Overhauling a low-pressure die casting furnace: when the general overhaul is the better investment

A second life for industrial plant is more than a repair. This low-pressure die casting furnace went through a complete reconditioning process — from collection at the customer's site to the return of a comprehensively overhauled unit. The aim is not a cosmetic refresh, but restored reliability and a lastingly extended lifespan.

How a low-pressure die casting furnace works

Unlike a melting or holding furnace, a low-pressure die casting furnace (LPDC) is a closed pressure vessel. A slight gas overpressure of around 0.2 to 0.7 bar is built up above the aluminium bath. This pressure forces the melt upwards from below in a controlled manner through a riser tube and into the die — with few bubbles and precisely metered. It is exactly this design that places particular demands on the refractory lining: it has to withstand the aluminium and at the same time form part of a leak-tight pressure system.

How our fitters go about it

What matters during the overhaul

• Bath lining: non-wetting, corundum-resistant materials prevent liquid aluminium from infiltrating and corundum from closing up the cross-section — the basis for service life and melt cleanliness.
• Riser tube and tube seat: the riser tube is the most heavily loaded component. The seat and connection have to be dimensionally accurate and tight so that metering remains reproducible.
• Pressure tightness: as a pressure vessel, the furnace has to remain gas-tight at the lid, the penetrations and the sealing faces — one leak costs metering accuracy and process reliability.
• Dimensional accuracy: the geometry of the bath, riser tube and lid directly determines casting quality. Millimetres count here.
• Controlled first heat-up: after relining, bound water only escapes safely from the structure along a defined heat-up curve with holding stages.

General overhaul instead of buying new

A fully reconditioned furnace achieves the reliability of a new unit — at a fraction of the investment and with a considerably shorter procurement time. Final assembly and commissioning at the customer's site are no longer part of refractory construction, but of the final installation of the plant.

The overhauled unit