Outlines the method for determination of hardenability of steels by end-quenching and hardness determinations. It includes information on the preparation of standard and subsidiary test pieces, test equipment, heat-treatment details and subsequent hardness testing. Requirements for the specification of hardenability limits are included. Heat-treatment temperatures for wrought alloy steels of the AISI-SAE type H series and typical hardenability charts for recording data are in appendices.