Aluminium Gravity Die Casting Alloy LM9

Aluminium Gravity Die Casting Alloy LM9 Cameo

This alloy conforms to BS:1490 1988 LM9. Castings are standardised in the as cast (M) condition, in the precipitation treated (TE) condition or in the fully heat treated (TF) condition.

Mechanical Properties

M Gravity Die Cast TF Sand Cast TF Gravity Die Cast TE Sand Cast TE Gravity Die Cast
0.2% Proof Stress (N/mm2) 95-120 220-250 270-280 110-130 150-170
Tensile Strength (N/mm2) 190 240 295 170 230
Elongation (%) 3-5 0-1 0-1 1.5 2
Impact Resistance Izod (Nm) - 0.7 1.4 1.4 2
Brinell Hardness 75-85 95 110 70 85
Modulus of Elasticity (103 N/mm2) - 71 71 71 71
Shear Strength (N/mm2) - 200 230 120 160

Physical Properties

Coefficient of Thermal Expansion (per C @ 20-100 C) 0.000022
Thermal conductivity (cal/cm2/cm/ C @ 25 C) 0.36
Electrical conductivity (% copper standard @ 20 C) 39
Density (g/cm3) 2.68
Freezing range (C) approx. 615-550

Strength at elevated temperatures

Tensile properties are unaffected by temperatures up to 150 C but prolonged heating at temperatures significantly higher reduces the strength. For example, the tensile strength of chill cast LM9-TF at 200 C (after heating for 500h) is approximately half that at room temperature, and only 25% of the original value at 250 C.


Very considerable tool wear occurs in machining this aluminium alloy, but there is not the same tendency to drag that occurs with high Silicon alloys containing no other alloying elements, e.g. LM6. Carbide-tipped tools with large rake angles and relatively low cutting speeds give good results. A cutting lubricant and coolant should be employed.

Corrosion Resistance

LM9 exhibits excellent resistance to corrosion under both ordinary atmospheric and marine conditions.


LM9 Can be anodised by any of the common processes, the resulting protective film ranging in colour from grey to dark brown, depending on the method employed.

Heat Treatment

Heat Treatment produces high strength and hardness.

Application and General notes

Having high resistance to corrosion and excellent castability, aluminium LM6 is suitable for most marine 'on deck' castings, water-cooled manifolds and jackets, motor car and road transport fittings, thin section and intricate castings such as motor housings, meter cases and switch boxes, for a very large aluminium casting, e.g. cast doors and panels where ease of casting is essential, for chemical and dye industry castings, e.g. pump parts, and for paint industry and food and domestic castings. It is especially suitable for castings thatare to be welded. The ductility of LM6 enables castings to be rectified easily or even modified in shape, e.g. simple components may be cast straight and later bent to the required contour.

LM6 is equally adaptable for sand casting and aluminium die casting(gravity die casting and pressure die casting). It has excellent resistance to corrosion in marine environments, possesses excellent ductility, but is of medium strength and is not heat treated. Its strength falls off rapidly at high temperatures. Its elastic limit is low and there is difficulty with machining.