Papers by Author: F.J. Avellaneda

Abstract: TRIP steels, or Transformed Induced Plasticity steels, have excellent mechanical properties if compared with conventional steels. The highlighted characteristic of these steels is that they modify the microstructure with the deformation process as part of the austenite transforms to martensite, with the consequent change of the material properties. One of the main problems of TRIP steels is strong elastic recovery, or springback, after forming. In this work, the springback phenomenon is evaluated by bending tests and the influence of the variables involved in it is determined. Experimental bending forces do not agree with theoretical predictions that are proposed in the literature. In spite of the bending radius having been considered an influence factor in the process, this work demonstrates that the aforementioned factor has a minor influence, at least for TRIP 800. The factor found to affect material recovery the most was the bending angle.

Abstract: As it is well-known, TRIP 800 steels modify their structure with the deformation grade. So, part of the retained austenite turns into martensite by plastic deformation. The usual techniques tried out to evaluate this transformation whether do not lead to obtain good results or the experimentation with them is very complex. In this work, a magnetic induction method is experimented and developed in order to determine the evolution of a TRIP 800 steel microstructure with the strain grade. The variables that can have influence on this kind of analysis methodology have been studied and their effects evaluated. This method has been applied to determine the induced martensite by deformation under conditions of pure shear deformation. Results point that this method allows to state that the microstructure evolution taking place in TRIP 800 steels is not proportional to the strain applied.