Gravity die casting — also known as permanent mould casting — uses a reusable steel mould into which molten aluminium is poured under gravity. Unlike sand casting, the permanent mould produces a consistent, fine-grained surface finish and tighter dimensional repeatability across production runs. Unlike high-pressure die casting, it is well suited to thicker-walled, pressure-bearing components where porosity-free internal soundness is critical.
For aluminium parts that require PED compliance, pressure tightness or structural integrity, gravity die casting offers the best balance of dimensional accuracy, mechanical properties and cost at low-to-medium volumes. Parts are typically heat-treated after casting to achieve the required temper — T5 or T6 for most structural and pressure applications.
Gravity die casting is the right process for pressure-bearing, thicker-walled aluminium components requiring PED 2014/68/EU compliance, good mechanical properties after heat treatment, and medium production volumes. Minimum wall thickness is typically 3–4 mm.
For high-volume, thin-wall, non-pressure aluminium components (housings, brackets, heat sinks, enclosures), aluminium high pressure die casting → is the appropriate process. HPDC is not used for PED-certified pressure-bearing parts.
We routinely cast the principal EN 1706 gravity die alloys and their international equivalents, including:
Other alloys and bespoke chemistries can be sourced to your specification. Full chemical and mechanical certification is supplied with every batch, issued against EN 1706, ASTM B26 or equivalent as required.
| Single-piece weight | From 2 kg up to 20 kg within PED approval scope |
| Linear tolerance (as-cast) | Typically CT6–CT7 (ISO 8062) on gravity die features |
| Surface finish | Ra 6.3 µm or better on most as-cast surfaces |
| Wall thickness | Up to 30 mm within PED approval scope; 3 mm minimum typical |
| Diameter | Up to 350 mm within PED approval scope |
| Heat treatment | T5, T6 or T7 tempers available; solution treatment and ageing in-house |
| Machined features | Held to drawing tolerance via CNC milling, turning and drilling |
Aluminium alloy castings used in pressure equipment — pump housings, valve bodies, compressor components, fluid manifolds — must comply with the Pressure Equipment Directive 2014/68/EU where the equipment falls within its scope. Our partner foundries hold PED certification for aluminium gravity die castings, and we can supply the documentation required to satisfy your CE marking obligations. PED explained →
PED compliance for aluminium castings typically requires:
We manage the full documentation package and ship certified parts on a DDP basis. You receive the casting and its paperwork together — ready for your own inspection and CE marking records.
Every pressure-bearing aluminium casting is produced and inspected to a defined quality plan. Standard capabilities include:
Our aluminium alloy castings are used across demanding industrial sectors:
Send us a drawing, target volume and alloy specification and we will return a budgetary quotation within three working days.
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