Impact of second phase morphology and orientation on the plastic behavior of dual-phase steels

The properties of the dual-phase steels are attributed to the chemical composition, type, size, amount, and spatial distribution of different phases that can be obtained during thermomechanical treatments. In this way, modeling of the mechanical behavior of the dual-phase steel constituents, namely, ferrite and martensite, is crucial to the numerical simulation of sheet metal forming processes mainly to forecast the residual stresses per phase. In this work, the microstructure of as-received DP600 and DP800 cold rolled steel sheets with 1.2 mm nominal thickness were firstly characterized by means of scanning electron microscopy technique. The grain sizes and volume fractions of ferrite and martensite phases were obtained by means of digital image analysis. The Mori-Tanaka homogenization scheme was implemented in the finite element code ABAQUS assuming linear isotropic elasticity and isotropic work-hardening behavior for both ferrite (matrix) and martensite (inclusion) phases. The numerical predictions obtained with the Mori-Tanaka homogenization scheme for the macroscopic uniaxial tensile behavior are in good agreement with the experimental curves of both dual-phase steels.

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Effect of morphology of second-phase martensite on tensile properties of Fe-0.1C dual phase steels

Journal of Materials Science ◽

10.1007/bf00580148 ◽

1990 ◽

Vol 25 (12) ◽

pp. 5179-5184 ◽

Cited By ~ 61

Author(s):

Yoshiyuki Tomita

Keyword(s):

Tensile Properties ◽

Second Phase ◽

Dual Phase ◽

Dual Phase Steels

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Microstructural Characterization of Dual and Multiphase Steels Applied to Automotive Industry

Materials Science Forum ◽

10.4028/www.scientific.net/msf.775-776.146 ◽

2014 ◽

Vol 775-776 ◽

pp. 146-150 ◽

Cited By ~ 1

Author(s):

Cristina Sayuri Fukugauchi ◽

Antonio dos Reis Faria Neto ◽

Rosinei Batista Ribeiro ◽

Marcelo dos Santos Pereira

Keyword(s):

Mechanical Properties ◽

Microstructural Characterization ◽

Tensile Tests ◽

Ferrite Matrix ◽

Microstructure Characterization ◽

Second Phase ◽

Dual Phase ◽

Dual Phase Steels ◽

Trip Steels

TRIP (Transformation Induced Plasticity) and DP (Dual-Phase) steels are written in a new series of steels which present excellent mechanical properties. As for microstructure aspect, TRIP steels consist on a ferrite matrix with a second phase dispersion of other constituents, such as bainite, martensite and retained austenite, while dual-phase steels consist on martensite dispersion in a ferrite matrix. In order to identify the different microconstituents present in these materials, microstructure characterization techniques by optical microscopy (using different etchants: LePera, Heat-Tinting and Nital) and scanning electron microscopy were carried out. This being so, microstructures were correlated with mechanical properties of materials, determined by means of tensile tests. It is concluded that steels assisted by TRIP effect have a strength and elongation relation higher than the dual-phase one. With microstructure characterization, it was observed phases present in these materials microstructure.

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Texture Evolution during Cold Rolling and Annealing in Dual Phase Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.702-703.778 ◽

2011 ◽

Vol 702-703 ◽

pp. 778-781 ◽

Cited By ~ 2

Author(s):

Jai Gautam ◽

Alexis G. Miroux ◽

Jaap Moerman ◽

Carla Barbatti ◽

Leo Kestens

Keyword(s):

Phase Transformation ◽

Cold Rolling ◽

Texture Evolution ◽

Rolling Texture ◽

Recovery Process ◽

Second Phase ◽

Dual Phase ◽

Dual Phase Steels ◽

Initial Stage ◽

Cold Rolling And Annealing

This paper investigates the bulk texture evolution during cold rolling and annealing of Dual Phase steels for different processing conditions, i.e. cold reduction within the reduction range of 45 to 73% and annealing at temperatures between 650 and 850°C, which includes the recovery, recrystallisation and partial phase transformation domains. Textures have been measured by X-ray diffraction. The results reveal that the rolling texture is strengthened during the recovery process or initial stage of recrystallisation while during recrystallisation a weak RD-ND type of texture appears. During subsequent phase transformation the RD-ND type of texture further weakens and later randomises as the second phase fraction increases beyond 75%.

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Effects of Second Phase Morphology on RetainedAustenite Morphology and Tensile Properties in a TRIP-aided Dual-phase Steel Sheet.

ISIJ International ◽

10.2355/isijinternational.33.775 ◽

1993 ◽

Vol 33 (7) ◽

pp. 775-782 ◽

Cited By ~ 160

Author(s):

Koh-ichi Sugimoto ◽

Masahiro Misu ◽

Mitsuyuki Kobayashi ◽

Hidenori Shirasawa

Keyword(s):

Tensile Properties ◽

Steel Sheet ◽

Dual Phase Steel ◽

Phase Morphology ◽

Second Phase ◽

Dual Phase

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Simulation of Evolution of Dual-Phase Microstructure

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.2652 ◽

2010 ◽

Vol 638-642 ◽

pp. 2652-2657 ◽

Cited By ~ 1

Author(s):

Stan T. Mandziej ◽

Sebastian Waengler ◽

Julio Noack ◽

Rudolf Kawalla

Keyword(s):

Grain Size ◽

Physical Simulation ◽

Cold Forging ◽

Chemical Compositions ◽

Second Phase ◽

Dual Phase ◽

Dual Phase Steels ◽

Austenite Grain Size ◽

Cold Forming ◽

Average Grain Size

Dual-phase steels, developed in the 1970’s, found until now wide applications related to their optimum combination of strength and ductility, in particular as flat semi-products used for further shaping by deep drawing and cold forming operations. Actually the need appears to manufacture long semi-products of dual-phase steels for further processing by cold forging, in order to obtain high-strength final products, like e.g. fasteners, without additional heat-treatment. An additional aim has been to explore the possibility of achieving from the same chemical compositions dedicated properties for particular applications. In this work a thermo-mechanical route was developed of modifying an originally bainitic-martensitic low-alloy steel to achieve a dual-phase microstructure. For this purpose physical simulation was used on Gleeble 3800 thermal-mechanical simulator, programmed to affect austenite in its dynamic recrystallisation range followed by separation of microstructures in the two-phase austenite-ferrite range. Observation of relaxation was used to monitor advancement of transformation / recrystallisation in subsequent stages of the processing. In the simulated hot-warm rolling process it appeared possible to convert the original bainitic microstructure, having prior austenite grain size ~15μm and the martensite-bainite laths of usual length throughout these grains, to the dual-phase microstructure containing well-recrystallised ferrite of an average grain size 1*1.5μm and fine second-phase islands of less than 1.0μm diameter. SEM and TEM analysis have been applied to describe details of the resulting microstructures.

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