Micro-Alloying Effect on Cold Rolled TRIP Aided Steels

MasterIn the present study, the effect of micro-alloying (Nb,Ti) additions on the microstructure-properties relationship of Transformation-Induced Plasticity (TRIP) steels was investigated in order to improve tensile strength without deterioration of elongation and weldibility. The addition of micro-alloying elements results in sophisticated effects on the mechanical properties of TRIP steels: (1). interstitial C loss in matrix due to precipitation formation, (2).reduction of elongation due to incoherency between precipitate matrix and (3).deterioration of strain hardening resulting from smaller grain size. Thermo mechanical processing done by dilatometer were followed by an analysis of the microstructure by OM and FESEM. The retained austenite content was determined by MSAT and XRD methods. Quantitative analysis was performed by precipitate extraction method followed by ICP analysis. The precipitates were classified on the basis of amount, size, shape and distribution based on TEM with the help of carbon replica method and the results were compared with those from Mat-calc software. The effectiveness of the precipitation of the micro-alloying elements on the mechanical properties could be observed clearly