Temperature and Stress State Influence on Mechanical Properties and Damage Evolution of Dual-Phase Steels

2014 ◽  
Vol 783-786 ◽  
pp. 886-891
Author(s):  
Mayerling Martinez ◽  
Jerôme Chottin ◽  
Eric Hug
Keyword(s):  
Mechanical Properties ◽  
Automotive Industry ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Transmission Electron ◽  
Structural Applications ◽  
Microstructure Parameters ◽  
Evolution Of Microstructure

Dual Phase steels are increasingly selected for structural applications including parts in automotive industry because of their interesting mechanical properties and their good formability. This work presents an experimental analysis of the evolution of microstructure of a DP1000 alloy submitted to thermomechanical loadings. Monotonous tensile tests were performed at various plastic strain levels up to fracture for temperatures ranging between 25 °C and 440 °C. A strong degradation of the mechanical properties is observed for temperatures higher than 275 °C. The evolution with plastic strains and temperature of the microstructure was studied by scanning and transmission electron microscopy. Different microstructure parameters such as volume fraction of martensite and carbide precipitation were taken into account in order to understand the mechanical behavior of DP1000 steels tested in this temperature range. The microstructural observations indicate that diminution of carbon in martensite, due to its diffusion to form carbides, could partially explain the drop in mechanical properties at around 275 °C.

Multiscale Material Modeling and Simulation of the Mechanical Behavior of Dual Phase Steels Under Different Strain Rates: Parametric Study and Optimization

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Tarek M. Belgasam ◽  
Hussein M. Zbib
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dual Phase ◽  
Strain Rates ◽  
Microstructure Parameters ◽  
Dp Steels

Recent studies on developing dual phase (DP) steels showed that the combination of strength/ductility could be significantly improved when changing the volume fraction and grain size of phases in the microstructure depending on microstructure properties. Consequently, DP steel manufacturers are interested in predicting microstructure properties as well as optimizing microstructure design at different strain rate conditions. In this work, a microstructure-based approach using a multiscale material and structure model was developed. The approach examined the mechanical behavior of DP steels using virtual tensile tests with a full micro-macro multiscale material model to identify specific mechanical properties. Microstructures with varied ferrite grain sizes, martensite volume fractions, and carbon content in DP steels were also studied. The influence of these microscopic parameters at different strain rates on the mechanical properties of DP steels was examined numerically using a full micro-macro multiscale finite element method. An elasto-viscoplastic constitutive model and a response surface methodology (RSM) were used to determine the optimum microstructure parameters for a required combination of strength/ductility at different strain rates. The results from the numerical simulations were compared with experimental results found in the literature. The developed methodology proved to be a powerful tool for studying the effect and interaction of key strain rate sensitivity and microstructure parameters on mechanical behavior and thus can be used to identify optimum microstructural conditions at different strain rates.

scholarly journals Characterization of Nanobainitic Structure Obtained in 100Crmnsi6-4 Steel after Industrial Heat Treatment/ Charakteryzacja Struktury Nanobainitycznej Wytworzonej W Handlowej Stali Łożyskowej – 100Crmnsi6-4 W Przemysłowej Obróbce Cieplnej

2014 ◽  
Vol 59 (4) ◽  
pp. 1637-1640 ◽  
Author(s):  
J. Dworecka ◽  
E. Jezierska ◽  
K. Rozniatowski ◽  
W. Swiatnicki
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Tensile Tests ◽  
Bearing Steel ◽  
Transformation Kinetics ◽  
Transmission Electron ◽  
Microstructure Parameters ◽  
Static Tensile

Abstract The aim of the work was to produce a nanobainitic structure in the commercial bearing steel - 100CrMnSi6-4 and to characterize its structure and mechanical properties. In order to produce this structure the austempering heat treatment was performed, with parameters that have been selected on the basis of dilatometric measurements of phase transformation kinetics in steel. The heat treatment process was performed in laboratory as well as in industrial furnaces. The obtained structure was characterized using transmission electron microscopy. In order to investigate the effect of the microstructure parameters on the material’s mechanical properties, the hardness, impact strength and static tensile tests have been conducted.

