A numerical study of an insulating end-quench test for high hardenability steels

A numerical model is presented to determine the heat transfer, phase transformation and hardness distribution of extension Jominy bars in an insulating end-quenching test designed to evaluate the hardenablility of steels having middle or high hardenability. The end-quenching test is conducted in a revised device with a refractory insulating liner to decrease the cooling rate of the specimen. Heat transfer coefficients varying not only with temperature of end surface but also with radius are adopted when examining the water jet on the end side. A modified model based on Avrami equation and Koistien‐Marburger law is developed to determine the microstructure distribution, and an empirical based formula developed by Maynier is applied to calculate the Vickers hardness of each phase at different cooling rate. The microstructure and hardness predictions obtained in the present model are found to be in good agreement with experimental measurements.