The effects of warm hole-punching and warm hole-expanding on stretch-flangeability of a TRIP-aided dual-phase (TDP) steel sheet were investigated. Excellent stretch-flangeability, whose value nearly corresponded to that of drilling hole, was performed by warm hole-punching and hole-expanding at about 150℃. The warm punching decreased strain-induced martensite content and/or void initiation at the martensite/matrix interface in a layer region of the hole surface. The minimum depth of the damage layer reduced up to a clearance between punch and die.
変態誘起塑性型高強度複合組織鋼板の温間穴拡げ成形性
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nagano_nct-28-03.pdf
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