scholarly journals Estimation of Strength Properties from Microhardness Results in Dual Phase Steels with Different Martensite Volume Fraction

2018 ◽  
Vol 47 (3) ◽  
pp. 206-212 ◽  
Author(s):  
Gábor Béres ◽  
Zoltán Weltsch
Keyword(s):  
Volume Fraction ◽  
Tensile Tests ◽  
Strength Properties ◽  
Indentation Load ◽  
Experimental Investigations ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Martensite Volume Fraction ◽  
Martensite Content ◽  
Hardness Values

This study is about the effect of the martensite volume fraction and indentation load on microhardness profiles of dissimilar types Dual Phase steels and DC04 mild steel. Experimental investigations were performed by mickrovickers method with using of eight different indentation loads from 0.01 kp up to 1 kp. Besides, microscope and tensile tests were carried out to complete the estimation.The hardness profiles show similar characteristics in case of all examined steels independent from the microstructure. In the lowest load ranges at 0.01 and 0.025 kp (HV0.01 and HV0.025), there are no appropriate approximations with the martensite volume fraction, due to the high deviation of the hardness results which caused by the little indentation geometry. In higher ranges, above 0.05 kp (HV0.05), linear evaluations could be applicable. With the utilization of the fitted parameters, a definite relationship is reported in the hardness values and even in the strength and elongation properties with the martensite content. Based on these correlations such contexts are added which make contact between microhardness and strength values for the practice. The discrepancy between the measured and calculated results stay under 10 HV which is less than 5%.

scholarly journals Microstructural and Mechanical Characterization of Shielded Metal Arc Welded Dual Phase Steel Joints

2020 ◽  
Vol 44 (6) ◽  
pp. 381-386
Author(s):  
Walid Laroui ◽  
Redouane Chegroune ◽  
Şükrü Talaş ◽  
Mourad Keddam ◽  
Riad Badji
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
Volume Fraction ◽  
Plain Carbon Steel ◽  
Welding Parameters ◽  
Dual Phase ◽  
Shielded Metal Arc Welding ◽  
Dual Phase Steels ◽  
Quenching Temperature ◽  
Metal Arc Welding

Dual Phase steels are widely used in industry for various reasons for their improved mechanical properties owing to their ferrite and martensite contents in microstructure and good formability at industrial scale to achieve final shape with good ductility. In this study, shielded metal arc welding experiments were performed in order to evaluate the metallurgically and mechanically the properties of Dual Phase steels obtained from plain carbon steel AISI 1010 by water quenching at intercritical temperatures. Martensite volume fraction (MVF) was related to the intercritical quenching temperature which defines the mechanical properties of Dual Phase steel. All the welding parameters were kept constant in order to get a value of heat input equals 1.37 KJ/mm for all weldments. Martensite was found to be predominated in the fusion zone and its hardness was the highest compared to base metal (BM) and heat affected zone (HAZ). The extent of ductile zone was found to be dependent on the MVF and reached over 1.2 mm wide. Tensile properties of weldments were deteriorated by 35% in ultimate tensile strength (UTS) and by 15% in elongation. The failure of all the welded joints was occurred in the SC zone, with the fractured surfaces of a dimple feature.

Microstructural Characterization of Dual and Multiphase Steels Applied to Automotive Industry

2014 ◽  
Vol 775-776 ◽  
pp. 146-150 ◽  
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.

