FEATURE ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2025 41 TABLE 1 — RELEVANT FURNACE ATMOSPHERE DATA FOR AN ADVANCED ADVISOR SYSTEM Requirements for Measure Device Reason N2/H2 atmospheres Atmosphere temperature Thermocouple • Calculate oxidizing or carbon potential • Identify issues with heating or temperature profile O2 atmosphere Oxygen probe or sensor • Calculate dew point with H 2 or oxidizing potential • Monitor oxidizing potential and control furnace • Atmosphere against a set-point H2 atmosphere Thermal conductivity analyzer • Calculate oxidizing potential and dew point • Control dew point against a set-point to avoid decarburization H2 supplied blend Thermal conductivity analyzer • Identify furnace or supply issues N2/H2/CO atmospheres CO atmosphere Infrared analyzer • Calculate carbon potential • Monitor and control carbon potential against a set-point Alternative or helpful operating parameter CO2 atmosphere Infrared analyzer • Calculate carbon potential (backup to O 2 probe) DP atmosphere Dew point analyzer or zirconia-oxide probe • Calculate oxidizing potential Furnace pressure Pressure indicator • Monitor furnace tightness Atmosphere flow to furnace Flow meter • Monitor sufficient atmosphere flow to avoid air ingress Atmosphere supply pressure Pressure indicator • Identify gas supply issues Charge weight Weight or manual input • Impact of charge weight on atmosphere compositions and part quality Charge surface Manual input • Impact of part surface area on atmosphere compositions and part quality Part speed of annealing time Motor or timer • Impact of heat treatment time on atmosphere compositions and part quality 7 • Cloud Server: Tracks all available data, runs customerspecific algorithms, and stores information for analysis and reporting. • Data Logger and Communication Panel: Collects data from the atmosphere control system and other furnace sensors, transmitting it to the cloud via analog, digital, or wireless connections. Local data logging ensures continued operation during network interruptions. Users can access the cloud server to view current atmosphere and process conditions, select key measurements, and download data for further analysis. CASE STUDY: OPTIMIZATION OF ANNEALING ATMOSPHERE Annealing is a straightforward process but also requires careful control of temperature gradients and atmosphere composition. Air ingress at furnace entry and exit points can create oxidizing conditions, leading to surface reactions. With the thermodynamic background described before and years of experience on annealing atmosphere practice, Air Products developed an atmosphere control system for annealing atmospheres that measures the oxygen and hydrogen in the atmosphere and calculates the
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