Aluminum LM27-T7
Temper
BS LM27
T7 = 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).
Values for the T7 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 |
T7This page 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 |
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-T7?
LM27-T7 is LM27 in the T7 temper — use when dimensional and thermal stability at elevated service temperature matters more than peak strength (e.g. heated housings). LM27-T7 has a yield strength of 155 MPa (22.5 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 63% of aluminum grades. Elongation at break is 3% and the elastic modulus is 74 GPa (10.7 Msi). LM27-T7 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; T7 is available on request or by drawing note.
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
Limitations
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Poor heat conductor — 112 W/m·K (64.7 BTU/hr·ft·°F), worse than 86% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
- Low electrical conductivity — 28 % IACS, worse than 82% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
LM27-T7 properties
Typical room-temperature values for LM27-T7; 10 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-T7 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-T7 has a yield strength of 155 MPa (22.5 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 63% of aluminum grades. Elongation at break is 3% and the elastic modulus is 74 GPa (10.7 Msi).
Thermal6
LM27-T7 is rated for continuous service to 200°C (392 °F). It conducts heat at 112 W/m·K (64.7 BTU/hr·ft·°F), worse than 86% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
LM27-T7 conducts electricity at 28 % IACS, worse than 82% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 75% of aluminum grades.
Sustainability4
Producing a kilogram of LM27-T7 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-T7's machinability is good (68/100, better than 67% 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-T7
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-T7 — frequently asked
What is LM27-T7 used for?
LM27-T7 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-T7?
LM27-T7 has a typical yield strength of 155 MPa (22.5 ksi) and a tensile strength of 225 MPa (32.6 ksi) — weaker than 63% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is LM27-T7 easy to machine?
Reasonably — machinability is rated good (68/100, better than 67% 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-T7 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-T7?
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-T7 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-T7?
LM27-T7 is rated for continuous use to about 200°C (392 °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.