High strength Volvo Wheel Bolt 20515514

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.