Heat Tranfer at Quenching Period (3rd Report)

Abstract

We intend to report in the present paper as to how the coefficients of heat transfer α obtained from our previous quenching experiments are applied to hardening of carbon steels. At quenching period the test bodies were rapidly cooled through the three stages, film state boiling, bubble state boiling and natural convection. Comparing the values of α_min (at film state boiling) and α_max (at bubble state boiling) with the hardenability of carbon steels, we have found that strong quenching media like NaCl aqueous solution and cold water, have higher values on α_min and α_max, and soft quenching media like mineral oil, have comparatively higher values on α_min in spite of their lower values on α_max.