Quenching is the rapid cooling of a metal to obtain certain properties such as microstructure, hardness, and residual stresses which in turn leads to certain strength characteristics, abrasion resistance, etc. For this, regular control and monitoring of such cooling process, interaction between material composition, on the one hand, and the size and shape of the part, its surface characteristics, and the temperature-time sequence, etc., on the other, is necessary. Cooling capacity and quenching characteristics are evaluated and assessed using cooling curves. From this, the heat transfer coefficient, a measure of the quenchant's capacity to transfer heat from the surface of the quenched component, can be obtained. Measurements and development of cooling curves and standards for performing the same are described. Analysis of cooling curves and influence of process parameters, aging, and contaminations on cooling characteristics for oils and polymers are also covered. © 2014 Elsevier Ltd All rights reserved.