FEATURE ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2023 42 Integral quenching (IQ) is a widely adopted heat treatment technique known for its efficient and rapid quenching capabilities. While applying vacuum pro- cessing in IQ is not a new concept, it has been limited in batch size capacity in vertical orientations. To address this limitation, a vertical vacuum IQ furnace has been developed. The principal reason for the vertical vacuum is to expand work zone size while leveraging the benefits of both vertical and vacuum treatment. Additionally, with current technology, there is the opportunity to expand on automation capabilities. In this article, the vertical vacuum IQ furnace line (Fig. 1) is introduced; it comprises a loading station, a vacuum furnace, a water wash tank, and tempering furnaces–all interconnected via a loading system. The operational workflow of the vertical vacuum furnace and integration of supervisory control and data acquisition (SCADA) systems allow for autonomous INTEGRATION OF VACUUM PROCESSING INTO AN AUTOMATED VERTICAL QUENCHING FURNACE Vertical vacuum integral-quenching furnaces give heat treaters a larger working zone for efficient and rapid quenching. Zoe J. Rex* and Bob Acken Rex Heat Treat, Lansdale, Pennsylvania Fig. 1 — The vertical vacuum IQ furnace line. 6 *Member of ASM International processing and are also discussed. The findings presented provide insights into the advancements and potential applications of vertical vacuum IQ furnaces in the heat treatment industry. VERTICAL VACUUM IQ FURNACE LINE OVERVIEW The vertical vacuum IQ furnace line is a novel configuration designed to overcome the limitations of traditional IQ vacuum furnaces. The line includes a loading station, a vacuum furnace, a water wash tank for post-oil quench treatment, tempering furnaces, and an automated loading system known as the loader. The loading station serves as the initial point where hardware is staged prior to the heat treatment process. The loading system, or loader, is directed by the SCADA to automate transitions between furnaces and complementary equipment on the furnace line. Transitions such as a quench-to-water wash and subsequent transfer-to-temper cycle, and many more variations are directed by the SCADA and can be performed autonomously. The vacuum furnace consists of a hot chamber and a cold chamber with an inner door separating the two, the former containing the work zone and the latter housing the gas quench chamber and an oil quench tank directly below. Due to the multi-chamber nature of the vertical vacuum furnace, the inner door separating the hot and cold chambers prevents incorporating load thermocouples for temperature monitoring during production. A workaround to this limitation is to use a temperature- resistant recorder that can be loaded into the furnace with the hardware. The load thermocouples can then be connected to the recorder such that thermal data may be transmitted wirelessly or downloaded post processing. OPERATIONAL WORKFLOW Hardware is manually placed onto the loading station. The recipe is started, and the SCADA directs the
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