The Mercalloy series offers an attractive solution for higher performance structural diecastings.
Mercally HF (high fatigue strength, AA 362) is a eutectic (11% Si) alloy for most intricate, thin-walled parts, with high requirements on mechanical properties.
Castability: Due to a silicon content of about 11%, the fluidity of the 362 is excellent and parts with thin walls and numerous ribs can be cast without problems at the lowest possible temperature. Alloy 362 freezes at a single temperature like a pure metal, has a lower shrinkage contraction and a lower density than any of the hypoeutectic Al-Si alloys due to its higher silicon content. Because of the absence of the iron phase beta-needles, the 362 (like all Mercalloy alloys) have excellent fluidity and resistance to hot cracking, which makes it possible to produce castings that are large in size and intricate in shape.
Crash behaviour: The big advantage in crash relevant applications that any Mercalloy has over other structural diecasting alloys is its low manganese content of 0.25-0.35% which accounts for its greater ability to absorb energy on impact at high strain rates (due to reduced intermetallics Mn-compound, Al12Mn3Si2 ). This low manganese range also increases its tolerance of a higher iron level of 0.25% max Fe (compared to similar alloys) in avoiding the precipitation of the intermetallics Mn-compound.
Finishing: Polished finishes of the 362 alloy are good. Anodized coatings are good because of the small size of the die cast eutectic silicon. Very good finishes are achieved with electroplated and chemical conversion coatings.
Corrosion Resistance: Cast parts in Mercalloy 362 can be used without corrosion protection. This alloy has excellent resistance to corrosion and stress corrosion cracking [higher than 360 and A360] because of the low copper content.
Machinability: MercAlloy 362 has good machinability when wear resistant tools with liberal rakes and clearance angles are used at moderate to fast speeds.
Weldability: Excellent welds are obtained by common methods, if entrapped air from die casting is not a problem. Brazing is not recommended.
Mercury Marine uses Alloy 362 for all marine high-pressure die casting engine blocks, gear cases, and similar key engine components. Excellent fatigue strength of this material has enabled further marine engine weight reduction through optimization of geometry.
Examples of suitable automotive applications include engine blocks, oil pans, housings, covers and any other engine, suspension, or chassis component that requires high-fatigue strength and corrosion resistance.