High-strength nodular cast iron part for automobile rear axle shell and preparation method for high-strength nodular cast iron part

The invention discloses a high-strength nodular cast iron part for an automobile rear axle shell and a preparation method for the high-strength nodular cast iron part. The nodular cast iron part comprises the chemical components of, by weight, 3.7%-4.2% of C, 2.6%-3.0% of Si, 0.6%-0.9% of Mn, 0.4%-0.7% of Cu, 0.5%-0.8% of Ti, 0.3%-0.5% of Zr, 0.15%-0.25% of Nb, 0.05%-0.1% of Nd, 0.04%-0.08% of Tb, 0-0.04% of P, 0-0.02% of S, and the balance Fe. According to the high-strength nodular cast iron part for the automobile rear axle shell and the preparation method for the high-strength nodular cast iron part, due to adding of the elements such as the Ti, the Zr, the Nb, the Nd and the Tb, in particular adding of the three elements of the Zr, the Nd and the Tb, the strength of the nodular cast iron part prepared through the preparation method is higher than that of a common nodular cast iron part, the tensile strength is larger than or equal to 640 Mpa, the yield strength is larger than or equal to 420 Mpa, and the