Effects of Silicon and Manganese Contents on Deep Drawig of Ultrahigh-Strenght Transformation-Induced Plasticity-Aided Dual-Phase Sheet Steels

摘要

The effects of retained austenite on deep drawing in high-strength transformation-induced plastifcity-aided dual-phase (TD[) sheet steels with different silicon and mangansse contents were investigated. The deep drawability evaluated based on the limiting drawing ratio (LDR) was affected by the volume fraction of the retained austenite rather than by its stability and morphology. Namely, the higher the volume fraction of the retained austenite, the greater the strength-deep drawability balance, i.e. the product of tensile strength and LDR. The excellent deep drawability was due to high local mecking resistance at the cup wall ust above the punch bottom due to "transformation hardening' stress relaxation" resultsing fromteh strain-induced martensite transformation, as well as to the low drawing resistance of the shrinking flange.