The LM24 aluminum alloy is a top material in the high-pressure die casting industry, highly favored for its exceptional balance of good castability and robust mechanical strength. It has been classified under the British Standard (BS 1490:1988), LM24 is a Copper-Silicon-Aluminum alloy that serves as the near-equivalent to the widely used US alloy A380.
It offers manufacturers a reliable, cost-effective solution for producing complex, pressure-tight components where moderate corrosion resistance is acceptable. Its fluidity allows it to fill the molds easily, making it a workhorse for demanding automotive and general engineering applications.
The Identity of LM24
LM24 is defined by its specific elemental makeup, where Silicon provides fluidity and Copper contributes significantly to its strength.
A. Chemical Composition (BS 1490:1988 LM24)
The controlled inclusion of Silicon, Copper, and Iron gives the alloy’s performance in the casting process.
| Element | Weight Percentage (%) |
| Silicon (Si) | 7.5 – 9.5 |
| Copper (Cu) | 3.0 – 4.0 |
| Iron (Fe) | 1.3 max |
| Zinc (Zn) | 3.0 max |
| Magnesium (Mg) | 0.3 max |
| Manganese (Mn) | 0.5 max |
| Nickel (Ni) | 0.5 max |
| Aluminium (Al) | Remainder |
B. Physical Properties of LM24
These properties are crucial for optimizing die design and casting parameters, particularly regarding heat transfer and solidification.
| Property | Value | Unit |
| Density | 2.79 | g/cm3 |
| Melting Range (approx.) | 520 – 580 | ∘C |
| Thermal Conductivity (@ 25C) | 0.23 | cal/cm2/cm/∘C |
| Coefficient of Thermal Expansion | 21×10^6 | per ∘C |
LM24’s Performance Profile
The high strength is the key advantage of LM24 over high-silicon, corrosion-resistant alloys like LM6. Note the significant difference between properties achieved via high-pressure die casting versus gravity casting.
Mechanical Properties of LM24 (As-Cast)
| Property | Pressure Die Cast | Gravity Die Cast | Unit |
| Tensile Strength | 320 | 180 | N/mm2 |
| 0.2% Proof Stress | 150 | 100 – 120 | N/mm2 |
| Elongation | 1 – 3 | 1.5 | % |
| Brinell Hardness | 85 | 85 | HB |
Applications & Why LM24 Excels
The core strength of LM24 is its utility in Pressure Die Casting, producing components for structural and fluid-handling applications.
- Automotive Parts: LM24 is highly prevalent in the automotive industry for manufacturing engine components, gearbox casings, clutch housings, and brackets where good mechanical properties are required at ambient and moderately elevated temperatures (retaining strength up to approximately 150∘C).
- Engineering Components: The alloy’s pressure-tightness makes it ideal for hydraulic and pneumatic parts, such as pump housings, valve bodies, and general machine tool components.
- Castability: Its excellent LM24 casting characteristics ensure fine detail reproduction and consistent quality, crucial for mass-produced parts.
Manufacturing and Handling
- Casting Method: LM24 is essentially a pressure die casting alloy. Its superior fluidity allows for the casting of components with thin walls and complex internal features.
- Machinability: Machining practice is generally good, though the Silicon content necessitates the use of carbide-tipped tools for prolonged tool life and a quality finish.
- Welding and Heat Treatment: LM24 is generally considered to have poor weldability and is rarely subjected to the standard T6 heat treatment, as its mechanical properties are typically sufficient in the as-cast condition.
Conclusion: A Versatile Alloy for Demanding Applications
The LM24 aluminum alloy remains a cornerstone in the die casting industry. Its advantageous combination of superb fluidity for intricate castings and high mechanical strength makes it a reliable and cost-effective solution for structural components across the automotive and general engineering sectors. While other alloys may offer better corrosion resistance or slightly different performance profiles, the balanced characteristics of LM24 ensure its continued relevance as a premier choice for high-volume, pressure-tight applications.
Partner with Texa Metals for Your LM24 Casting Needs
As a leading manufacturer and supplier, Texa Metals is a proud producer of high-quality LM24 aluminum alloy ingots. We adhere to stringent international standards, ensuring consistent chemical composition and metallurgical integrity.
If your project demands the excellent castability and mechanical performance of LM24 for critical components like engine mounts, pump bodies, or transmission housings, trust Texa Metals to deliver the precise material you need.
Contact our sales team today to discuss bulk supply, custom specifications, or to request a quote for LM24 alloy.
