Hot-rolled wire rod for 70-grade steel cord, preparation method of hot-rolled wire rod and automobile tire

The invention provides a hot-rolled wire rod for a 70-grade steel cord, a preparation method of the hot-rolled wire rod and an automobile tire, and belongs to the technical field of metal materials, and the hot-rolled wire rod for the 70-grade steel cord comprises the following chemical components: C, Si, Mn, P, S, Cr, B, Nb, Fe and impurities from the preparation of the hot-rolled wire rod for the 70-grade steel cord; wherein, by mass fraction, the value of (Mn + Nb)/Si is 2.5 to 3.5, and the value of (Cr + Nb) is 0.06 to 0.09%. The value of (Mn + Nb)/Si is limited to be 2.5-3.5, so that it is ensured that the hot-rolled wire rod for the 70-grade steel cord has excellent strength and plasticity; meanwhile, the value of (Cr + Nb) is limited to be 0.06%-0.09%, so that it is ensured that the hot-rolled wire rod for the 70-grade steel cord has excellent hardenability, and the sorbite content is increased; therefore, the drawability of the hot-rolled wire rod for the 70-grade steel cord is effectively improved. 本