Evolution of Microstructural Banding during the Manufacturing Process of Dual Phase Steels

Abstract

The segregation of manganese during solidification from casting is responsible for banding problems of dual phase steels. Microstructural banding lasts during all the manufacture process, producing the deterioration of the material, so the final ductility and impact toughness of the sheets are decreased due to the high level of anisotropy. To avoid or reduce the problem of microstructural banding, it is proposed to modify the hot rolling parameters so the formation of ferrite-pearlite microstructures is avoided and thus the presence of banding. The study of the microstructural evolution during the whole manufacturing process reveals that the increase of the cooling rate during the hot rolling leads to a significant decrease of martensite banding in the microstructure of dual phase steels for sheets used in the automotive industry.

Influence of austenite grain size on overaging treatment of continuous annealed dual phase steels

“…This microstructure is mainly formed by ferrite (72 vol.%), with some randomly dispersed martensite (16 vol.%) and pearlite (12 vol.%). Although some martensite is present and the quantity of pearlite is smaller in this microstructure than in the as-received microstructure, it is expected that these differences will not affect significantly the kinetics of the austenite formation during the intercritical annealing 17 . As it was intended, the resulting grain size has decreased compared with the original sample, since the average ferrite grain size in this case was measured to be 5m.…”

Deformation-Induced Microstructural Banding in TRIP Steels

“…[8] Nevertheless, a better understanding of the effects of such bands on the microstructural behavior of TRIP steels can lead to the development of new processing routes aimed at improving the mechanical properties of these materials by optimizing the geometric characteristics of these bands. [3,9] Furthermore, some optimizations can be realized through economically feasible thermomechanical processes. [3,9] For example, it has been suggested that increasing the cooling rate during the hot rolling process leads to a significant decrease of martensite banding in the microstructure of dual-phase steels for sheets used in the automotive industry.…”

“…[3,9] Furthermore, some optimizations can be realized through economically feasible thermomechanical processes. [3,9] For example, it has been suggested that increasing the cooling rate during the hot rolling process leads to a significant decrease of martensite banding in the microstructure of dual-phase steels for sheets used in the automotive industry. [9] The influence of microstructural bands on the global material behavior of banded and un-banded microstructures has been widely investigated in the literature with differing conclusions.…”

“…[3,9] For example, it has been suggested that increasing the cooling rate during the hot rolling process leads to a significant decrease of martensite banding in the microstructure of dual-phase steels for sheets used in the automotive industry. [9] The influence of microstructural bands on the global material behavior of banded and un-banded microstructures has been widely investigated in the literature with differing conclusions. The effect of such bands on local deformation and damage has been reported to be both detrimental and beneficial.…”

Investigation of the Microstructural Banding in Steel 4140

“…Много-численные работы, посвященные проблеме структурной полосчатости, позволили понять механизм формирования полос. Однако предлагаемые технологические решения, позволяю-щие уменьшить отрицательное влияние структурной полосчатости [4,18,19] или полностью устранить причину ее образования [20,21], не всегда целесообразны [3], а в ряде случаев технологически не реализуемы [22]. структуры [15,[26][27][28], что весьма актуально при обеспечении надлежащего качества готовых ответственных изделий.…”