scholarly journals Microstructure Evolution during the Production of Dual Phase and Transformation Induced Plasticity Steels Using Modified Strip Casting Simulated in The Laboratory

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 449 ◽  
Author(s):  
Zhiping Xiong ◽  
Andrii G. Kostryzhev ◽  
Yanjun Zhao ◽  
Elena V. Pereloma
Keyword(s):  
Phase Transformations ◽  
Strip Casting ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Casting Technology ◽  
Rolling Strip ◽  
Hot And Cold Rolling ◽  
Multi Phase

Instead of conventional steel making and continuous casting followed by hot and cold rolling, strip casting technology modified with the addition of a continuous annealing stage (namely, modified strip casting) is a promising short-route for producing ferrite-martensite dual-phase (DP) and multi-phase transformation-induced plasticity (TRIP) steels. However, at present, the multi-phase steels are not manufactured by the modified strip casting, due to insufficient knowledge about phase transformations occurring during in-line heat treatment. This study analysed the phase transformations, particularly the formation of ferrite, bainite and martensite and the retention of austenite, in one 0.17C-1.52Si-1.61Mn-0.195Cr (wt. %) steel subjected to the modified strip casting simulated in the laboratory. Through the adjustment of temperature and holding time, the characteristic microstructures for DP and TRIP steels have been obtained. The DP steel showed comparable tensile properties with industrial DP 590 and the TRIP steel had a lower strength but a higher ductility than those industrially produced TRIP steels. The strength could be further enhanced by the application of deformation and/or the addition of alloying elements. This study indicates that the modified strip casting technology is a promising new route to produce steels with multi-phase microstructures in the future.

Transformation Induced Plasticity Behaviors of TRIP Steels with Different Heat Treatment Processes

2010 ◽  
Vol 150-151 ◽  
pp. 118-122
Author(s):  
Fu Xian Zhu ◽  
Ming Ya Zhang ◽  
Dong Sheng Zheng
Keyword(s):  
Heat Treatment ◽  
Retained Austenite ◽  
Ferrite Matrix ◽  
Yield Ratio ◽  
Continuous Annealing ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Treatment Processes ◽  
Two Samples ◽  
Stage Heat Treatment

Two-stage heat treatment process which has guiding significance for continuous annealing TRIP steel producing was applied in this research. Different matrixes such as polygonal ferrite matrix, bainite ferrite matrix and annealed martenite matrix were obtained through different heat treatment processes. Compared the transformation-induced plasticity (TRIP) behaviors of three different tested samples，and the corresponding process for required product properties can be chosen. It was found that the needle-like retained austenite obtained in AMT steel was isolated from other microstructures while the retained austenite in the other two samples appeared to be equiaxed or network structure. The elongation, yield ratio and stability of retained austenite in AMT steel were all higher than that in PFT or BFT steels. BFT steel possesses highest tensile strength and lowest elongation while the yield ratio, RA content and carbon concentration in RA were all lowest for PFT steel.

On the Practice of the Microstructure Adjustment to Improve the Strength-Plastic Comprehensive Performance of a C-Si-Mn Alloyed High-Strength Steel

2013 ◽  
Vol 631-632 ◽  
pp. 467-471
Author(s):  
Shuang Kuang ◽  
Guo Sen Zhu ◽  
Ying Hua Jiang
Keyword(s):  
Tensile Strength ◽  
Trip Steel ◽  
Dual Phase Steel ◽  
High Strength ◽  
Residual Austenite ◽  
Ferrite Matrix ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Metastable Austenite ◽  
Multi Phase

Four continuous annealing cycles were adopted to get four kinds of multi-phase steels using 0.2C-1.5Si-1.8Mn [wt%] alloyed raw steel and the microstructures and mechanical properties were investigated. The results show that traditional ferrite-martensite dual phase steel has a tensile strength of more than 1000MPa, but has the lowest strength-plastic product of only 18GPa%. The traditional ferrite, bainite and residual austenite TRIP steel has the highest elongation of 31% and hardening exponent of 0.24, but its tensile strength is just over 800MPa. Introducing hard matrix such as acicular bainitc ferrite or martensite to replace the polygonal ferrite matrix, meanwhile introducing metastable austenite, is conducive to obtain high strength and good ductility. Those kinds of modified TRIP steel with hard matrix can reach above 20GPa% of the strength-plastic product on the 1000MPa grade.

