J. Phys. IV France 125 (2005) 523-526
Inspection of an end quenched plain steel Jominy bar with photothermal radiometric techniquesY. Liu, N. Baddour, A. Mandelis and C. Wang
Center for Advanced Diffusion Wave Technologies, Department of Mechanical and Industrial Engineering University of Toronto, 5 King's College Road, Toronto, ON, M5S 3G8, Canada
The effect of the cooling rate on hardness and thermal conductivity in a metallurgical Jominy bar made of AISI 1018 steel, by means of a water end-quenched heat treatment process without diffusion-controlled case depth, is studied with photothermal radiometry (PTR). It is concluded that our two PTR techniques, common-mode rejection demodulation (CMRD) and conventional 50% duty-cycle square-wave frequency scan, are sensitive to low hardness values and gradients, unlike the high values all previous photothermal studies have dealt with to-date. Both PTR methods have yielded an anti-correlation between thermal conductivity and microhardness in this case as in previous cases with heat-treated and diffusion-controlled case depth profiles. It is shown that the cooling rate strongly affects both hardness and thermal conductivity in the Jominy-bar heat-treating process.
© EDP Sciences 2005