Aluminum LM6
BS LM6
LM6 is a British-standard (BS 1490) eutectic aluminium–silicon casting alloy with ~11–13 % Si, essentially identical to EN AC-44100 (AlSi12) and close to US A413/443 die-casting alloys.
Values for the F condition
LM6 tempers and conditions
LM6 is supplied in 5 conditions, soft to hard. F 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 |
|---|---|---|---|---|---|---|
Sand cast, as cast | Slow-cooled sand castings — coarser eutectic, lowest strength but the cheapest route for large or low-volume parts. | 65 | 160 | 5 | 50 HB | 37 % IACS |
FDefault As fabricated | Standard supply condition for LM6; the alloy is not heat-treatable, so nearly all parts ship as cast. | 70 | 170 | 6 | 52 HB | 33 % IACS |
Thermomechanically controlled processed | The formal BS 1490 designation LM6-M; identical in practice to the F condition and the only condition registered for LM6. | 70 | 170 | 6 | 52 HB | 33 % IACS |
Chill / gravity die cast, as cast | Faster solidification in a permanent mould refines the eutectic, raising strength and ductility over sand casting. | 80 | 190 | 8 | 58 HB | 35 % IACS |
High-pressure die cast, as cast | Pressure die casting gives the finest structure and by far the highest strength, at the cost of low ductility and porosity-limited weldability/heat treatment. | 145 | 290 | 2.5 | 80 HB | 31 % IACS |
What is LM6?
LM6 is a British-standard (BS 1490) eutectic aluminium–silicon casting alloy with ~11–13 % Si, essentially identical to EN AC-44100 (AlSi12) and close to US A413/443 die-casting alloys. Its eutectic composition gives outstanding fluidity, low shrinkage, pressure tightness and very good seawater corrosion resistance, so it is the default choice for thin-walled, intricate sand, gravity-die and pressure die castings such as pump bodies, marine fittings and housings. It is not heat-treatable, so strength stays modest (~160–200 MPa as cast), the high silicon makes machining abrasive and anodising dark and patchy. LM6 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 90% of aluminum grades. It melts at 574°C (1,065 °F). LM6 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 92% of aluminum grades. Elongation at break is 6% and the elastic modulus is 71 GPa (10.3 Msi).
What is LM6 used for?
- Marine castings and fittings
- Pump bodies
- Thin-walled housings and covers
- Motor and gearbox casings
- Water-carrying manifolds and fittings
- Electrical enclosures
- Intricate cored sand castings
Limitations
- Hard to polish — 35/100, worse than 98% of aluminum grades
- Limited formability — 5/100, worse than 94% of aluminum grades
- Low strength — 70 MPa (10.2 ksi), worse than 92% of aluminum grades
- Low fracture toughness — 16 MPa·√m (14.6 ksi·√in), worse than 89% of aluminum grades
- Difficult to machine — 40/100, worse than 81% of aluminum grades
LM6 properties
Typical room-temperature values for LM6-F; bars are the position among aluminum grades.
Physical3
LM6 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 90% of aluminum grades. It melts at 574°C (1,065 °F).
Mechanical13
LM6 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 92% of aluminum grades. Elongation at break is 6% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
LM6 is rated for continuous service to 150°C (302 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), worse than 65% of aluminum grades. Thermal expansion is 20.4 µm/m·K (11.3 µin/in·°F).
Electrical3
LM6 conducts electricity at 33 % IACS, worse than 57% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 67% of aluminum grades.
Sustainability4
Producing a kilogram of LM6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 70%.
Manufacturability8
LM6's machinability is fair (40/100, worse than 81% of aluminum grades); weldability very good (80/100); formability not recommended (5/100).
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. LM6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with LM6
Is LM6 easy to machine?
Abrasive eutectic silicon — use polished-flute PCD or uncoated carbide tooling, high speed, low feed and flood coolant; expect built-up edge with HSS.
Can LM6 be welded?
