Sensor tracks low-pressure carburizing

Since the end of the 1980s, methods have been available for feedback control of atmospheric carburizing treatments. Many of them rely on sensors that monitor and control carbon potential at atmospheric pressure. If a problem occurs during carburizing, such as a temperature or pressure drop, the control program intervenes to change the length of the cycle of the composition of the atmosphere. The use of such systems produces more uniform and consistent results. However, no such methods exist for controlling low-pressure or vacuum carburizing treatments. Existing carbon potential sensors cannot be applied, usually because of the absence of thermodynamic equilibrium. Although low-pressure carburizing can be more efficient than atmospheric carburizing, the lack of suitable sensor-based controls stands in the way of its further development. The sensor described here was designed to help solve this problem.