scholarly journals Future Trends on Displacive Stress and Strain Induced Transformations in Steels

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 299
Author(s):  
Adriana Eres-Castellanos ◽  
Carlos Garcia-Mateo ◽  
Francisca G. Caballero
Keyword(s):  
Mechanical Properties ◽  
Bainitic Ferrite ◽  
Stress And Strain ◽  
Future Trends ◽  
Transformation Induced Plasticity ◽  
Fundamental Knowledge ◽  
Plasticity Effect ◽  
Final Microstructure

Displacive stress and strain induced transformations are those transformations that occur when the formation of martensite or bainitic ferrite is promoted by the application of stress or strain. These transformations have been shown to be one of the mechanisms by which the mechanical properties of a microstructure can be improved, as they lead to a better ductility and strength by the transformation induced plasticity effect. This review aims to summarize the fundamental knowledge about them, both in fully austenitic or in multiphase structures, pointing out the issues that—according to the authors’ opinion—need further research. Knowing the mechanisms that govern the stress and strain induced transformation could enable to optimize the thermomechanical treatments and improve the final microstructure properties.

Microstructure and Mechanical Properties of a Lamellar-Structured Low-Alloy TRIP Steel

2021 ◽  
Vol 1016 ◽  
pp. 1188-1192
Author(s):  
Jiang Ying Meng ◽  
Zhi Geng Jia ◽  
Tong Liang Wang ◽  
Kai Fang Li ◽  
Li He Qian
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Retained Austenite ◽  
Treatment Process ◽  
Intercritical Annealing ◽  
Bainitic Ferrite ◽  
Heat Treatment Process ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Reverted Austenite

In this paper, we report a lamellar-structured low-alloy transformation-induced plasticity (TRIP) steel; the microstructure of the steel consists of alternate lamellae of intercritical ferrite and reverted austenite on microscale, with the latter consisting of bainitic ferrite laths and retained austenite films on nanoscale. Such a microstructure was produced by a heat treatment process similar to that for producing conventional TRIP-assisted steels, i.e. intercritical annealing followed by austempering. Nevertheless, quenched martensite rather than a mixture of ferrite and pearlite was used as the starting structure for intercritical annealing to form austenite, and the resulting austenite was then transformed to bainite by austempering treatment. This steel exhibits much enhanced strength-ductility combinations as compared with those conventional polygonal-structured low-alloy TRIP steels.

The Effect of Alloying Elements on Microstructure of 0,2%C TRIP Steel

2017 ◽  
Vol 891 ◽  
pp. 209-213 ◽  
Author(s):  
Ludmila Kučerová ◽  
Hana Jirková ◽  
Bohuslav Mašek
Keyword(s):  
Mechanical Properties ◽  
Reference Material ◽  
Trip Steel ◽  
Manganese Content ◽  
Mechanical Processing ◽  
Trip Effect ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
The Third ◽  
Final Microstructure

Three low alloyed transformation induced plasticity (TRIP) steels with 0.2%C were used in this work. The first one was based on the most common and popular 0.2%C - 1.5%Mn - 1.8%Si concept and was used as a reference material. The second steel was further micro-alloyed by 0.06% of Niobium. The third steel was designed with lower manganese content of 0.6% and additional alloying by 0.8% of Chromium. Thermo-mechanical processing with incorporated incremental deformation was applied to each steel. Various cooling rates and numbers of deformation steps were tested with regard to final microstructure and properties. After this optimization, microstructures with the potential to utilize TRIP effect were achieved for all steels. Very good mechanical properties were obtained with ductility typically in the interval of 30-40% and the tensile strengths in the range of 680-835 MPa.

scholarly journals Influence of Microstructure on Mechanical Properties of Bainitic Steels in Railway Applications

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 778 ◽  
Author(s):  
Omid Hajizad ◽  
Ankit Kumar ◽  
Zili Li ◽  
Roumen H. Petrov ◽  
Jilt Sietsma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Behavior ◽  
Mechanical Performance ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Uniaxial Tensile ◽  
Isothermal Heat Treatment

Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural features, such as grain size, phase fraction, as well as spatial distribution and morphology of these phases in the microstructure. To quantify the mechanical behavior of bainitic rail steels, uniaxial tensile experiments and hardness measurements were performed. In order to characterize the influence of microstructure on the mechanical behavior, various microscopy techniques, such as light optical microscopy (LOM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), were used. Three bainitic grades industrially known as B360, B1400 plus and Cr-Bainitic together with commonly used R350HT pearlitic grade were studied. Influence of isothermal bainitic heat treatment on the microstructure and mechanical properties of the bainitic grades was investigated and compared with B360, B1400 plus, Cr-Bainitic and R350HT in as-received (AR) condition from the industry. The results show that the carbide-free bainitic steel (B360) after an isothermal heat treatment offers the best mechanical performance among these steels due to a very fine, carbide-free bainitic microstructure consisting of bainitic ferrite and retained austenite laths.

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.

scholarly journals Analysis of Stress and Strain to Determine the Pressure Changes in Tight-Fitting Garment

2020 ◽  
Vol 20 (1) ◽  
pp. 49-55
Author(s):  
Nareerut Jariyapunya ◽  
Blažena Musilová
Keyword(s):  
Mechanical Properties ◽  
Mathematical Models ◽  
Initial Phase ◽  
Circumferential Stress ◽  
The Body ◽  
Stress And Strain ◽  
Laplace’S Law ◽  
Pressure Changes ◽  
The Relationship ◽  
Laplace's Law

AbstractBased on the mechanical properties of stretch fabrics and Laplace’s law, the mathematical models have been developed enabling one to determine the values of the relationship between the fabric strain and the circumferential stress depending on pressure and diameter of the body. The results obtained refer to the values of the parameters assessed for the initial phase of their exploitation, which allow us to preliminarily predict the values of these parameters.

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