To improve the deep drawing of high-strengthTRIP-aided dual-phase (TDP) sheet steel, Swirl cup test of a0.19C-1.54Si-1.52Mn (mass%) TDP steel was investigated attemperatures between 20。 C and 250。 C. The steel exhibited alarger limiting drawing ratio (LDR) than those of theconventional ferrite-bainite and ferrite-martensite dual-phasesteels without retained austenite. Furthermore, the LDR was enhanced bywarm drawing at about 150。 C, at which the strain-inducedtransformation of the retained austenite particles is suppressedmost. Such excellent deep drawabilily was caused by large localnecking resistance due to "the transformation hardening" and"the stress relaxation" resulting from the strain-inducedmartensite transformation at the cup wall just above the punchbottom, as well as low drawing resistance of the shrinking flange.
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