Aluminium Casting Alloy LM16
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LM16 ALUMINIUM CASTING ALLOY SUMMARY
This alloy conforms to BS 1490:1988 LM16. Castings are supplied in the solution-treated and naturally aged (TB) state or in the fully heat-treated (TF) condition.
CHEMICAL MAKEUP
| % | % | % | |||
|---|---|---|---|---|---|
| Magnesium | 0.4–0.6 | Copper | 1.0–1.5 | Iron | 0.6 max |
| Silicon | 4.5–5.5 | Nickel | 0.25 max | Manganese | 0.5 max |
| Lead | 0.1 max | Zinc | 0.1 max | Titanium | 0.2 max |
| Tin | 0.05 | Other each | 0.05 max | ||
| Others total | 0.15 max | Aluminium | Remainder |
MECHANICAL PERFORMANCE
| TB SAND CAST | TB GRAVITY DIE CAST | TF SAND CAST | TF GRAVITY DIE CAST | |
|---|---|---|---|---|
| 0.2% Proof Stress (N/mm²) | 120–140 | 140–150 | 220–280 | 250–300 |
| Tensile Strength (N/mm²) | 170 | 230 | 230–290 | 280–320 |
| Elongation (%) | 2 | 3 | 0–1 | 0–2 |
| Impact Resistance Izod (Nm) | 1.4 | 2.7 | 1.0 | 1.4 |
| Brinell Hardness | 80 | 85 | 100 | 110 |
| Modulus of Elasticity (×10³ N/mm²) | 71 | 71 | 71 | 71 |
| Shear Strength (N/mm²) | - | - | 200 | 235 |
BEHAVIOUR AT HIGH TEMPERATURES
LM16 maintains its strength effectively up to around 200°C.
PHYSICAL CHARACTERISTICS
| Coefficient of Thermal Expansion (per °C @ 20–100°C) | 0.000023 |
| Thermal Conductivity (cal/cm²/cm/°C @ 25°C) | 0.34 |
| Electrical Conductivity (% copper standard @ 20°C) | 39 |
| Density (g/cm³) | 2.70 |
| Freezing Range (°C) approx. | 620–550 |
MACHINING QUALITIES
In the heat-treated state, the alloy machines reasonably well, though tools, preferably high-speed steel, must remain sharp. Tool wear can be moderately high, so generous lubrication during cutting is recommended.
RESISTANCE TO CORROSION
LM16 provides sound corrosion resistance when exposed to standard atmospheric environments.
ANODISING SUITABILITY
A protective coating, often greyish in appearance, can be produced using either sulphuric or chromic acid anodising processes.
HEAT TREATMENT
Full heat treatment significantly improves both strength and hardness.
USES AND PRACTICAL NOTES
LM16 is widely used for water-cooled cylinder heads, valve bodies, water jackets, cylinder blocks, fire-hose couplings, air-compressor pistons, fuel-pump housings, aircraft supercharger components, and other applications needing leak-resistant castings combined with the high strength imparted by heat treatment.
It performs well in both sand casting and gravity die casting, and LM16 offers good weldability.