Aluminum LM6-M
Heat-treated state
BS LM6
M = thermomechanically controlled processed
The formal BS 1490 designation LM6-M; identical in practice to the F condition and the only condition registered for LM6.
Values for the M condition
Other LM6 tempers and conditions
LM6 is listed in 5 conditions; see the grade overview at LM6.
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 |
MThis page 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-M?
LM6-M is LM6 heat treated to M — the formal BS 1490 designation LM6-M; identical in practice to the F condition and the only condition registered for LM6. LM6-M 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). LM6-M 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). F is the default condition FabDigit quotes; M is available on request or by drawing note.
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-M properties
Typical room-temperature values for LM6-M; 19 are specific to this condition. Other listed values are LM6 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
LM6-M 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-M 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-M 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-M 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-M 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-M's machinability is fair (40/100, worse than 81% of aluminum grades); weldability very good (80/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with LM6-M
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.
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.
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 | — |
LM6-M — frequently asked
What is LM6-M used for?
LM6-M 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-M?
LM6-M 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-M 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-M 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-M?
Anodising gives a dark grey, streaky film — prefer chromate conversion, powder coat or paint; hard anodise only where wear resistance outweighs appearance.
Can LM6-M 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-M?
LM6-M 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.
Can FabDigit make parts in LM6-M?
Yes — LM6-M 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.