FEATURE ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2025 43 the ingress of ambient air into the furnace. Switching back to pure H2 atmosphere for production requires less time from a N2/H2 atmosphere than from a pure N2 atmosphere. When investigating the hot zone temperature (blue solid line in Fig. 4) in a whole week (from Thursday to the following Wednesday), it was found that the furnace temperature was set at a high level during the weekend. Normally, it should be set to the standby temperature. But, for this particular weekend, the furnace temperature was set 400°F higher. In Fig. 4, the “H2% in Furnace” (orange dotted line) was around 30% during that weekend, which shows that the furnace was not in the production mode during the weekend. (If the furnace was under the normal production mode, “H2% in Furnace” reading should be at 100%.) So, there was an incident of “waste of energy” to keep the unexpected hotter furnace over the weekend. After such events happened and were detected by the smart process monitoring system several times, it was decided to implement an algorithm to send a text message to the furnace operator, “Furnace temperature is not lowered for weekend,” to remind them to avoid such incidents. Another benefit that is an outcome of this process monitoring system is the reporting function. As mentioned before, all the data are collected and sent to a cloud server to store. Emailed custom reports can be produced and sent to a designated group of people daily, weekly, monthly, or for a preset period. A typical report includes furnace operation and products information details such as process details with warnings/alerts, utility usage, operation period under different temperatures, diagram to show the atmosphere flow vs. furnace temperature, KH (H2/H2O) of atmosphere for different products, and product quality information. In addition to this emailed report, any technical or process documents that are needed for production, including process certification, can be designed and produced automatically if the data are available on a cloud server. This will significantly improve job efficiency and reduce the cost to manually prepare the documentation. CONCLUSIONS The smart heat-treating atmosphere and process advisor system delivers significant benefits for heat treatment processes: • Regulation of Atmosphere Gases: Thermodynamic modeling and active measurements enable precise control of furnace atmospheres. • Real-time Production Overview: Operators have immediate access to key process parameters and can respond quickly to deviations. • Alarming Functions: Automated alerts improve awareness of abnormal conditions and support rapid troubleshooting. • Automated Reporting: Customizable reports enhance production tracking, certification, and efficiency. By integrating 4.0 technologies, the system supports data-driven optimization, improves product quality, reduces costs, and enhances operational reliability. The adoption of smart solutions in heat treatment is accelerating, driven by the need for connectedness, real-time insights, and resilience in manufacturing. ~HTPro For more information: Liang He, application engineer, Air Products and Chemicals Inc., 1940 Air Products Boulevard, Allentown, PA 18104, 610.481.8181, HEL5@airproducts.com. Selected References 1. G. Reinhart, Handbuch Industrie 4.0, p. 160, 25, 2017. 2. G. Plicht, D. Millington, and L. He, Innovative Atmosphere Control System for Annealing Furnaces, Air Products and Chemicals Inc., 2019. 3. University of Cambridge, www.doitpoms.ac.uk/tlplib/ ellingham_diagrams/ellingham.php. 4. G. Schuh, et al., Industrie 4.0 Maturity Index, Managing the Digital Transformation of Companies. Herbert UTZ Verlag, p. 16, 2017. 5. McKinsey, www.mckinsey.com/business-functions/ operations/our-insights/covid-19-an-inflection-point-forindustry-40, 2021. 6. Epicor, www.epicor.com/en-us/resource-center/articles/ what-is-industry-4-0, 2021. 7. Air Products, Atmosphere Solutions for Metals Processing, www.airproducts.com/industries/metals-and- materials-processing, 2021. Fig. 4 — Furnace temperature and H2% in furnace in a week. 9
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