Intercritical Interrupted Jominy Test

Abstract:

The final microstructure of DP and TRIP assisted steels can evolve after hot working (hot rolling) or during post heat treatment process. In the formation of the final structure a number of different technological parameters have important role, e.g. finishing temperature of rolling, cooling rates, temperature of intercritical annealing, etc. As a result of the individual factors and their combinations a lot of production technology routes are feasible. The effect of the different combinations of these technological parameters on the microstructure can be mapped by a special Jominy end-quench test (so called intercritical Jominy end-quench test) described in this paper. Unlike the traditional Jominy test, in this case there is a partial austenizing between A1 and A3 temperatures which results in a given amount of ferrite in the microstructure before quenching. The amount of ferrite depends on the temperature. In some cases the quenching process was interrupted for a given period of time in order to model the cooling process on the run-out table. During cooling each point of the Jominy specimen has a different cooling rate, so the effect of cooling rate on the microstructure can be evaluated along the length of the specimen.