The Role of Intercritical Jominy Test in The Development of DP and TRIP Steels
M. Réger, B. Verő, Zs. Csepeli, C.H. Gür:
THE ROLE OF INTERCRITICAL JOMINY TEST IN THE DEVELOPMENT OF DP AND TRIP STEELS,
1st International conference on heat treatment and surface engineering of tools and dies, IFHTSE 2005 (08 – 11 June 2005, Pula, Croatia)
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 product 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.