Effects of Microstructure on Stretch-flange-formability of 980 MPa Grade Cold-rolled Ultra High Strength Steel Sheets

  title={Effects of Microstructure on Stretch-flange-formability of 980 MPa Grade Cold-rolled Ultra High Strength Steel Sheets},
  author={Kohei Hasegawa and Kenji Kawamura and Toshiaki Urabe and Yoshihiro Hosoya},
  journal={Isij International},
Stretch-flange-formability is an important property for ultra high strength steel (UHSS) sheets for press-forming. In this study, microscopic deformation behaviors during punching and following stretch-flange-forming were investigated using three types of 980 MPa grade UHSS sheets with either two ferrite/martensite dual-phase structures or a martensite single-phase structure in order to clarify how the microstructure affects the stretch-flange-formability of UHSS sheets. The results of this… 

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