Method for manufacturing a metal workpiece limiting the appearance of recrystallized grains in said workpiece

A method for manufacturing a metal workpiece by casting a metal alloy in a mold, wherein prior to said casting, a chart is determined providing a risk of appearance of recrystallized grains during the casting and/or solidification of the metal workpiece, depending on temperature and plastic deformation energy conditions undergone by said metal workpiece, said chart being obtained by implementing the following steps:

• mechanical test on a test piece so as to characterize a plastic deformation of said test piece according to different values of imposed stresses;
• thermal treatment of said test piece, then macrographic etching to determine an appearance of recrystallized grains in the test piece;
• and
• calculation, according to stress values measured during the mechanical test, of a plastic deformation energy in the test piece, the plastic deformation energy being plotted as a function of the temperature during the mechanical test, with information relating to a presence of recrystallized grains, so as to constitute the chart;
• the casting of the metal alloy in the mold is then carried out in order for the temperature and plastic deformation energy conditions undergone by said metal workpiece to be manufactured to be less than a given threshold for the risk of appearance of determined recrystallized grains according to the chart.