The Jominy End-Quench Test - Laboratory 5 | MAT E 443, Lab Reports of Materials science

Download The Jominy End-Quench Test - Laboratory 5 | MAT E 443 and more Lab Reports Materials science in PDF only on Docsity! Mat E 443 – Laboratory 5: The Jominy End-Quench Test Background As we have discussed previously in this course, hardenability is one of the most important properties of a steel because it describes the ease with which a given steel can be quenched to form martensite or the depth to which martensite is formed on a given quench. In Laboratory exercise #3, we used different quench media to examine the hardness and microstructural gradients that are generated upon quenching round bars of differing diameter. Further, we determined the critical diameter (dc) for selected steels and ascertained the ideal diameter (DI) for these materials. This type of experiment requires multiple austenitization and quenching treatments on specimens of varying diameter just to quantify the hardenability of a single material. An alternative approach is to develop a more convenient standard test method that can be used for relative comparison of hardenability. The Jominy end-quench test is one such approach. The jominy end-quench test is specified in ASTM standard A255 and is a widely used method for quantifying hardenability. Its wide use adds to its value, since the utility of empirical relations and data comparison becomes more reliable as more data are accumulated. Moreover, jominy data have been collected on a large enough scale to offer a high degree of statistical certainty for many steels. These data have been correlated with measurements and/or calculations of dc. By using these correlations, a single jominy test can be used to estimate dc and DI for a given steel (and austenite grain size).