High quality ISUZU NKR Rear Hub Bolt

1.Spheroidizing annealing of high-strength bolts

When the hexagon socket head bolts are produced by the cold heading process, the original structure of the steel will directly affect the forming ability during cold heading processing. Therefore, the steel must have good plasticity. When the chemical composition of the steel is constant, the metallographic structure is the key factor determining the plasticity. It is generally believed that the coarse flaky pearlite is not conducive to cold heading forming, while the fine spherical pearlite can significantly improve the plastic deformation ability of the steel.
For medium carbon steel and medium carbon alloy steel with a large amount of high-strength fasteners, spheroidizing annealing is performed before cold heading, so as to obtain uniform and fine spheroidized pearlite to better meet the actual production needs.

2.high-strength bolt drawing

The purpose of the drawing process is to modify the size of the raw materials, and the second is to obtain the basic mechanical properties of the fastener through deformation and strengthening. If the distribution of the reduction ratio of each pass is not appropriate, it will also cause torsional cracks in the wire rod wire during the drawing process. In addition, if the lubrication is not good during the drawing process, it can also cause regular transverse cracks in the cold drawn wire rod. The tangent direction of the wire rod and the wire drawing die at the same time when the wire rod is rolled out of the pellet wire die mouth is not concentric, which will cause the wear of the unilateral hole pattern of the wire drawing die to aggravate, and the inner hole will be out of round, resulting in uneven drawing deformation in the circumferential direction of the wire, making the wire The roundness is out of tolerance, and the cross-sectional stress of the steel wire is not uniform during the cold heading process, which affects the cold heading pass rate.