Aluminum Solution Heat Treat Furnaces

Aluminum Solution Heat Treatment

The purpose of aluminum solution treatment is to enhance the mechanical properties of aluminum alloys by optimizing their microstructure through a heat treatment process. The aluminum alloy is heated to a sufficiently high temperature to dissolve the alloying elements (such as copper, magnesium or silicon) evenly into the aluminum matrix. It is then quenched in water, glycol or air, which traps the alloying elements in a supersaturated, very homogenous solid state. The aluminum alloy is then aged (precipitation hardened) at a lower temperature, which significantly enhances its mechanical properties, particularly its strength and hardness.

Aluminum Heat Treatment Furnaces

Wisconsin Oven designs aluminum solution treat furnaces for a wide variety of load sizes and weights, with quench delay times from 5 to 20 seconds. Our furnaces are used for solution heat treatment of aluminum extrusions, sheet metal, and castings, and include drop bottom furnaces, horizontal quench furnaces (which provide a reduced footprint and lower price), and continuous designs.  

Solution Treating FAQs

What is aluminum solution treatment?

Aluminum solution treatment is a process for improving the strength of aluminum alloys. It includes three steps: (1) Heating to the solution temperature (just below melting temperature), (2) quenching in water, glycol, or air, and (3) aging at a lower temperature for a specified period of time. Solution treatment is necessary to give aluminum the required strength, hardness and toughness to make it suitable for structural and other load bearing applications that experience mechanical stress or are susceptible to fatigue. 

What aluminum alloys can be solution treated?

The following aluminum alloys are heat treatable, and each has its own niche application(s): 2000 series (which contains copper), 6000 series (which contains magnesium and silicon), and 7000 series (which contains zinc). These specific aluminum series’ can be solution treated because the alloys they contain can be dissolved into the aluminum at elevated temperature.

What quench delay is required for aluminum solution treatment?

Quench delay is a limit placed on the amount of time between when the door of the solution treat furnace starts to open, and when the aluminum load is fully submerged in the (water or glycol) quenchant. This delay must be minimized to prevent the aluminum from cooling down too much prior to quenching. The allowable quench delay is dependent on the thickness of the aluminum, and ranges from 5 to 7 seconds for thin aluminum sheets or tubes, up to 12 or 15 seconds or more for thick aluminum castings. 

What temperature is required for solution treatment of aluminum?

Prior to quenching, the aluminum is heated to 800 to 1,100°F (426 to 593°C), depending on the alloy, in an solution treat furnace. The temperature uniformity, which refers to the +/- tolerance of the temperature in the solution treat furnace, is critical to ensuring successful results. Solution treatment typically requires a tolerance of +/- 10°F (+/- 6°C) or sometimes +/-5°F (+/-3°C) for certain application. This is expressed, for example, as 900°F +/-10°F, which means that the temperature within the heating chamber interior must not be less than 890°F nor greater than 910°F. This tolerance must be tested and guaranteed by the furnace manufacturer. 

Are solution treat systems available that are equipped with Industrial Internet of Things (Iot)?

An Industrial IoT system monitors the solution treat equipment using a multitude of sensors and sends the information to the furnace manufacture in real time. This permits quick, remote diagnosis of any problems that arise, avoiding extended downtime, and allows for planned maintenance. Some manufacturers include this technology with their furnaces. 

What features make a good solution treat furnace?

A few important things to consider when purchasing of a solution treat system are:

  • Temperature uniformity validation: The furnace manufacturer should guarantee the temperature uniformity tolerance (+/- 10°F or +/- 6°C, for example) and validate it with testing prior to shipment.
  • Stainless steel lined interior: It is best if the furnace interior is lined with stainless steel sheet metal, as opposed to exposed insulation. This is especially true for drop bottom furnaces, where steam from the quench process will rise out of the tank during each quench cycle and condense into the exposed insulation, eventually requiring rebuilding of the furnace interior.
  • Maintenance free door seals: Look for solution treat furnaces with maintenance-free seals on the doors, in lieu of tadpole gaskets that require periodic replacement. 
  • Assembly and testing prior to shipment: Try to find a manufacturer that will fully assemble and test the solution treat system before shipment. Established furnace manufacturers should have large enough facilities to be able to accomplish this.
  • Field service: Most reputable manufacturers offer installation supervision or full turnkey installation with their equipment, and it is important this is included with the purchase to ensure a timely and trouble-free installation and startup.  
  • Industrial IoT (Internet of Things) technology: Some furnace manufacturers include an industrial IoT system that remotely monitors the equipment and sends the data to the furnace manufacture in real time. This permits timely, remote analysis of any problems that arise, rather than waiting days or weeks for a service technician to visit.  

What is the difference between a drop bottom furnace and a horizontal quench furnace?

Drop bottom furnaces and horizontal quench furnaces are both used for solution treatment of aluminum. The drop bottom is elevated above the quench tank, and has the door on the bottom. The quench operation is performed by quickly lowering the aluminum load into the quench tank. The horizontal quench is located at ground level, and has the door on the front. The quench operation is performed by quickly moving the load out of the furnace onto a quench elevator located above the quench tank, which quickly lowers it into the tank. Generally speaking, horizontal quench systems are less costly and more compact than drop bottom systems, but are limited in the size and quench delay that can be achieved. 

Floor space comparison

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