New Sensor Concepts for Enhancing Heat Treatment Processes and Analysis

The need for developing accurate quenching models requires an extensive experimental database that includes surface heat flux characterization. Quantification of the quenching process permits i) the development of high-quality heat treated products, ii) the evaluation of new quenchants and quenchant systems, and iii) the evaluation of quenchant quality over usage time. The surface heat transfer coefficient (or heat flux) is rarely measured, calculated or modeled in sufficient detail for real scientific use. Many single-thermocouple based probes are designed for the purpose of measuring the cooling power of a liquid quenchant or for monitoring quenchant quality. Lumped based probes are sufficient for these types of applications. However, the lack of sufficient distributed detail impedes the development of future high-quality heat-treated products. Frankel and his coworkers are developing a new family of transient thermal-rate sensors that will improve both diagnostic and real-time analyzes in heat transfer studies. Analyzes have been performed indicating that there exists a novel, thermal-rate sensor hierarchy that stabilizes predictions when used with analysis. This concept can be used for investigating both (i) direct surface heat transfer effects, and (ii) projective surface analysis based on embedded sensors. This new sensor family includes the ability to measure temperature, T; heat flux, q"; and their temporal derivatives, i.e., dT/dt, d^T/dt2 and dq’Vdt.