The invention discloses a preparation method of a fastening bolt for an automobile wheel. The preparation method comprises the following
processing steps: a,
casting a
raw material, wherein the
raw material comprises the following chemical components in percentage by weight: 0.4 to 0.8% of C, 0.02 to 0.05% of Si, 0.18 to 0.21% of Mn, 0.16 to 0.18% of P, 0.05 to 0.07% of S, 0.05 to 0.15% of Cr, 0.05 to 0.12% of Ti, 0.11 to 0.13% of Cu, 0.01 to 0.02% of Al, 0.02 to 0.03% of Mg, and the balance of iron; and b, scouring the casted and formed rod material; carrying out line drawing on the rod material according to the requirement of the line
diameter of the bolt, so that the rod material shrinks to the line
diameter required by the bolt;
cutting the rod material which is shrunk to the required line
diameter to the length required by the bolt; placing the
cut rod material into a die cavity at normal temperature; and using upsetting force to enable the dimensions of a head part and a rod part of the rod material to reach the requirements of the bolt. According to the preparation method of the fastening bolt for the automobile wheel, the bolt is processed by cold extruding process, so that the strength of the bolt is improved, the
hardness value and the strength value required by the 12.9 high-strength bolt can be realized, and the
delayed fracture and the fatigue fracture of the bolt at high strength can be solved; the fastening bolt is reliable in connection and hardly broken during use, prolongs the service life, and meets the usage demand of various industries in the society to high-strength bolts.