Effect of Intercritical Annealing Temperature on Development of Cold Rolled Dual Phase Steel from Q345 Steel

2013 ◽  
Vol 313-314 ◽  
pp. 693-696
Author(s):  
Ji Yuan Liu ◽  
Fu Xian Zhu ◽  
Shi Cheng Ma
Keyword(s):  
Dual Phase Steel ◽  
Annealing Temperature ◽  
Simulation Experiment ◽  
Intercritical Annealing ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Automotive Applications ◽  
Treatment Procedure ◽  
Annealing Temperatures ◽  
Cold Rolled

Cold rolled dual phase steel was developed from Q345 steel by heat treatment procedure for automotive applications. The ultimate tensile strength was improved about 100MPa higher than the traditional cold-rolled Q345 steel in the continuous annealing simulation experiment. The microstructure presented varied characteristics in different intercritical annealing temperatures; mechanical properties were changed correspondingly as well. The chief discussions are focus on the recrystallization, hardenability of austenite and martensite transformation in the experiment.

Unraveling dual phase transformations in a CrCoNi medium-entropy alloy

2021 ◽  
pp. 117112
Author(s):  
Yujie Chen ◽  
Dengke Chen ◽  
Xianghai An ◽  
Yin Zhang ◽  
Zhifeng Zhou ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Dual Phase

Prediction of 3D Microstructure and Plastic Deformation Behavior in Dual-Phase Steel Using Multi-Phase Field and Crystal Plasticity FFT Methods

2015 ◽  
Vol 651-653 ◽  
pp. 570-574 ◽  
Author(s):  
Akinori Yamanaka
Keyword(s):  
Plastic Deformation ◽  
Crystal Plasticity ◽  
Phase Field ◽  
Deformation Behavior ◽  
Fast Fourier Transformation ◽  
Dual Phase ◽  
Dp Steel ◽  
3D Microstructure ◽  
Plastic Deformation Behavior ◽  
Multi Phase

The plastic deformation behavior of dual-phase (DP) steel is strongly affected by its underlying three-dimensional (3D) microstructural factors such as spatial distribution and morphology of ferrite and martensite phases. In this paper, we present a coupled simulation method by the multi-phase-field (MPF) model and the crystal plasticity fast Fourier transformation (CPFFT) model to investigate the 3D microstructure-dependent plastic deformation behavior of DP steel. The MPF model is employed to generate a 3D digital image of DP microstructure, which is utilized to create a 3D representative volume element (RVE). Furthermore, the CPFFT simulation of tensile deformation of DP steel is performed using the 3D RVE. Through the simulations, we demonstrate the stress and strain partitioning behaviors in DP steel depending on the 3D morphology of DP microstructure can be investigated consistently.

Effect of Tailoring Martensite Shape and Spatial Distribution on Tensile Deformation Characteristics of Dual Phase Steels

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
B. Ravi Kumar ◽  
Vishal Singh ◽  
Tarun Nanda ◽  
Manashi Adhikary ◽  
Nimai Halder ◽  
...  
Keyword(s):  
Grain Size ◽  
Spatial Distribution ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Void Formation ◽  
Martensite Phase ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Deformation Characteristics ◽  
Dp Steels

The authors simulated the industrially used continuous annealing conditions to process dual phase (DP) steels by using a custom designed annealing simulator. Sixty-seven percentage of cold rolled steel sheets was subjected to different processing routes, including the conventional continuous annealing line (CAL), intercritical annealing (ICA), and thermal cycling (TC), to investigate the effect of change in volume fraction, shape, and spatial distribution of martensite on tensile deformation characteristics of DP steels. Annealing parameters were derived using commercial software, including thermo-calc, jmat-pro, and dictra. Through selection of appropriate process parameters, the authors found out possibilities of significantly altering the volume fraction, morphology, and grain size distribution of martensite phase. These constituent variations showed a strong influence on tensile properties of DP steels. It was observed that TC route modified the martensite morphology from the typical lath type to in-grain globular/oblong type and significantly reduced the martensite grain size. This route improved the strength–ductility combination from 590 MPa–33% (obtained through CAL route) to 660 MPa–30%. Finally, the underlying mechanisms of crack initiation/void formation, etc., in different DP microstructures were discussed.

