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When the cast part needs more strength.

Heat treatment

Gravity cast aluminium parts are heat treated here to raise tensile and ultimate strength. Pressure die cast parts normally cannot be heat treated.

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Post-processing · aluminium

Heat treatment

A gravity die cast bracket that is heat treated after casting gains higher tensile and ultimate strength. That can decide whether the part can be cast at all, or has to be made another way.

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The principle

Why not every part can be heat treated

This is a relationship worth knowing before you design a cast part that has to take a lot.

A die cast part contains trapped gas. The metal is injected so fast that air is entrained and stays in the section. That is rarely a problem in service, but heat the part in a furnace and the gas expands and lifts the surface into blisters. Die cast parts are therefore normally not heat treated.

A gravity die cast part fills calmly under gravity. Less air is entrained, and the part can be heat treated.

The consequence for you as a designer: if the part needs heat treated strength, the process is decided before you have finished drawing. It is gravity die casting, and the part should be dimensioned for it from the start, with heavier sections and draft angles that suit the process.

An example from our portfolio: a gravity die cast bracket that is heat treated.

Suitability

When heat treatment is right — and when it only costs

Heat treatment is a separate process step with its own cost, its own lead time and its own scrap risk. Specify it where it does a job, not by default.

Heat treat when

  • The part is load-bearing and the strength requirement sits above what as-cast metal gives.
  • The part has to take fatigue — alternating load over time, not a single load case.
  • The drawing calls for a heat treated temper. Which tempers we run is available on request.
  • The alternative would otherwise be a heavier part in thicker section to reach the same strength.

Skip it when

  • The part is pressure die cast. Trapped gas expands in the furnace and raises blisters under the surface.
  • The part is in zinc. Zinc alloys are not heat treated.
  • The part is not load-bearing. A cover or a fitting that just holds something in place rarely needs it.
  • Tolerances are very tight and the faces will not be machined. Heat treatment can move the part.

Data sheet

Specifications — heat treatment

The effect is documented in our portfolio. The cycle itself, meaning temper, temperature and soak time, is not published yet.

Machine park

Processes in house
Pressure die casting (aluminium and zinc), gravity die casting, CNC turning, CNC milling, boring, heat treatment, blasting
Processes we do not have
Sand casting, toolmaking, anodising, powder coating
CAM software
Autodesk Fusion 360
Number of die casting machines
Available on request
Clamping force
Available on request
Hot or cold chamber
Available on request
Maximum shot weight
Available on request
Platen size and maximum die height
Available on request
Gravity casting stations
Available on request
Maximum mould size, gravity
Available on request
Melting furnaces and melting capacity
Available on request
CNC lathes
Available on request
Maximum turning diameter and length
Available on request
CNC mills
Available on request
Milling work envelope
Available on request
Boring machine
Available on request
Heat treatment furnace
Available on request
Blasting equipment
Available on request
Automation
Available on request
Machining operations
CNC turning, CNC milling, boring, tapping, sawing, grinding
Machining experience
More than 30 years
Number of axes, milling
Available on request
Heat treatment applies to
Gravity die cast aluminium parts
Heat treatment — effect
Higher tensile strength and higher ultimate strength
Tempers we run
Available on request
Blasting
In house
Anodising
Via subcontractor — aluminium only, zinc cannot be anodised
Powder coating
Via subcontractor
Finishing subcontractors
Available on request
Die ownership
The customer owns the tool. We procure it, specify it for our machines and maintain it.
Typical tooling cost
Available on request
Die life, aluminium
Available on request
Die life, zinc
Available on request
Storage and insurance of customer-owned dies
Available on request
Shift pattern
Available on request

Alloys

Metals
Aluminium and zinc
Feedstock form
Ingot from established suppliers
Aluminium supplier
Metallco, Toten, Norway — secondary aluminium realloyed against international standards
Aluminium melting point
660 °C
Aluminium casting temperature
680–700 °C
Alloy selection
Made together with the customer, as part of the design review
Aluminium alloys, pressure die casting
Available on request
Aluminium alloys, gravity
Available on request
Zinc alloys
Available on request
Customer-specified alloy
Available on request
Material certificate
Available on request
Melt and batch traceability
Available on request
Recycled content
Available on request

Questions and answers

Heat treatment — common questions

That depends on the alloy and the temper, not on us. For the classic heat-treatable gravity alloy EN AC-42100 (AlSi7Mg0.3), EN 1706 states a minimum tensile strength of 170 MPa as cast and at least 290 MPa in the T6 condition — and the yield strength more than doubles, from 90 to 210 MPa. Those are standard values from the alloy standard, not measurements on our parts.

Available on request.

It can. Solution treatment happens close to the melting range of the alloy, and thin or asymmetric sections can pull. If a part is both heat treated and has tight tolerances, we normally put the machining after the heat treatment — not before.

Unsure whether your part meets its strength requirement?

State the requirement in your enquiry and we will tell you which combination of process, alloy and heat treatment meets it.

Send an enquiry

Related capabilities

Zinc die casting

Thin walls, sharp detail and long die life. Very few Norwegian suppliers offer it.

Aluminium casting

Die casting or gravity die casting? We help you choose, and cast the part in Råde.

Aluminium die casting

Thin walls, complex geometry and seconds per shot, in recycled aluminium.

Want us to look at your part?

Send the drawing and the quantities you have in mind. We look at wall thickness, draft angles, radii and parting line before we work out a price.

Send a drawing

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