Aluminum 5A12
GB 5A12
5A12 (LF12) is a very high magnesium (about 8-9% Mg) non-heat-treatable Al-Mg wrought alloy used where specific strength outweighs ease of fabrication.
Reference datasheet — 5A12 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 O condition
5A12 tempers and conditions
5A12 is supplied in 5 conditions, soft to hard. O 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 |
|---|---|---|---|---|---|---|
As fabricated | Forging stock, billet and rough extrusion supplied without guaranteed mechanical properties, for subsequent working and annealing. | 205 | 395 | 15 | 95 HB | 25 % IACS |
ODefault Annealed | Most commonly stocked condition: maximum ductility for forming, bending and welding of high-Mg sheet/plate. | 210 | 400 | 18 | 95 HB | 25 % IACS |
Strain hardened from hot working only | Thick plate and extruded shapes supplied as hot-worked with guaranteed properties; used for machined aerospace structural parts. | 230 | 410 | 15 | 100 HB | 25 % IACS |
Strain hardened, half hard | Cold-rolled half-hard sheet when higher strength and stiffness of thin skins is needed and only mild forming is required. | 350 | 460 | 8 | 120 HB | — |
Strain hardened, full hard | Fully cold-worked strip/sheet for flat, high-strength, non-formed parts; lowest ductility and highest SCC sensitivity. | 440 | 520 | 4 | 140 HB | 24 % IACS |
What is 5A12?
5A12 (LF12) is a very high magnesium (about 8-9% Mg) non-heat-treatable Al-Mg wrought alloy used where specific strength outweighs ease of fabrication. It provides 210 MPa yield, 400 MPa tensile, 18% elongation and HB 95 in sheet and plate for aerospace structures and high-strength welded assemblies. Formability is only 65, corrosion resistance 62, electrical conductivity 25% IACS, thermal conductivity 105 W/m·K, and service must stay at or below 65 °C; availability is limited, so 5A06 is the usual fallback. 5A12 has a density of 2.6 g/cm³ (0.0939 lb/in³), lighter than 97% of aluminum grades. It melts at 565°C (1,049 °F). 5A12 has a yield strength of 210 MPa (30.5 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 56% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi).
What is 5A12 used for?
- Aerospace structural components
- High-strength welded assemblies
- Airframe sheet and plate parts
- Welded frames and brackets
- Riveted structural fittings
- Highly loaded lightweight covers
Advantages
- Ductile — tolerates forming and impact — 18%, better than 86% of aluminum grades
- Forms and bends easily — 65/100, better than 80% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 97% of aluminum grades
- Low electrical conductivity — 25 % IACS, worse than 92% of aluminum grades
- Poor heat conductor — 105 W/m·K (60.7 BTU/hr·ft·°F), worse than 91% of aluminum grades
- Difficult to machine — 42/100, worse than 77% of aluminum grades
5A12 properties
Typical room-temperature values for 5A12-O; bars are the position among aluminum grades.
Physical3
5A12 has a density of 2.6 g/cm³ (0.0939 lb/in³), lighter than 97% of aluminum grades. It melts at 565°C (1,049 °F).
Mechanical13
5A12 has a yield strength of 210 MPa (30.5 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 56% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
5A12 is rated for continuous service to 65°C (149 °F). It conducts heat at 105 W/m·K (60.7 BTU/hr·ft·°F), worse than 91% of aluminum grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical3
5A12 conducts electricity at 25 % IACS, worse than 92% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 67% of aluminum grades.
Sustainability4
Producing a kilogram of 5A12 takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 20%.
Manufacturability8
5A12's machinability is fair (42/100, worse than 77% of aluminum grades); weldability very good (72/100); formability good (65/100).
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 aluminum family
Yield strength against density for every aluminum grade FabDigit runs. 5A12 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 5A12
Is 5A12 easy to machine?
Machine with sharp polished-flute carbide tools, high rake, high speed and generous flood coolant/lubricant; annealed material is gummy and forms built-up edge, cold-worked tempers cut cleaner.
Can 5A12 be welded?
Readily GTAW/GMAW welded with 5356 or 5556 (high-Mg) filler under clean argon; avoid 4000 series Si fillers (brittle Mg2Si) and keep interpass temperature low to limit sensitization; as-welded HAZ strength ≈ O temper.
Can 5A12 be formed, bent or molded?
Form in the O temper — the alloy work-hardens very fast; use generous bend radii (≥2–3 t), warm forming 200–250 °C for severe shapes, and intermediate anneal ~340–380 °C with slow cool.
5A12 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 |
|---|---|---|
| Mgprimary solid-solution strengthener | 8.3 – 9.6 | 9 |
| Mngrain-structure control | 0.4 – 0.8 | 0.6 |
| Tigrain refiner | 0.05 – 0.15 | 0.1 |
| Siimpurity | ≤ 0.3 | |
| Feimpurity | ≤ 0.3 | |
| Cuimpurity | ≤ 0.05 | |
| Znimpurity | ≤ 0.2 | |
| Bemelt oxidation control (optional addition) | ≤ 0.01 | 0 |
| Others (each) | ≤ 0.05 | |
| Others (total) | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 5A12?
Responds well to clear sulphuric/chromic anodizing and chromate/trivalent conversion coatings; alkaline etch times must be short because of high Mg; not furnace-brazeable, mechanical polish then anodize for decorative finish.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum 5A12 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GB (China)
- LF12
How much does 5A12 cost?
5A12 is a premium-cost aluminum ($$$), 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.
5A12 — frequently asked
What is 5A12 used for?
5A12 is typically used for aerospace structural components, high-strength welded assemblies, airframe sheet and plate parts, welded frames and brackets, riveted structural fittings and highly loaded lightweight covers. In short: highest-strength Al-Mg grade; hardest 5000 series in library; limited availability, low formability.
What is the yield strength of 5A12?
5A12 has a typical yield strength of 210 MPa (30.5 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 56% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 5A12 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 77% of aluminum grades). Machine with sharp polished-flute carbide tools, high rake, high speed and generous flood coolant/lubricant; annealed material is gummy and forms built-up edge, cold-worked tempers cut cleaner.
Can 5A12 be welded?
Yes — weldability is rated very good (72/100). Readily GTAW/GMAW welded with 5356 or 5556 (high-Mg) filler under clean argon; avoid 4000 series Si fillers (brittle Mg2Si) and keep interpass temperature low to limit sensitization; as-welded HAZ strength ≈ O temper.
What surface finishes work on 5A12?
Responds well to clear sulphuric/chromic anodizing and chromate/trivalent conversion coatings; alkaline etch times must be short because of high Mg; not furnace-brazeable, mechanical polish then anodize for decorative finish.
Can 5A12 be formed, bent or molded?
Form in the O temper — the alloy work-hardens very fast; use generous bend radii (≥2–3 t), warm forming 200–250 °C for severe shapes, and intermediate anneal ~340–380 °C with slow cool.
What is the maximum service temperature of 5A12?
5A12 is rated for continuous use to about 65°C (149 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 5A12-O and 5A12-H18?
O is the default condition — most commonly stocked condition: maximum ductility for forming, bending and welding of high-Mg sheet/plate. H18: fully cold-worked strip/sheet for flat, high-strength, non-formed parts; lowest ductility and highest SCC sensitivity. Yield strength is 210 MPa in O versus 440 MPa in H18.
How much does 5A12 cost?
5A12 is a premium-cost aluminum ($$$), 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
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B: Corrosion — Materials (Al-Mg sensitization/SCC) — ASM International (2005)
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.