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Product Bulletin - Solution Heat Treatment
Roller Hearth Furnace
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Roller Hearth Solution Heat Treat Furnace & Age Oven |
The roller hearth furnace line can be employed to heat treat aluminum castings or forgings on a batch/continuous basis. The work is loaded on racks or trays for automatic processing through the entire system.
The furnace is divided into two main zones, one for heating and one for soaking. As racks are charged, they continually move through the unit at a predetermined speed. As the racks approach an internal or external door, a photo-eye signals their location and opens the door. Independently clutched high speed drives then move the racks forward quickly, and stop them automatically at the next position. When the rack reaches the end of the furnace, the rear door is then opened and the rack is quickly moved onto the quench elevator and lowered into the quench tank.
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Roller Hearth Solution Heat Treat Furnace
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Depending upon the alloy that is being heat treated, artificial aging may be required to produce the proper hardness qualities. In castings, hardness can be achieved at ambient conditions if the part remains at rest for a period of time. This is generally not possible as other finishing steps such as machining or painting must be done to maintain production flow at a normal pace. To speed up the hardening process, artificial aging is employed. By raising the temperature of the the work to approximately 350 degrees F, and holding it there for approximately 3-4 hours, hardening will occur. When aging is finished, further processes such as those mentioned can take place.
For extruded alloys, the soaking time is generally minimal. In these cases, the work is heated to temperature and stabilized for a short period of time and quenched. Since extrusions can be in various forms, such as rod, bar, tubing, etc., the furnace many require special considerations that are much different from those mentioned up to this point. Handling of extrusions at solution heat treating temperatures can pose a new set of problems in designing a furnace. One example is shown in figure #3 where the work is placed directly on the rolls. Continuous roll oscillation is used to control distortion of the work. Since the work length approached 52 inches, quenching of these sections is accomplished "on the fly" as they are discharged out of the furnace. The quench enclosure contains a series of spray nozzles positioned above and below the rolls which cools the work as it passes through. The speed at which the work is passing, the volume of water, and the pressure of the spray becomes extremely important.
Determining the exit design depends primarily on the process requirement for the alloy and the work configuration. Whatever the process requirements, SECO/WARWICK has the equipment for your solution heat treating needs.
P. O. Box 908 180 Mercer Street Meadville, PA 16335-6908 USA
Phone (814)332-8400 - Fax (814)724-1407
info@secowarwick.com
©1995-2008 SECO/WARWICK Corporation All Rights Reserved.
The latest design, materials and equipment specifications should be obtained from the company before any reliance is placed on the enclosed since changes may occur due to product improvement.