Magnesium Alloy MB8
MB8 is a sheet-grade wrought magnesium alloy in the AZ31C class, supplied in M, R, Y2, Y, extruded and forged conditions for thin-gauge formed and welded components.
Reference datasheet — MB8 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 M condition
MB8 tempers and conditions
MB8 is supplied in 5 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Most commonly stocked sheet condition — maximum ductility for warm forming, deep drawing and welded assemblies. | 140 | 240 | 18 | 50 HB | 25 % IACS |
Forged / die-forged condition | Hot-forged blanks for aerospace housings needing isotropic properties and elevated-temperature stability. | 150 | 250 | 12 | 52 HB | 25 % IACS |
Hot-rolled sheet | As-hot-rolled thicker plate/sheet; slightly higher strength than annealed with useful ductility, common for gauges above ~4 mm. | 155 | 250 | 14 | 53 HB | 25 % IACS |
Half-hard rolled sheet | Compromise between strength and bendability for mildly formed panels and covers. | 175 | 255 | 10 | 56 HB | 25 % IACS |
Hard rolled sheet | Highest strength / flattest thin-gauge sheet; choose for flat stiff panels that will not be formed. | 200 | 270 | 6 | 62 HB | 25 % IACS |
Supply forms, finishes and certifications
Ways MB8 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EXT | As-extruded bar, tube and profile | Supply form |
What is MB8?
MB8 is a sheet-grade wrought magnesium alloy in the AZ31C class, supplied in M, R, Y2, Y, extruded and forged conditions for thin-gauge formed and welded components. Engineers select it for enclosures and stampings that need warm forming (formability score 45) and dependable arc welding, with a service ceiling near 200 °C. Strength is modest at 140 MPa yield, 240 MPa tensile, 18 % elongation and 50 HB, and bare surfaces require a conversion coating and paint. MB2 (AZ31B) is the nearest equivalent sheet product. MB8 has a density of 1.78 g/cm³ (0.0643 lb/in³), lighter than 78% of magnesium alloy grades. It melts at 645°C (1,193 °F). MB8 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 61% of magnesium alloy grades. Elongation at break is 18% and the elastic modulus is 45 GPa (6.53 Msi).
What is MB8 used for?
- laptop/phone housings
- welded panels
- thin-gauge stampings
Advantages
- Ductile — tolerates forming and impact — 18%, better than 95% of magnesium alloy grades
- Readily welded — 85/100, better than 94% of magnesium alloy grades
- Forms and bends easily — 45/100, better than 94% of magnesium alloy grades
- Conducts heat well — 125 W/m·K (72.2 BTU/hr·ft·°F), better than 91% of magnesium alloy grades
- High service temperature — 200°C (392 °F), better than 84% of magnesium alloy grades
MB8 properties
Typical room-temperature values for MB8-M; bars are the position among magnesium alloy grades.
Physical3
MB8 has a density of 1.78 g/cm³ (0.0643 lb/in³), lighter than 78% of magnesium alloy grades. It melts at 645°C (1,193 °F).
Mechanical15
MB8 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 61% of magnesium alloy grades. Elongation at break is 18% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
MB8 is rated for continuous service to 200°C (392 °F). It conducts heat at 125 W/m·K (72.2 BTU/hr·ft·°F), better than 91% of magnesium alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
MB8 conducts electricity at 25 % IACS, better than 69% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 64% of magnesium alloy grades.
Sustainability4
Producing a kilogram of MB8 takes about 340 MJ of energy and emits 32 kg of CO₂ — more than 59% of magnesium alloy grades. Typical recycled content is 10%.
Manufacturability7
MB8's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability excellent (85/100); formability fair (45/100).
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. MB8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with MB8
Is MB8 easy to machine?
Extremely free-cutting with high speeds, sharp positive-rake tools and no water-based coolant on fine chips; collect and control swarf as it is a fire hazard.
Can MB8 be welded?
Excellent TIG/MIG weldability with AZ61/AZ92 or matching Mg-Mn filler under argon; being Al-free it needs no post-weld stress-relief against chloride SCC.
Can MB8 be formed, bent or molded?
Cold forming is limited by the HCP structure — bend, draw and stretch at 250–350 °C with heated tooling, then air cool.
MB8 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 |
|---|---|---|
| Mnprincipal strengthening/refining addition | 1.3 – 2.2 | 1.8 |
| Ceadded as mischmetal; improves elevated-temperature strength and texture | 0.15 – 0.35 | 0.25 |
| Alimpurity limit | ≤ 0.2 | |
| Znimpurity limit | ≤ 0.3 | |
| Siimpurity limit | ≤ 0.1 | |
| Cuimpurity limit | ≤ 0.05 | |
| Feimpurity limit; controls corrosion rate | ≤ 0.05 | |
| Niimpurity limit; controls corrosion rate | ≤ 0.01 | |
| Others (each)total ≤ 0.30 | ≤ 0.1 | |
| Mg | balance |
What surface finishes work on MB8?
Use chromate-free phosphate-permanganate or MAO/HAE conversion coatings followed by epoxy primer and topcoat; direct plating requires a zincate-type intermediate.
Equivalent designations
Standards and trade names that resolve to Magnesium Alloy MB8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- AZ31C
How much does MB8 cost?
MB8 is a high-cost magnesium alloy ($$$$), pricier than about 78% 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.
MB8 — frequently asked
What is MB8 used for?
MB8 is typically used for laptop/phone housings, welded panels and thin-gauge stampings. In short: best-forming wrought magnesium here; no post-weld stress relief; 200 °C service ceiling.
What is the yield strength of MB8?
MB8 has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 61% of magnesium alloy grades. Strength varies by condition: see the 5 listed tempers.
Is MB8 easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Extremely free-cutting with high speeds, sharp positive-rake tools and no water-based coolant on fine chips; collect and control swarf as it is a fire hazard.
Can MB8 be welded?
Yes — weldability is rated excellent (85/100). Excellent TIG/MIG weldability with AZ61/AZ92 or matching Mg-Mn filler under argon; being Al-free it needs no post-weld stress-relief against chloride SCC.
What surface finishes work on MB8?
Use chromate-free phosphate-permanganate or MAO/HAE conversion coatings followed by epoxy primer and topcoat; direct plating requires a zincate-type intermediate.
Can MB8 be formed, bent or molded?
Cold forming is limited by the HCP structure — bend, draw and stretch at 250–350 °C with heated tooling, then air cool.
What is the maximum service temperature of MB8?
MB8 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between MB8-M and MB8-Y?
M is the default condition — most commonly stocked sheet condition — maximum ductility for warm forming, deep drawing and welded assemblies. Y: highest strength / flattest thin-gauge sheet; choose for flat stiff panels that will not be formed. Yield strength is 140 MPa in M versus 200 MPa in Y.
How much does MB8 cost?
MB8 is a high-cost magnesium alloy ($$$$), pricier than about 78% 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
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Magnesium) — ASM International (1990)
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.