15-tonne aluminium billet homogenizing furnace

Homogenizing is the heat treatment a cast billet gets before it ever meets the press: soaking at around 580°C removes casting segregation and internal stress, and the controlled cool-down sets the Mg2Si precipitates so the billet extrudes faster without surface tearing. Skip it and the same alloy runs slower, wears dies harder and can show streaks after anodising.

This chamber furnace takes a 15,000 ±500 kg load of 8-inch billets (the design accepts 4–9 inch) at 6–8 m length. Working temperature is 580°C, maximum 610°C, held within ±5°C across the load — four heating zones with four burners and four 15 kW circulation fans (impellers rated to 650°C) keep the air moving evenly through the chamber. A three-dimensional trolley moves the charge, and cooling happens in a separate chamber with a combined air + water system, because in homogenizing the cooling curve matters as much as the soak itself. Firing on natural gas, LPG or diesel (electric version available), with Siemens or Mitsubishi PLC control and temperature logging with data export.

An honest word: this furnace is not for every extrusion plant. If you buy homogenized billets from a smelter, you do not need one. It earns its keep when you cast billets in-house — including from your own process scrap and aluminum dross recovery — or when you buy cheaper unhomogenized stock and upgrade it yourself; the feedstock price difference then pays the furnace back faster than the sticker suggests. Capacities from 5 to 50 tonnes are available — 15 t is a sensible middle for a casthouse feeding one or two presses.