When is magnesium worth it?
Magnesium is not worth it everywhere. But for the right parts, few materials can match it. Three application patterns show where magnesium plays to its strengths:
Weight-critical structural parts
At a density of about 1.74 g/cm³, magnesium is around 30% lighter than aluminum and 75% lighter than steel. Its specific strength is higher than both. For parts where every kilogram counts — body structures, seat shells, cross-members — magnesium is the most efficient material.
Vibration and noise requirements
Magnesium damps vibration better than aluminum and steel. This is not a lab value but years of lived practice: steering-wheel armatures are produced in magnesium as standard — partly because vibration reaches the driver's hands less than with an aluminum version. The same property can be used by design for NVH-critical parts, without additional damping measures.
Heat-conduction requirements
The thermal conductivity of magnesium depends strongly on the alloy — the decisive factor is the aluminum content. Low-aluminum magnesium alloys reach values in the range of common aluminum casting alloys; aluminum-bearing die-casting alloys are lower. In all cases, magnesium conducts heat markedly better than steel. For parts that have to dissipate heat — housings, drive components, thermally loaded functional parts — alloy selection is therefore part of the thermal design.
EMC requirements
Magnesium has good EMC properties. That makes the material of interest for housings of electronic components that need shielding against electromagnetic fields.
“Magnesium only pays off at high volumes.” — That is not true.
The claim comes from the die-casting world. There, tooling costs are so high that the material only pays off at series quantities. But die casting is only one of several magnesium processes.
At low quantities, sand casting in magnesium is often the more economical answer — even compared with aluminum die casting. The sand-casting tools are cheaper, the batch size can start at one, and the part quality holds up to series launch.
Which process is right for your part depends on geometry, quantity and part requirement. That is exactly what we clarify in the first conversation — and we tell you whether die casting, sand casting, extrusion or sheet is the most economical solution.
When magnesium is NOT the right choice.
Magnesium is not the right material for every part. For a straight steel substitution with unchanged geometry, it does not work. With direct steel contact and no design separation, the corrosion solution becomes more expensive than the weight saving. In those cases we tell you — before the tool is built, not after.
- When the part is permanently in direct contact with steel and no design separation is possible. Galvanic corrosion is real and solvable by design — but if the solution makes the part more expensive than the weight saving is worth, magnesium is not worth it.
- When the design wants to carry a steel layout over to magnesium one to one. That does not work. Magnesium demands a design of its own — different wall thicknesses, different transitions, different joining technology. If that is not acceptable, the original material is the better choice.
Corrosion and joining technology.
The two issues that decide magnesium projects. Both are technically solvable — but they have to be addressed early, not at series launch.
Corrosion
Magnesium is well resistant to organic and alkaline media. It is sensitive to salt solutions and to galvanic corrosion in direct steel contact.
For corrosion protection, we match the coating to the part requirement. The magnesium-specific conversion coating Oxsilan® from Chemetall — 1,008 hours in salt spray testing with no findings, at automotive level — and cathodic dip coating (e-coat) plus powder coating, we source through established partners. Plain powder coating we carry out in-house.
Joining technology
Magnesium is weldable — but not with every process. We use CMT (Cold Metal Transfer), MIG, TIG, laser, robotic and friction stir welding, depending on part and material. CMT works with particularly low heat input and is therefore suited to thin sheet and dissimilar joints.
One distinctive point: we make our own MnE21 welding wire (1 to 5 mm diameter). This gives us control over the weld metallurgy and makes us independent of supply shortages.
Which parts are possible in magnesium.
Over recent years we have identified, assessed and demonstrated as manufacturable sixteen body and structural parts in magnesium. A selection:
Body
- Hood (inner panel)
- Liftgate (inner panel)
- Door inner panel
- Bulkhead
- Roof cross-member
Structure
- Instrument panel cross-car beam
- Seat shell
- Rear seat back
- Bumper beam
- Front-end carrier
Powertrain and functional parts
- Valve cover
- Cylinder head covers
- Fan wheels
- Engine mount brackets
- Pump and housing parts
- Custom profiles (extrusion)
Part weights between 2 and 22 kg. Quantities from prototype to small series. For higher quantities — die-cast series through our Chinese plant, with no change of contact.
Beyond this list, we have already manufactured a complete magnesium vehicle frame (spaceframe) as a prototype. Details remain confidential — the findings on material behavior and joining technology feed into every magnesium part we make today.
How a magnesium project runs with us.
01
First conversation & feasibility
We assess whether magnesium makes sense in design and economic terms — and say so if another material is a better fit.
02
Design-for-manufacturing review
You send the 3D data. We assess manufacturability and propose geometric adjustments where needed.
03
Tool making & prototype
Tool built in-house, prototype for initial validation testing.
04
Series
Handover to series production at the chosen site, with the suitable joining technology.
One thing we deliberately do not offer: engineering in the sense of design ownership, crash simulation or material release. These remain with you or an engineering partner. We are the manufacturing partner — and we flag it early if your part still needs an engineering loop.
