A Novel Way Refining the Partially Reverted Globular Austenite in Reversion from Martensite

Refining of the partially reverted globular austenite grain is of great importance to obtain high mechanical property of advanced high strength steels and a new approach for such refining, pre-tempering of initial martensite, is proposed in this study. The pre-tempering results in precipitation of the coarse and alloying-elements partitioned cementite particles in an Fe-2.5Mn-1.5Si-0.35C alloy. The cementite particles with Mn and Si partitioning enhanced the nucleation of globular austenite grains but suppressed its growth during continuous heating. The enhancement in nucleation and restriction in growth of globular austenite resulted in the refinement of partially reverted globular austenite grains and fully transformed austenite grains after reversion. This provides a new strategy to control the growth of partially reverted globular austenite by tailoring coarse and partitioned cementite particles.