloy Extruded Bars, Rods, Profiles, Tubes, and Wire — ASTM International (2013)
- ASTM B90/B90M — Magnesium-Alloy Sheet and Plate — ASTM International (2021)
- ASTM B275 — Codification of Certain Nonferrous Metals and Alloys (UNS M11312) — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Magnesium and Magnesium Alloys) — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Corrosion of Magnesium) — ASM International (2005)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
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.