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The Effect of Bake‐Hardening Parameters on the Mechanical Properties of Dual‐Phase Steels
Author(s) -
Ramazani Ali,
Bruehl Sonja,
Abbasi Mahmoud,
Bleck Wolfgang,
Prahl Ulrich
Publication year - 2016
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.201600060
Subject(s) - materials science , martensite , ultimate tensile strength , formability , volume fraction , metallurgy , tempering , microstructure , dual phase steel , hardening (computing) , strain hardening exponent , yield (engineering) , composite material , layer (electronics)
Dual‐phase (DP) steels offer an outstanding combination of strength and formability as a result of their microstructure, in which a hard martensitic or bainitic phase is dispersed in a soft ferritic matrix. DP steels have a high ultimate tensile strength combined with a low initial yielding stress. The yield strength of DP steels is further increased by the paint baking, also called bake hardening (BH), process. In the current research, the effect of BH parameters, namely pre‐strain, baking temperature, and holding time, on yield strength increment of DP steels with different martensite volume fractions is investigated. DP steels with 20 and 30% martensite volume fraction are pre‐strained up to 5%, then they are baked at 100, 170, and 300 °C for various times. The results show that maximum yield strength is obtained as optimum values of BH parameters are applied. It is also found that at high values of baking temperature and holding time, martensite tempering effects prevail and yield strength increment decreases. The results also indicate that the increment of pre‐strain enhances the Lüders band and decreases the yield strength increment.