Abstract: Disclosed is a method of fabricating spheroidal graphite cast iron parts including a) preparing a mixture in the liquid state having the following composition by weight: 3% to 4% C; 1.7% to 3% Si; 0.1% to 0.7% Mn; 0 to 4% Ni; 0 to 1.5% Cu; 0 to 0.5% Mo; with a residual Mg content adapted to the thickness of the parts and lying in the range 0.025% to 0.080%; the balance being iron and impurities; b) casting this liquid mixture at a temperature in the range 1350° C. to 1550° C. into a mold to obtain a blank; c) extracting the blank from the mold at a temperature between the solidus and AR3, where the solidus and AR3 represent the limit temperatures for the austenitic range of the composition, or at a temperature less than AR3; d) shaping the blank at a temperature in the range 1050° C. to AR3; e) cooling to a temperature lying in the range 260° C. to 420° C. situated in the bainitic range, and maintaining this temperature for 60 min to 180 min, and cooling to ambient temperature.