Heat treatment lines

Casting
Batch or continuous homogenizing

If you want standard AA6xxx series alloys, continuous homogenizing is your first choice. Most of these billets are homogenized in one of the 120 continuous furnaces manufactured by Hertwich and installed around the world.

We configure all our homogenizing plants to meet all your wants and needs relating to throughput, floor area, and technical features. However, batch-type homogenizing is still the best technology for some applications: alloys which require long holding times of 6 - 12 hours, large-only log diameters, frequent temperature changes, or intermittent production. That explains why, in recent years, Hertwich has supplied several batch homogenizing plants featuring state-of-the-art technology. As a result, they achieve outstanding metallurgical quality and productivity.

Concepts

Batch homogenizing

Let’s take a look at homogenization in a conventional batch furnace. Here, the temperature cycle of a log largely depends on its position in the batch. It follows that logs at the edges of a batch are more exposed to the convection from the heated gases. That means they reach the set temperature ahead of logs in the center. Now, our new generation of batch furnaces with reversing air function achieve 20 % faster heating. Due to the reversing airflow, there is only a slight temperature deviation between the outer and inner logs.

Continuous homogenizing

The diagram below shows the temperature cycle in a continuous homogenizing plant. Logs travel through the furnace and the cooling station on one level. First up, the furnace comprises a heating and a holding compartment. The heating compartment ensures the logs reach a uniform specified temperature. Installed at the end of the heating compartment, sting thermocouples verify the temperature of each log. Next, the logs travel to the holding compartment. Here they are kept to precisely the set temperature throughout the holding time. This period can be from 2 to 9 hours. Finally, the cooling station cools the logs according to the selected regime. Simply adjusting the fan speed controls the cooling rate in the air cooler. All this ensures the heating, holding, and cooling parameters are exactly the same for every log.

Technology

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Continuous homogenizing

This fully automated production sequence starts when the cast logs arrive on the log laydown table. Next, they travel over an accumulator to the inspection station, where they are inspected visually for surface defects and tested ultrasonically (UT) for internal cracks and inclusions.

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Batch homogenizing for round logs

Many major aluminum producers combine continuous and batch homogenizing systems for ultimate flexibility. 

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Batch homogenizing for rolling slabs

Our fully automated homogenizing plants with integrated slab storage are ideal for rolling slabs from AA 2xxx to AA 7xxx series alloys. These are hard AlCu/AlZn alloys mainly destined for the aircraft industry. 

Contact

SMSgroup Deubler, Elke

Elke Deubler

Hertwich Engineering GmbH
Weinbergerstraße 6
5280 Braunau am Inn
Austria

Phone : +43 7722 806 112
Fax : +43 7722 806 122

SMSgroup Wimroither, Günther

Günther Wimroither

Hertwich Engineering GmbH
Weinbergerstrasse 6
5280 Braunau am Inn
Austria

Phone : +43 7722 806 -112
Fax : +43 7722 806 -122

SMSgroup Oberweger, Thomas

Thomas Oberweger

Hertwich Engineering GmbH
Weinbergerstraße 6
5280 Braunau am Inn
Austria

Phone : +43 7722 806 112
Fax : +43 7722 806 122