Effect of Annealing on the Microstructure Evolution and Mechanical Properties of Dual Phase Steel

2014 ◽  
Vol 782 ◽  
pp. 111-116 ◽  
Author(s):  
Martin Šebek ◽  
Peter Horňak ◽  
Peter Zimovčák
Keyword(s):  
Mechanical Properties ◽  
Present Article ◽  
Microstructure Evolution ◽  
Dual Phase Steel ◽  
Peak Load ◽  
Tensile Tests ◽  
Dual Phase ◽  
Heat Treated ◽  
Intercritical Region ◽  
Evolution Of Microstructure

The aim of present article was to consider the influence of annealing parameters on evolution of microstructure and mechanical properties of dual phase steel. Dual phase steel was annealed according to the three chosen cycles of annealing: into intercritical region (780°C), into austenite region (920°C) and into austenite region (920°C) by subsequently cooling into intercritical region (780°C) with the hold at the temperature of 495°C. Tensile tests of the heat-treated specimens were carried out. The obtained microstructure consists from three phases: ferritic matrix, austenite and martensite. Nanoindentation experiments were performed with the peak load of 19.62 mN for ferrite grains and 0.981 mN for austenite and martensite grains, using a Berkovich tip as an indenter. The nanohardness for ferrite and martensite was 2.5 ±1 GPa and 7.1 ±1 GPa and for austenite the nanohardness varied from 4.1 to 4.5 GPa.

Mechanical behavior of high impact polystyrene based on SB copolymers as a function of synthesis conditions: Part II

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Ramón Díaz de León ◽  
Graciela Morales ◽  
Pablo Acuña ◽  
Florentino Soriano
Keyword(s):  
Mechanical Properties ◽  
Yield Stress ◽  
Volume Fraction ◽  
Interparticle Distance ◽  
Tensile Tests ◽  
High Impact ◽  
Synthesis Conditions ◽  
High Impact Polystyrene ◽  
Transmission Electron ◽  
Rubber Phase

AbstractThe mechanical properties of different high impact polystyrene (HIPS) were determined by means of impact and tensile tests. Impact strength (IS), yield stress (σy) and Young’s modulus (E) were evaluated as a function of the rubber phase morphological features such as type and particle size (Dp), volume fraction (Φ) and interparticle distance (IPD). In order to evaluate the changes produced in the rubber phase, the initiator, chain transfer agent (CTA), and type and concentration of SB copolymer were varied during the synthesis of HIPS. Transmission electron microscopy was used to analyze the materials’ morphology and the data obtained reveal that the Dp and Φ increases mainly with an increase in the PB content and/or with the use of CTA and decreases with an increase in initiator concentration. In addition, E and yield stress diminishes when increasing the dimensions of the rubber phase (Dp and Φ), contrary to the IS. The IPD/Dp ratio also indicates the dependency of the mechanical properties with respect to the rubber phase features. An increase in IPD/Dp provokes an increases in E and σy, whereas IS diminishes.

Prediction of Ferrite-Martensite Dual-Phase Steels Mechanical Properties by Use of Artificial Neural Networks

2013 ◽  
Vol 773-774 ◽  
pp. 268-274
Author(s):  
Amir Ghiami ◽  
Ramin Khamedi
Keyword(s):  
Mechanical Properties ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Back Propagation ◽  
Total Elongation ◽  
Ultimate Tensile Stress ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Good Ability ◽  
Artificial Neural

This paper presents an investigation of the capabilities of artificial neural networks (ANN) in predicting some mechanical properties of Ferrite-Martensite dual-phase steels applicable for different industries like auto-making. Using ANNs instead of different destructive and non-destructive tests to determine the material properties, reduces costs and reduces the need for special testing facilities. Networks were trained with use of a back propagation (BP) error algorithm. In order to provide data for training the ANNs, mechanical properties, inter-critical annealing temperature and information about the microstructures of many specimens were examined. After the ANNs were trained, the four parameters of yield stress, ultimate tensile stress, total elongation and the work hardening exponent were simulated. Finally a comparison of the predicted and experimental values indicates that the results obtained from the given input data reveal a good ability of the well-trained ANN to predict the described mechanical properties.

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