Determination of the semi-solid behavior of steels

For the low melting point alloys, it is possible to use standard laboratory methods, such us the Couette's viscometer for example, in order to determine the behavior of their semi-solid properties. The under way studies concerning the semi-solid forming of steels needs more developments of test methods adapted to "high temperatures" [1]. The description of the means used for these determinations such as materials and geometries of the forming tools, the press allowing the deformations and the inductive heating equipment, reveal the difficulties encountered in order to realize and overcome the whole parameters necessary for obtaining the accurate data. The experimental results obtained during the tests over several steel grades allow the determination, for a given deformation, of the couples of temperatures and deformation speeds delimiting the area of homogeneous material flow. The data acquisition of the deformation forces, allows also the determination of the constitutive behavior law applied in the thixoforming temperature range i.e. the temperature range between the solidus and liquidus. The implementation of this law in the simulation software (in our case the forming software's are FORGE2 an FORGE3) allows the improvement of the adequate conditions to realize the thixoforging of steels applied to carry out industrial near net shape part or simply the direct extrusion feasibility tests.