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
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1st International conference on heat treatment and surface engineering of tools and dies, IFHTSE 2005 (08 – 11 June 2005, Pula, Croatia)

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 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.


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