Readily TIG/MIG welded with 4043 or 4047 filler; preheat 150–200 °C on heavy sections and avoid welding gassy high-pressure die castings.
Can LM6 be formed, bent or molded?
Excellent fluidity and low shrinkage for thin walls and intricate cores in sand, gravity-die and pressure die casting; modify with Na or Sr and degas the melt to avoid coarse Si and porosity.
Manufacturability
The process limits FabDigit applies to LM6. Every LM6 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair40 / 100 |
|---|---|
| ISO material group | N.1 |
| Cutting speed (rough / finish) | 350 / 420 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
LM6 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 |
|---|---|---|
| Sieutectic silicon; Na/Sr modified for ductility | 10 – 13 | 11.5 |
| Fe0.6 max sand/chill; higher tolerated in die casting | ≤ 0.6 | 0.35 |
| Cukept low for corrosion resistance | ≤ 0.1 | 0.05 |
| Mn | ≤ 0.5 | 0.2 |
| Mg | ≤ 0.1 | 0.03 |
| Ni | ≤ 0.1 | 0.03 |
| Zn | ≤ 0.1 | 0.05 |
| Pb | ≤ 0.1 | |
| Sn | ≤ 0.05 | |
| Tigrain refiner residual | ≤ 0.2 | 0.05 |
| Others (each)total 0.15 max | ≤ 0.05 | |
| Al | balance |
What surface finishes work on LM6?
Anodising gives a dark grey, streaky film — prefer chromate conversion, powder coat or paint; hard anodise 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).
Passivation
Conversion Coating
PVD Coating
Equivalent designations
Standards and trade names that resolve to Aluminum LM6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- BS
- 1490 LM6
How much does LM6 cost?
LM6 is a budget-cost aluminum ($), cheaper than about 99% 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.
LM6 — frequently asked
What is LM6 used for?
LM6 is typically used for marine castings and fittings, pump bodies, thin-walled housings and covers, motor and gearbox casings, water-carrying manifolds and fittings and electrical enclosures. In short: eutectic Al-Si; excellent castability and corrosion resistance.
What is the yield strength of LM6?
LM6 has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 92% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is LM6 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of aluminum grades). Abrasive eutectic silicon — use polished-flute PCD or uncoated carbide tooling, high speed, low feed and flood coolant; expect built-up edge with HSS.
Can LM6 be welded?
Yes — weldability is rated very good (80/100). Readily TIG/MIG welded with 4043 or 4047 filler; preheat 150–200 °C on heavy sections and avoid welding gassy high-pressure die castings.
What surface finishes work on LM6?
Anodising gives a dark grey, streaky film — prefer chromate conversion, powder coat or paint; hard anodise only where wear resistance outweighs appearance.
Can LM6 be formed, bent or molded?
Excellent fluidity and low shrinkage for thin walls and intricate cores in sand, gravity-die and pressure die casting; modify with Na or Sr and degas the melt to avoid coarse Si and porosity.
What is the maximum service temperature of LM6?
LM6 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 LM6-F and LM6 HPDC-F?
F is the default condition — standard supply condition for LM6; the alloy is not heat-treatable, so nearly all parts ship as cast. HPDC-F: pressure die casting gives the finest structure and by far the highest strength, at the cost of low ductility and porosity-limited weldability/heat treatment. Yield strength is 70 MPa in F versus 145 MPa in HPDC-F.
How much does LM6 cost?
LM6 is a budget-cost aluminum ($), cheaper than about 99% 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.
Can FabDigit make parts in LM6?
Yes — LM6 is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- BS 1490: Aluminium and aluminium alloy ingots and castings for general engineering purposes — BSI (1988)
- BS EN 1706: Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties (AC-44100) — CEN (2020)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (A413.0/A443.0 data) — ASM International (1990)
- ASTM B85 / B26 — Aluminum-Alloy Die Castings and Sand Castings — ASTM (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.