Punching of ultra-high strength steel sheets using local resistance heating of shearing zone
Punching of ultra-high strength steel sheets using local resistance heating of shearing zone
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DOI：
10.1016/j.jmatprotec.2011.10.021
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发表时间：
2012-02
影响因子：
6.3
通讯作者：
K. Mori;T. Maeno;S. Fuzisaka
中科院分区：
文献类型：
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作者：
K. Mori;T. Maeno;S. Fuzisaka
提出了一种利用剪切区局部电阻加热的超高强钢板冲压成形工艺。通过在板保持器和脱模器之间通电流来加热剪切区，以降低剪切中的流动应力，并且通过在加热期间不与板接触来防止模具和冲头的加热。采用具有单独弹簧的电极针来实现剪切区的均匀加热。对Ag-W、Cu-W、Ag+WC和W的电极销的头部通过加热到板的焊接电阻进行了检查。采用焊接阻力最高的Cu-W合金销对980 MPa级超高强度钢板进行了冲压试验。冲压载荷通过加热而显著降低，例如，约为800°C时冷冲压载荷的1/5。随着加热温度的升高，剪切刃上光亮磨光面的深度增加，粗糙断口的深度减少。
A punching process using local resistance heating of a shearing zone was developed to shear ultra-high strength steel sheets. The shearing zone was heated by passing electric current between the sheet holder and the knockout in order to decrease the flow stress in the shearing, and the heating of the die and punch was prevented by no contact with the sheet during the heating. Electrode pins having an individual spring were employed to attain uniform heating of the shearing zone. The welding resistance of the heads of the electrode pins to the sheet by the heating was examined for Ag–W, Cu–W, Ag+WC and W. The Cu–W pins having the highest welding resistance were employed in a punching experiment of 980MPa level ultra-high strength steel sheets. The punching load was considerably reduced by the heating, e.g., about 1/5 of the cold punching load at 800°C. As the heating temperature increased, the depth of the shiny burnished surface on the sheared edge increased and that of the rough fracture surface decreased.