Journal of the Japan Society for Technology of Plasticity
Online ISSN : 1882-0166
Print ISSN : 0038-1586
ISSN-L : 0038-1586
Effects of Microstructure on Stretch Flangeability of High-Strength Hot-Rolled Steel Sheet by Flat-Bottomed Cylindrical Punch Forming
Yasuhiro ITOYoshiaki NAKAZAWA
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2013 Volume 54 Issue 626 Pages 272-276


Hole expansion test using a flat-bottomed cylindrical punch was carried out to clarify the effects of the difference in microstructure between two types of complex-phase high-strength hot-rolled steel sheet on stretch flangeability, in which ferrite-pearlite steel and ferrite-bainite steel of 590 MPa tensile strength were used. The results showed that the hole expansion ratio λ in the case of the hole of a reamer edge depended on fracture limit strain, which changed with the fracture behavior. Moreover, by investigating the correlation between the quality of material around the hole and λ of the sheared hole, it was clarified that the λ of ferrite-bainite steel is affected by work hardening, and that the λ of ferrite-pearlite steel is affected by microvoids generated in piercing.

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© 2013 The Japan Society for Technology of Plasticity
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