Nodular cast iron material of automobile steering knuckle and preparation method of nodular cast iron material

The invention discloses a nodular cast iron material of an automobile steering knuckle and a preparation method of the nodular cast iron material, the nodular cast iron material comprises the following components in percentage by mass: 60-62% of pig iron, 36-38% of Q235 steel, 1-1.4% of a carburant, 0.3-0.5% of silicon iron, 0.4-0.5% of electrolytic copper and 0.02-0.05% of tin, and the nodular cast iron material comprises the following chemical components in percentage by mass: 3.75-3.9% of C, 1.4-1.5% of Si, 0.5-0.6% of Mn, less than or equal to 0.025% of S, less than or equal to 0.05% of P, 0.55-0.65% of Cu, 0.025-0.03% of Sn and the balance of iron and other inevitable impurities. The automobile steering knuckle is produced through the steps of burdening, smelting, molten iron detection, spheroidizing and pouring. A casting produced from the nodular cast iron material is good in mechanical property and hardness, and meets the requirements of steering knuckles of some commercial vehicles, especially the pr