Study on the Mechanical Stability of Retained Austenite in Cold-Rolled Medium-Mn Steel

2014 ◽  
Vol 936 ◽  
pp. 1283-1289
Author(s):  
Jun Hu ◽  
Wen Quan Cao ◽  
Jie Shi ◽  
Han Dong
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Residual Austenite ◽  
Tensile Tests ◽  
Medium Mn Steel ◽  
Cold Rolled ◽  
Mn Steel ◽  
High Mechanical Stability

The mechanical stability of the retained austenite in the cold-rolled medium-Mn steel was studied. Tensile tests were carried out to measure the mechanical properties of the annealed steel. Scanning electron microscopy was applied to characterize the microstructure evolution during the tensile process; X-ray diffraction analysis was used to determine the residual austenite content in the deformed steel. It was found that the volume fraction of retained austenite gradually decreases with strain .The value of the stability coefficient of retained austenite k was small in the test steel, which indicated high mechanical stability of retained austenite. Due to TRIP effect, the high mechanical stability of the retained austenite strongly delays the onset of necking, which resulted in good comprehensive mechanical properties with ultrahigh strength and plasticity.

Effect of Al on the Microstructure and Mechanical Properties of Hot-Rolled Medium-Mn Steel

2018 ◽  
Vol 941 ◽  
pp. 292-298 ◽  
Author(s):  
Ding Ting Han ◽  
Yun Bo Xu ◽  
Ying Zou ◽  
Zhi Ping Hu ◽  
Shu Qing Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Trip Steel ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Microstructure And Mechanical Properties ◽  
Medium Mn Steel ◽  
Hot Rolled ◽  
Mn Steel

The present investigation was made to study the effect of Al on the microstructure and mechanical properties of hot-rolled medium-Mn TRIP steel (abbreviated as Al-TRIP). As a contrast, a Si-added medium-Mn TRIP steel (abbreviated as Si-TRIP) was also studied. Addition Al in medium-Mn steel can raise Ac3 temperature, which will restrain austenite transformation and expand the two-phase region, promoting Mn and C elements enriched in austenite. In-depth microstructure and mechanical properties analysis were carried out for the hot-rolled Al-TRIP and Si-TRIP steels in this study. The microstructure was characterized by scanning electron microscope (SEM) and electron probe microanalyzer (EPMA). Volume fraction of retained austenite was measured by D/max2400 X-ray diffractometer (XRD). A dual-phase microstructure consisting of ultra-fine grained intercritical ferrite (IF) and lath-like retained austenite (RA) with high mechanical stability was obtained after annealing at 630°C for 2h for Al-TRIP steel. As prolonging the intercritical annealing time, the stability of RA decreased primarily due to the increase of grain size. The tensile test results indicated that the Al-TRIP steel possessed a better combination of tensile strength and elongation compared to Si-TRIP steel. Excellent mechanical properties with yield strength of 790MPa, tensile strength of 1050MPa, total elongation of 35% and UTS×TEL of 39GPa·% was obtained for the Al-TRIP steel.

scholarly journals A Novel Cyclic-Quenching-ART for Stabilizing Austenite in Nb–Mo Micro-Alloyed Medium-Mn Steel

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1090 ◽  
Author(s):  
Chunquan Liu ◽  
Qichun Peng ◽  
Zhengliang Xue ◽  
Chengwei Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Total Elongation ◽  
Practical Significance ◽  
Strengthening Effect ◽  
Medium Mn Steel ◽  
Cyclic Quenching ◽  
Mn Steel

In the context of obtaining an excellent elongation and tensile-strength combination in the third generation of advanced high strength steel, we emphasized the practical significance of adjusting the retained austenite fraction and stability in medium-Mn steel to obtain better mechanical properties. A novel cyclic quenching and austenite reverse transformation (CQ-ART) was used to obtain a large retained austenite content in Fe-0.25C-3.98Mn-1.22Al-0.20Si-0.19Mo-0.03Nb (wt.%) Nb–Mo micro-alloyed medium-Mn steel. The results show that after twice cyclic quenching and ART, the alloy exhibited optimum comprehensive properties, characterized by an ultimate tensile strength of 838 MPa, a total elongation of 90.8%, a product of strength and elongation of 76.1 GPa%, and the volume fraction of austenite of approximately 62 vol.%. The stability of retained austenite was significantly improved with the increasing of the number of cyclic quenching. Moreover, the effects of CQ-ART on the microstructure evolution, mechanical properties, C/Mn partitioning behavior, and austenite stability were investigated. Further, the strengthening effect of microalloying elements Nb–Mo was also discussed.

scholarly journals Quasi-Situ Characterization of Retained Austenite Orientation in Quenching and Partitioning Steel via Uniaxial Tensile Tests

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4609
Author(s):  
Pengfei Gao ◽  
Jie Liu ◽  
Weijian Chen ◽  
Feng Li ◽  
Jingyu Pang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Early Stage ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Quenching And Partitioning ◽  
Austenite Grains

