Aluminum LM27-T6
Temper
BS LM27
T6 = solution heat treated and artificially aged
Peak-strength condition (319.0-T6 practice) for highly loaded structural castings; expect some distortion/quench stress and reduced conductivity.
Values for the T6 condition
Other LM27 tempers and conditions
LM27 is listed in 4 conditions; see the grade overview at LM27.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Default stocked condition: general engineering sand or gravity-die castings where no heat treatment is applied. | 110 | 180 | 2 | 80 HB | 27 % IACS |
Solution heat treated and overaged (stabilized) | Use when dimensional and thermal stability at elevated service temperature matters more than peak strength (e.g. heated housings). | 155 | 225 | 3 | 80 HB | 28 % IACS |
T6This page Solution heat treated and artificially aged | Peak-strength condition (319.0-T6 practice) for highly loaded structural castings; expect some distortion/quench stress and reduced conductivity. | 180 | 255 | 2 | 92 HB | 25 % IACS |
Precipitation (artificially aged) treated from the as-cast condition | Choose when higher proof stress, hardness and dimensional stability are needed without the distortion risk of a full solution treatment. | 185 | 215 | 1 | 105 HB | 26 % IACS |
What is LM27-T6?
LM27-T6 is LM27 in the T6 temper — peak-strength condition (319.0-T6 practice) for highly loaded structural castings; expect some distortion/quench stress and reduced conductivity. LM27-T6 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 54% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi). LM27-T6 has a density of 2.76 g/cm³ (0.0997 lb/in³), heavier than 70% of aluminum grades. It melts at 520°C (968 °F). M is the default condition FabDigit quotes; T6 is available on request or by drawing note.
Advantages
- High service temperature — 175°C (347 °F), better than 83% of aluminum grades
- Easy to machine — 72/100, better than 80% of aluminum grades
Limitations
- Poor heat conductor — 103 W/m·K (59.5 BTU/hr·ft·°F), worse than 92% of aluminum grades
- Low electrical conductivity — 25 % IACS, worse than 92% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Limited ductility — 2%, worse than 87% of aluminum grades
- Needs corrosion protection — 38/100, worse than 79% of aluminum grades
LM27-T6 properties
Typical room-temperature values for LM27-T6; 12 are specific to this condition. Other listed values are LM27 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
LM27-T6 has a density of 2.76 g/cm³ (0.0997 lb/in³), heavier than 70% of aluminum grades. It melts at 520°C (968 °F).
Mechanical14
LM27-T6 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 54% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi).
Thermal6
LM27-T6 is rated for continuous service to 175°C (347 °F). It conducts heat at 103 W/m·K (59.5 BTU/hr·ft·°F), worse than 92% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
LM27-T6 conducts electricity at 25 % IACS, worse than 92% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 79% of aluminum grades.
Sustainability4
Producing a kilogram of LM27-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 90%.
Manufacturability7
LM27-T6's machinability is very good (72/100, better than 80% of aluminum grades); weldability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with LM27-T6
Is LM27 easy to machine?
Machines well with the Cu phase breaking chips; use polycrystalline-diamond or coated carbide at high speed because primary/eutectic Si is abrasive, and flood coolant to avoid built-up edge.
Can LM27 be welded?
TIG/MIG repair welding is possible with 4043/4047 filler and preheat 150–200 °C, but the ~2 % Cu makes it hot-crack sensitive — not recommended for structural weldments.
Can LM27 be formed, bent or molded?
Excellent foundry alloy: good fluidity, low hot-tearing, pressure-tight sections; suits sand, gravity and low-pressure die casting with chills or directional solidification for thick sections.
What surface finishes work on LM27?
Decorative anodising is poor (grey mottled); prefer chromate/chrome-free conversion coating plus primer/powder coat, or hard anodise / electroless nickel where wear resistance is needed; impregnation can be used to seal porosity.
LM27 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 |
|---|---|---|
| Si | 6 – 8 | 7 |
| Cu | 1.5 – 2.5 | 2 |
| Mn | 0.2 – 0.6 | 0.4 |
| Mgmax only | ≤ 0.35 | 0.15 |
| Feimpurity max | ≤ 0.8 | 0.6 |
| Nimax only | ≤ 0.3 | — |
| Znmax only | ≤ 1 | — |
| Pbmax only | ≤ 0.2 | — |
| Snmax only | ≤ 0.1 | — |
| Tigrain refiner, max | ≤ 0.2 | 0.1 |
| Al | balance | — |
LM27-T6 — frequently asked
What is LM27-T6 used for?
LM27-T6 is typically used for cylinder heads, housings and casings, engine blocks and crankcases, gearbox and pump bodies, manifolds and general engineering brackets and covers. In short: low-cost general-purpose casting; good machinability, copper-bearing; lower corrosion resistance.
What is the yield strength of LM27-T6?
LM27-T6 has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 54% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is LM27-T6 easy to machine?
Yes — machinability is rated very good (72/100, better than 80% of aluminum grades). Machines well with the Cu phase breaking chips; use polycrystalline-diamond or coated carbide at high speed because primary/eutectic Si is abrasive, and flood coolant to avoid built-up edge.
Can LM27-T6 be welded?
With care — weldability is rated fair (40/100). TIG/MIG repair welding is possible with 4043/4047 filler and preheat 150–200 °C, but the ~2 % Cu makes it hot-crack sensitive — not recommended for structural weldments.
What surface finishes work on LM27-T6?
Decorative anodising is poor (grey mottled); prefer chromate/chrome-free conversion coating plus primer/powder coat, or hard anodise / electroless nickel where wear resistance is needed; impregnation can be used to seal porosity.
Can LM27-T6 be formed, bent or molded?
Excellent foundry alloy: good fluidity, low hot-tearing, pressure-tight sections; suits sand, gravity and low-pressure die casting with chills or directional solidification for thick sections.
What is the maximum service temperature of LM27-T6?
LM27-T6 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between LM27-M and LM27-TE?
M is the default condition — default stocked condition: general engineering sand or gravity-die castings where no heat treatment is applied. TE: choose when higher proof stress, hardness and dimensional stability are needed without the distortion risk of a full solution treatment. Yield strength is 110 MPa in M versus 185 MPa in TE.
Sources
- BS 1490: Aluminium and aluminium alloy ingots and castings for general engineering purposes — BSI (1988)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (319.0 data) — ASM International (1990)
- Aluminum Association Teal Sheets — Registration Record of Casting Alloys — The Aluminum Association (2015)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- ASTM B26/B26M & B108 — Aluminum-Alloy Sand and Permanent Mold Castings — ASTM (2022)
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.