title = "Temperature Measurement: Thermocouples and Pyrometers"

content = """
Accurate and traceable temperature measurement is fundamental to heat treatment quality. All heat treatment processes at Ridgecrest Metalworks require temperature measurement devices that are calibrated, maintained, and documented per the requirements of AMS 2750 (Pyrometry—the aerospace and automotive heat treatment standard) and applicable customer or regulatory requirements.

Thermocouples are the primary temperature measurement device for heat treatment furnaces. A thermocouple consists of two dissimilar metal wires joined at one end (the measuring junction); the voltage generated at the junction is a function of temperature. Type K (chromel-alumel) is the most widely used general-purpose thermocouple for temperatures up to 2300°F (1260°C). Type N (nicrosil-nisil) offers better stability and longer life at high temperatures. Type R and Type S (platinum-rhodium) are used for higher temperatures and in precision applications where greater accuracy is required. Type J (iron-constantan) is used for lower temperatures (up to 1400°F).

Thermocouple grade: standard-grade thermocouples are used for temperature controllers and recording. Special-grade (tolerance ±1°F or ±0.5°C) or prime-grade thermocouples are used for load thermocouples and calibration. Extension wire used between the thermocouple and the instrument must match the thermocouple type; using incorrect extension wire introduces significant errors.

Thermocouple calibration and replacement schedules are prescribed by AMS 2750 based on furnace class (temperature uniformity requirements) and process type. Thermocouples used for load temperature measurement (inside the furnace with the load) are single-use or limited-use and are replaced after each cycle or weekly.

System accuracy tests (SAT) per AMS 2750 verify the complete measurement system (thermocouple + extension wire + instrument) against a calibrated reference. Temperature uniformity surveys (TUS) verify that all locations inside the furnace qualified working zone meet the temperature uniformity tolerance (±10°F / ±5.5°C for Class 3 commercial heat treatment; ±5°F / ±2.8°C for Class 2 aerospace).

Optical (radiation) pyrometers measure temperature by detecting thermal radiation emitted by the surface—essential for measuring temperature contactlessly for moving parts (induction hardening, rolling, forging). Emissivity of the surface must be calibrated or adjusted for accurate readings.
"""

version = "0.0.1"
