Aluminum LM9
BS LM9
LM9 is a British Standard AlSi12Mg casting alloy comparable to ASTM 360.0, combining a near-eutectic silicon content with a magnesium addition that allows TE, TB7 and TF heat treatment.
Reference datasheet — LM9 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
LM9 tempers and conditions
LM9 is supplied in 6 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M | Sand-cast as-cast condition; slower solidification coarsens the eutectic so strength is 10–15% below chill castings. | 90 | 170 | 2 | 55 HB | 24 % IACS |
MDefault Thermomechanically controlled processed | Standard as-cast condition; pick for thin-wall pressure-tight parts where ductility and cost matter more than strength. | 95 | 190 | 3 | 60 HB | 25 % IACS |
Solution treated and stabilised | Solution treat + stabilise for maximum dimensional stability and better ductility than fully aged tempers. | 140 | 235 | 4 | 75 HB | 26 % IACS |
Precipitation (artificially aged) from as-cast | Simple low-temperature age (~155–170 °C) that raises hardness and proof stress without solution treatment distortion. | 200 | 275 | 1.5 | 100 HB | 28 % IACS |
TF | Fully heat-treated sand castings; strength slightly below chill-cast TF because of coarser structure. | 230 | 295 | 1 | 100 HB | 29 % IACS |
Solution treated and fully artificially aged | Full T6-type treatment for highest strength and hardness; accept very low elongation and possible quench distortion. | 240 | 310 | 1.5 | 110 HB | 30 % IACS |
What is LM9?
LM9 is a British Standard AlSi12Mg casting alloy comparable to ASTM 360.0, combining a near-eutectic silicon content with a magnesium addition that allows TE, TB7 and TF heat treatment. It is used for thin-wall pressure die, gravity die and sand castings, giving 95 MPa yield, 190 MPa tensile, 3% elongation, 60 HB and 142 W/m·K in the default condition. Strength is moderate and service is limited to about 150 °C; machinability is low (45) because of the abrasive eutectic silicon, so LM16/355.0 is the better choice when higher strength and easier machining are required. LM9 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 90% of aluminum grades. It melts at 557°C (1,035 °F). LM9 has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 190 MPa (27.6 ksi) — weaker than 86% of aluminum grades. Elongation at break is 3% and the elastic modulus is 71 GPa (10.3 Msi).
What is LM9 used for?
- Die-cast housings
- Automotive components
- Thin-wall covers and end caps
- Pump and gearbox casings
- Electrical enclosures
- Manifolds and brackets
Limitations
- Low electrical conductivity — 25 % IACS, worse than 92% of aluminum grades
- Low strength — 95 MPa (13.8 ksi), worse than 86% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
- Limited formability — 10/100, worse than 80% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
LM9 properties
Typical room-temperature values for LM9-M; bars are the position among aluminum grades.
Physical3
LM9 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 90% of aluminum grades. It melts at 557°C (1,035 °F).
Mechanical13
LM9 has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 190 MPa (27.6 ksi) — weaker than 86% of aluminum grades. Elongation at break is 3% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
LM9 is rated for continuous service to 150°C (302 °F). It conducts heat at 142 W/m·K (82 BTU/hr·ft·°F), better than 51% of aluminum grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
LM9 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 LM9 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 80%.
Manufacturability8
LM9's machinability is fair (45/100, worse than 72% of aluminum grades); weldability very good (72/100); formability not recommended (10/100).
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. LM9 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with LM9
Is LM9 easy to machine?
Machinable with PCD or coated-carbide tooling at high speed and generous coolant; free eutectic silicon is abrasive and rapidly wears HSS.
Can LM9 be welded?
Readily TIG/MIG welded with 4047 or 4043 filler; preheat 150–200 °C on thick sections and re-age afterwards to recover TE/TF strength.
Can LM9 be formed, bent or molded?
Foundry alloy only — excellent fluidity and low hot-tearing suit thin-wall gravity die, sand and pressure die casting; not cold-formable.
LM9 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 |
|---|---|---|
| Sinear-eutectic, gives fluidity | 10 – 13 | 11.5 |
| MgMg2Si age-hardening | 0.2 – 0.6 | 0.4 |
| Mnneutralises Fe needles | 0.3 – 0.7 | 0.5 |
| Feup to 1.0 % permitted for pressure die castings | ≤ 0.6 | 0.4 |
| Cukept low for corrosion resistance | ≤ 0.1 | 0.05 |
| Ni | ≤ 0.1 | |
| Zn | ≤ 0.1 | |
| Tigrain refinement | ≤ 0.2 | 0.1 |
| Pb | ≤ 0.1 | |
| Sn | ≤ 0.05 | |
| Other (each) | ≤ 0.05 | |
| Al | balance |
What surface finishes work on LM9?
Takes chromate conversion coating, powder coat and paint well; conventional anodizing gives a dark, blotchy grey, so hard-anodize only where wear resistance outweighs appearance.
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 LM9 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 360.0
How much does LM9 cost?
LM9 is a standard-cost aluminum ($$), cheaper than about 71% 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.
LM9 — frequently asked
What is LM9 used for?
LM9 is typically used for die-cast housings, automotive components, thin-wall covers and end caps, pump and gearbox casings, electrical enclosures and manifolds and brackets. In short: thin-wall die-casting alloy; heat-treatable AlSi12; abrasive to tooling.
What is the yield strength of LM9?
LM9 has a typical yield strength of 95 MPa (13.8 ksi) and a tensile strength of 190 MPa (27.6 ksi) — weaker than 86% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is LM9 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Machinable with PCD or coated-carbide tooling at high speed and generous coolant; free eutectic silicon is abrasive and rapidly wears HSS.
Can LM9 be welded?
Yes — weldability is rated very good (72/100). Readily TIG/MIG welded with 4047 or 4043 filler; preheat 150–200 °C on thick sections and re-age afterwards to recover TE/TF strength.
What surface finishes work on LM9?
Takes chromate conversion coating, powder coat and paint well; conventional anodizing gives a dark, blotchy grey, so hard-anodize only where wear resistance outweighs appearance.
Can LM9 be formed, bent or molded?
Foundry alloy only — excellent fluidity and low hot-tearing suit thin-wall gravity die, sand and pressure die casting; not cold-formable.
What is the maximum service temperature of LM9?
LM9 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between LM9-M and LM9-TF?
M is the default condition — standard as-cast condition; pick for thin-wall pressure-tight parts where ductility and cost matter more than strength. TF: full T6-type treatment for highest strength and hardness; accept very low elongation and possible quench distortion. Yield strength is 95 MPa in M versus 240 MPa in TF.
How much does LM9 cost?
LM9 is a standard-cost aluminum ($$), cheaper than about 71% 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
- BS 1490 — Aluminium and aluminium alloy ingots and castings — BSI (1988)
- ASTM B85 / B108 (360.0, A360.0 die and permanent-mold castings) — ASTM (2021)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- EN 1706 — EN AC-43400 (AlSi10Mg(Fe)) / AlSi12Mg comparison data — CEN (2020)
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.