Influence of Continuous Annealing Conditions on the Microstructure and Mechanical Properties of a C-Mn Dual Phase Steel

2010 ◽  
Vol 638-642 ◽  
pp. 3479-3484 ◽  
Author(s):  
Roberta O. Rocha ◽  
Tulio M.F. Melo ◽  
Dagoberto Brandao Santos
Keyword(s):  
Mechanical Properties ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Recrystallization Temperature ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Heating Rates ◽  
Microstructure And Mechanical Properties ◽  
Annealing Cycle ◽  
Soaking Temperature

The influence of continuous annealing variables on the microstructure and mechanical properties of a C-Mn Dual Phase (DP) steel was studied. The annealing cycles were simulated using a Gleeble machine. Some specimens were quenched at different stages of the annealing cycle in order to evaluate the microstructural evolution during the annealing process. Tensile tests and microstrutural analysis were carried out. The results showed that high heating rates increased the final recrystallization temperature and as a consequence the microstructure obtained was refined. Austenite grain nucleation and growth were also influenced by the heating rates. Soaking temperature was the most influent variable on the mechanical properties, i. e., the yield strength increased and the tensile strength decreased with an increase in the soaking temperature. Microstructural analysis showed that not only martensite, but also bainite and martensite-retained autenite constituent (MA) were formed. Undissolved carbides were also detected by transmission electron microscopy.

Effect of Different Coiling Temperature on Mechanical Properties in Hot Rolled TRIP Steel

2011 ◽  
Vol 239-242 ◽  
pp. 1092-1095
Author(s):  
Xu Tao Gao ◽  
Ai Min Zhao ◽  
Zheng Zhi Zhao ◽  
Ming Ming Zhang ◽  
Di Tang
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
X Ray Diffraction ◽  
Coiling Temperature ◽  
Experimental Steel ◽  
Transformation Induced Plasticity ◽  
X Ray ◽  
Trip Steels ◽  
Hot Rolled ◽  
Scanning Electron

By means of optical microscopy(OM), scanning electron microscopy(SEM),X-ray diffraction(XRD),And tensile test, Mechanical Properties of hot rolled transformation -induced plasticity (TRIP) steels which were prepared through three different coiling temperature was investigated. Result reveals that the formability index of the experimental steel descends when the coiling temperature becomes low. Different coiling temperature has greater impact on retained austenite. Amount and carbon content of retained austenite in the experimental steel get less with lower coiling temperature.

Microstructure Optimization in δ-TRIP Steels with Al and Nb

2018 ◽  
Vol 930 ◽  
pp. 501-506
Author(s):  
Eustáquio de Souza Baêta Júnior ◽  
Ramón Alves Botelho ◽  
Leonardo Sales Araújo ◽  
Luiz P. Brandão ◽  
Sergio Neves Monteiro
Keyword(s):  
Chemical Composition ◽  
Alloying Elements ◽  
Eutectoid Temperature ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Plasticity Effect ◽  
Δ Ferrite ◽  
Areas Of Interest ◽  
Thermocalc Software ◽  
Strength And Ductility

δ-TRIP steel is a recent concept and has been developed over the last ten years aiming to combine good mechanical strength and ductility. This class of steels is multiphase and contains δ and α ferrites, as well as austenite, bainite and/or martensite. The TRIP (Transformation Induced Plasticity) effect is influenced by those phases proportion, which depends on alloying contents. This paper investigates a chemical composition that allows adequate proportion among the phases, optimizing the microstructures by means of computational methods. These microstructures are designed to contain between 10 to 50% austenite, 10 to 70% α-ferrite and 20 to 80% δ-ferrite at the eutectoid temperature. The ThermoCalc Software [1] was used to predict the fractions of the microconstituents, producing graphs describing areas of interest of microconstituents as function of alloying elements variations that leads to the desired microstructure. Results indicate that the designed volume of the phases can be found for certain proportions among the alloying elements, higher concentrations of Al and Nb combined with C allow or not the occurrence of carbides and other phases in smaller quantities.

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