Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Magnesium alloy casting is a manufacturing process in which molten magnesium alloys are poured or injected into a mold to produce complex-shaped metal parts. Magnesium alloys are among the lightest structural metals (density ≈ 1.74–1.85 g/cm³, about 2/3 that of aluminum and 1/4 that of steel), making them very attractive for weight-critical applications.

Key Characteristics of Magnesium Alloys for Casting

1.Excellent strength-to-weight ratio

2.Good damping capacity (vibration absorption)

3.High thermal and electrical conductivity

4.Excellent machinability and surface finish

5.Good castability (low melting point ~650 °C, good fluidity)

Common Magnesium Casting Alloys

1.AZ91D (Mg–9Al–1Zn): Most widely used, excellent castability and corrosion resistance with protective coating

2.AM60B / AM50A (Mg–6Al or 5Al–Mn): Better ductility and energy absorption, used in automotive safety parts

3.AE44 (Mg–4Al–4RE rare earth): Superior creep resistance at high temperature

4.WE43, Elektron 21, etc.: High-performance alloys for aerospace and elevated-temperature applications

Main Casting Processes for Magnesium Alloys

1.Die Casting (most common, ~90% of magnesium structural parts)

A.High-pressure die casting (HPDC): Cold-chamber process (molten Mg injected at high speed into steel dies)

B.Advantages: High production rate, excellent dimensional accuracy, thin walls (down to 1 mm), good surface finish

C.Typical parts: Automotive (instrument panels, steering wheel cores, seat frames, transmission cases), electronics housings (laptops, cameras), power tool housings

2.Sand Casting

A.Used for low-volume, large, or complex prototype parts

B.Green sand or resin-bonded sand molds, often with inhibitors to C.prevent magnesium reaction with moisture

D.Larger wall thickness required, rougher surface

3.Permanent Mold / Gravity Casting

A.Metal molds, lower production rate than die casting

B.Better mechanical properties than HPDC due to slower cooling

4.Investment Casting (rarely used)

For very complex, thin-walled aerospace parts

5.Squeeze Casting and Semi-Solid Processes (Thixomolding, Rheocasting)

Combine advantages of casting and forging → higher strength and ductility, minimal porosity

Special Considerations for Magnesium Casting

A.Fire hazard: Molten magnesium reacts violently with oxygen and water → protective gas cover (SF₆, SO₂, or newer fluorine-free alternatives like Novec 612 or HFC-134a) and strict safety protocols required.

B.Corrosion: Pure magnesium corrodes easily; alloys need protective coatings (chromate, anodizing, e-coating, powder coating) or design that avoids galvanic couples.

C.Porosity: High-pressure die castings can have gas porosity; newer vacuum die casting or squeeze casting greatly reduces it.

Major Applications Today

A.Automotive: Crankcases, gearbox housings, steering column parts, wheels (some high-end)

B.Aerospace: Gearboxes, helicopter transmission housings, satellite components

C.Consumer electronics: Laptop and phone bodies (historically Apple, now less common due to cost)

D.Medical: Lightweight orthopedic implants, camera arms

E.Power tools and sporting goods

In short, magnesium alloy casting (especially high-pressure die casting) is the go-to process when engineers need the lightest possible structural metal component with good strength and excellent manufacturability, provided the part will be properly protected against corrosion.