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Effects of Mn Content on the Warm Stretch‐Flangeabiliy of C–Si–Mn TRIP‐Aided Steels
Author(s) -
Sugimoto Kohichi,
Hidaka Shinnosuke,
Tanino Hikaru,
Kobayashi Junya
Publication year - 2017
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201600482
Subject(s) - materials science , austenite , microstructure , martensite , metallurgy , ductility (earth science) , punching , plasticity , composite material , creep
Effects of Mn content on warm stretch‐flangeability are investigated using 0.2%C–1.5%Si–(1.5–5.0)% Mn transformation‐induced plasticity (TRIP)‐aided sheet steels with annealed martensite matrix. Warm hole‐expansion at 150–250 °C after hole‐punching at 25 °C enhances the stretch‐flangeability of 3 and 5% Mn steels. The warm stretch‐flangeability increases with the Mn content. The superior warm stretch‐flangeability of hole‐punched 5% Mn steel is caused by its large localized ductility on expanding, which results primarily from the stabilization of its large quantity of retained austenite and its fine microstructure. Use of hole‐drilling instead of hole‐punching at 25 °C further increases the stretch‐flangeability and raises the optimum expanding temperature to 250–300 °C.