LM25 Aluminum Alloy Ingot

About LM25 Aluminum Alloy Ingot

LM25 under BS 1490 is defined precisely in terms of chemical composition, mechanical properties, heattreatment conditions, and physical characteristics. The standard positions LM25 as an AlSi7Mg casting alloy with controlled impurities and strong heattreat response.

Chemical Composition (BS 1490 LM25)

The following limits come directly from BS 1490 specifications for LM25.
Values are in weight %.

*Minimum 0.05% Ti if used alone for grain refinement.

Mechanical Properties (BS 1490 LM25)

Mechanical properties depend strongly on casting method and heat treatment.

Sand Cast As Cast (LM25M)

• Tensile Strength: 130 MPa min
• 0.2% Proof Stress: 80100 MPa
• Elongation: 2%
• Hardness: ~5565 HB

HeatTreated Conditions

BS 1490 defines several conditions:

• LM25TE (precipitation treated)
• LM25TB7 (solution treated + stabilized)
• LM25TF (fully heattreated, equivalent to T6)

Typical values from BS 1490 data:

Physical Properties (BS 1490 LM25)

• Density: 2.68 g/cm
• Freezing Range: 615550C
• Thermal Conductivity: ~0.36 cal/cm/cm/C/s
• Electrical Conductivity: ~39% IACS
• Coefficient of Thermal Expansion: 22 10 /C (20100C)

Casting Characteristics (BS 1490)

• Good fluidity suitable for thinsection castings.
• Moderate hottearing tendency requires controlled gating and feeding.
• Machinability: moderate; tools must be sharp.
• Corrosion resistance: excellent, especially in marine environments.
• Anodising: protective films possible; decorative colouring limited due to grey oxide.

Summary Table (BS 1490 LM25)

If you want, I can also prepare a LM25 vs A356 vs LM6 comparison specifically for casting performance and heattreat response, which is often useful for alloy selection in engineering applications.