Aluminium Casting Alloy LM5
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LM5 ALUMINIUM CASTING ALLOY OVERVIEW
This alloy complies with the BS 1490:1988 LM5 standard.
CHEMICAL MAKEUP
| % | % | % | |||
|---|---|---|---|---|---|
| Copper | 0.1 max | Magnesium | 3.0-6.0 | Silicon | 0.3 max |
| Iron | 0.6 max | Manganese | 0.3-0.7 | Nickel | 0.1 max |
| Zinc | 0.1 max | Lead | 0.5 max | Tin | 0.05 max |
| Titanium | 0.2 max | Aluminium | Remainder | Others each | 0.5 max |
| Others total | 0.15 max |
MECHANICAL PERFORMANCE OF LM5 ALUMINIUM CASTINGS
| SAND CASTING | GRAVITY DIE CAST | |
|---|---|---|
| 0.2% Proof Stress (N/mm²) | 90-110 | 90-120 |
| Tensile Strength (N/mm²) | 140-170 | 170-280 |
| Elongation (%) | 3 | 5 |
| Impact resistance Izod (Nm) | 7.9 | 12.6 |
| Brinell Hardness | 50-70 | 60-70 |
| Modulus of Elasticity (×10³ N/mm²) | 71 | 71 |
| Shear Strength (N/mm²) | 140 | - |
BEHAVIOUR AT HIGHER TEMPERATURES
Room-temperature characteristics remain mostly stable up to around 200°C, but show a sharp decline once temperatures rise past roughly 300°C.
LM5 PHYSICAL CHARACTERISTICS
| Coefficient of Thermal Expansion (per °C @ 20–100°C) | 0.000023 |
| Thermal conductivity (cal/cm²/cm/°C @ 25°C) | 0.33 |
| Electrical conductivity (% copper standard @ 20°C) | 31.0 |
| Density (g/cm³) | 2.65 |
| Freezing range (°C) approx. | 12 |
PERFORMANCE UNDER ELEVATED HEAT
The alloy retains most properties up to approximately 200°C, with a rapid drop-off occurring beyond 300°C.
GENERAL PHYSICAL DATA
| Coefficient of Thermal Expansion (per C @ 20-100C) | 0.000023 |
| Thermal counducivity (cal/cm2/cm/C @ 25C) | 0.33 |
| Electrical conductivity (% copper standard @ 20C) | 31.0 |
| Density (g/cm3) | 2.65 |
| Freezing range (C) approx. | 642-580 |
MACHINING QUALITIES
LM5 machines cleanly and is capable of taking a very fine polish.
RESISTANCE TO CORROSION
LM5 demonstrates strong corrosion resistance in a wide range of environments and is considered one of the most marine-durable aluminium alloys.
ANODISING SUITABILITY
LM5 responds well to standard anodising techniques, producing a clear, colourless film that bonds effectively and works well for decorative finishes.
USES AND PRACTICAL NOTES
LM5 is chosen where outstanding corrosion resistance is essential—particularly in contact with seawater or marine atmospheres. It is widely used for equipment in food handling, cooking systems, chemical plants, and applications that require an aluminium casting with a smooth, polished surface.
Common examples include door hardware, vehicle trim, decorative components, and smaller castings where a clear anodised finish is desired.
LM5 is primarily used for sand castings and, to a lesser degree, gravity die castings. It is also suitable for simple-shaped high-pressure die castings. The alloy is supplied in a non-heat-treated condition.