Scattering Behavior of Slivers in Shearing of Magnetized Ultra-High-Strength Steel Sheets

The changes in the magnetization properties of high-strength steel and ultra-high-strength steel sheets are investigated, and then the sheared edges and the scattering behavior of slivers in shearing of the ultra-high-strength steel sheets are observed. The maximum magnetic flux density of the magnetized sheet is increased with the increasing tensile strength of the sheet. The maximum magnetic flux density in the magnetized blanks decreases, whereas the density in the demagnetized blanks increases. In the sheared edges, the ratio of the fracture surface becomes larger with the increasing tensile strength of the steel sheet. In shearing, the shearing slivers are observed at the time of crack penetration and at the time of punch rise. The mass of the slivers generated from the blank in shearing increases with the increasing tensile strength of the steel sheet. Two-thirds of the generated shearing slivers stick to the blank in the magnetized blank, whereas two-thirds of the slivers in the blank without magnetization scatter to the outside of the die.