title = "Industrial Furnace Maintenance and Refractory Care"

content = """
Industrial furnaces at Ridgecrest Metalworks are used for heat treatment (annealing, normalizing, hardening, and tempering of steel) and for powder coat curing. Furnace reliability and temperature uniformity are critical to achieving consistent metallurgical results and coating quality.

Electrical resistance furnaces (box furnaces, pit furnaces): Heating elements (silicon carbide, MoSi₂, or metallic alloy resistance wire) degrade over service life. Visual inspection of elements during cool-down reveals cracked or burnt-out elements requiring replacement. Element resistance should be measured annually; significant deviation from the nominal resistance indicates deterioration. Control thermocouples are the critical sensing element: thermocouples drift over time and must be replaced at defined intervals (typically annually for Type K in high-temperature service above 900 °C) or when the furnace fails temperature uniformity survey.

Gas-fired furnaces: Burner nozzles and flame tubes are inspected quarterly for blockage, erosion, and cracking. Combustion air/gas ratio is checked and adjusted by measuring flue gas composition (O₂ and CO content); incorrect ratio causes excessive fuel consumption, overheating (excess air causes localized hot spots), or carbon monoxide hazard (under-firing). Combustion controls (flame supervision relays, gas train solenoids, pressure switches) are tested for correct function per the annual safety inspection.

Refractory maintenance: Furnace interiors are lined with refractory brick, castable refractory, or ceramic fiber modules. Refractory is inspected at each furnace cool-down for cracks, spalling (surface flaking), and hot spots (glowing through the shell indicates refractory thinning or breach). Small cracks in castable refractory are repaired with refractory mortar while hot or immediately after cool-down. Ceramic fiber modules or blanket that have become rigid and friable (degraded by temperature or chemical attack) are replaced.

Temperature uniformity survey (TUS): Per AMS 2750 (aerospace) or CQI-9 (automotive), furnaces used for heat treatment of critical parts must pass a temperature uniformity survey at defined intervals. The TUS measures temperature at multiple points inside the working zone simultaneously using calibrated thermocouples. All points must be within the specified uniformity tolerance (e.g., ±5 °C for Class 2 furnaces under AMS 2750) at the operating setpoint. Failed TUS requires furnace repair and re-survey before returning to qualified service.
"""

version = "0.0.1"
