Effect of Dewpoint on the Evolving Spectral Emissivity of Advanced High-Strength Steel During Intercritical Annealing

Pyrometry errors associated with imperfectly known spectral emissivity cause temperature variations during the intercritical annealing of advanced high-strength steels (AHSS), leading to substandard mechanical properties. Accurate pyrometry requires precise knowledge of the spectral emissivity, which unfortunately varies with several parameters, including the changing surface state produced by the dewpoint of the annealing atmosphere. This paper studies the effect of the annealing atmosphere on the radiative properties of AHSS using in-situ spectral emissivity measurements from samples annealed within an N2-H2 atmosphere at dewpoints ranging from -30°C to +10°C, providing insight toward developing emissivity models for improved pyrometry of AHSS.

Fatima Suleiman | University of Waterloo
 

Nishant Narayanan | University of Waterloo
 

Kyle Daun | University of Waterloo