Experimental characterization of the formability properties of steel plates; Caracterizacion experimental de las propiedades de formabilidad de chapas de acero

The concept of the formability limit curve (FLC) is a very useful tool in the characterization of plates and their ability to be stamped, embedded or deformed by stretching. The formability limit is represented in most characterizations, and is a concept originally proposed by Keeler and Backhofen, and Goodwin, as a line. But this is an inexact representation, since the data are greatly dispersed due to the different phenomena involved and the experimental methodology used. For this reason the experimental determination of the FLC requires many measurements, in order to be reliable. This work presents the experimental techniques that were chosen and the experimental devices that were implemented for measuring the FLC. Measurements with a semispherical punch on different geometrically shaped samples are presented, together with uniaxial traction tests to determine the directional load curves and the Lankford coefficient values. The methodologies used to test compression and flat deformation are also described in less thick samples like the plates in the study. This full characterization of the shaping properties is discussed in order to evaluate what measurements are enough to provide the data needed to calculate a model for the FLC, using crystalline plasticity coupled with the Marciniak-Kuczynski model. Galvanizad steel plates were used in this study, with the right quality for deep embedding. The FLC and the Lankford coefficient values obtained are typical of this material. The dispersion of the results corresponds to values previously reported by different authors. The uniaxial tests show a high uniformity of flow tension in all directions on the plan compared to the plate's laminated direction, and the compression experiments on the thickness show a load curve that is approximately 25% higher than the one for the traction on the plane of the plate (au)