As a representative of the third generation of advanced high strength steel, the quenching and partitioning steel has excellent potential in automobile manufacturing. The characterization and analysis of the mechanical properties and microstructure of the quenching and partitioning steel during deformation is an effective way to explore the microstructure evolution and transformation-induced plasticity effects of complex phase steels. The relationship between the microstructure morphology and mechanical properties of a 1180 MPa-grade quenching and partitioning steel was investigated through interrupted uniaxial tensile tests plus quasi-situ electron backscatter diffraction measurements. A mixture of ferrite, martensite, and retained austenite was observed in the microstructure. It was found that the volume fraction of global retained austenite decreased linearly with the increase of displacement (0 mm–1.05 mm). The evolution of the retained austenite with typical crystal direction ranges with deformation was characterized. Results show that the orientation (111) and (311) account for the highest proportion of retained austenite grains in the undeformed sample and the mechanical stability of the (311) retained austenite grains is the best. Moreover, the retained austenite grains rotated significantly in the early stage of the specimen deformation process (around yielding), and the work hardening of the specimen was weak at this stage, simultaneously.

Effect of volume fraction and mechanical stability of austenite on ductility of medium Mn steel

2019 ◽  
Vol 26 (11) ◽  
pp. 1209-1218 ◽  
Author(s):  
Si-lian Chen ◽  
Zhao-xi Cao ◽  
Chang Wang ◽  
Chong-xiang Huang ◽  
Dirk Ponge ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Volume Fraction ◽  
Medium Mn Steel ◽  
Mn Steel

scholarly journals Influence of Microstructural Morphology on Hydrogen Embrittlement in a Medium-Mn Steel Fe-12Mn-3Al-0.05C

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 929 ◽  
Author(s):  
Xiao Shen ◽  
Wenwen Song ◽  
Simon Sevsek ◽  
Yan Ma ◽  
Claas Hüter ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
The Other ◽  
Duplex Microstructure ◽  
Ultrafine Grained ◽  
Medium Mn Steel ◽  
Microstructural Morphology ◽  
Cold Rolled ◽  
Mixed Microstructure ◽  
Mn Steel

The ultrafine-grained (UFG) duplex microstructure of medium-Mn steel consists of a considerable amount of austenite and ferrite/martensite, achieving an extraordinary balance of mechanical properties and alloying cost. In the present work, two heat treatment routes were performed on a cold-rolled medium-Mn steel Fe-12Mn-3Al-0.05C (wt.%) to achieve comparable mechanical properties with different microstructural morphologies. One heat treatment was merely austenite-reverted-transformation (ART) annealing and the other one was a successive combination of austenitization (AUS) and ART annealing. The distinct responses to hydrogen ingression were characterized and discussed. The UFG martensite colonies produced by the AUS + ART process were found to be detrimental to ductility regardless of the amount of hydrogen, which is likely attributed to the reduced lattice bonding strength according to the H-enhanced decohesion (HEDE) mechanism. With an increase in the hydrogen amount, the mixed microstructure (granular + lamellar) in the ART specimen revealed a clear embrittlement transition with the possible contribution of HEDE and H-enhanced localized plasticity (HELP) mechanisms.

scholarly journals Effects of the austenitizing temperature on the mechanical properties of cold-rolled medium-Mn steel system

2017 ◽  
Vol 691 ◽  
pp. 51-59 ◽  
Author(s):  
Z.Z. Zhao ◽  
J.H. Liang ◽  
A.M. Zhao ◽  
J.T. Liang ◽  
D. Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Austenitizing Temperature ◽  
Medium Mn Steel ◽  
Cold Rolled ◽  
Mn Steel

Study on Microstructures and Mechanical Properties of Cold-Rolled C-Mn-Si-Al TRIP Steel

2010 ◽  
Vol 146-147 ◽  
pp. 678-681
Author(s):  
Zheng You Tang ◽  
Hua Ding
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Total Elongation ◽  
Partial Substitution ◽  
Cold Rolled ◽  
Microstructures And Mechanical Properties

The effect of the partial substitution of Si by Al on the microstructures and the mechanical properties of cold rolled C-Mn-Si TRIP steel was investigated. The results show that the partial substitution of Si by Al could refine the microstructures, increase the volume fraction of ferrite and retained austenite. In addition, the excellent mechanical properties of the Al partial substituted TRIP steel could be obtained, the tensile strength, total elongation and strength-ductility of C-Mn-Si-Al TRIP steel are 739MPa, 38% and 28082MPa%, respectively.

scholarly journals Microstructure Evolution and Mechanical Stability of Retained Austenite in Medium-Mn Steel Deformed at Different Temperatures

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3042 ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Adam Grajcar
Keyword(s):  
Microstructure Evolution ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Thermomechanical Processing ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Medium Mn Steel ◽  
Different Temperatures ◽  
Static Tensile ◽  
Xrd Techniques

The temperature-dependent microstructure evolution and corresponding mechanical stability of retained austenite in medium-Mn transformation induced plasticity (TRIP) 0.17C-3.1Mn-1.6Al type steel obtained by thermomechanical processing was investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques. Specimens were deformed up to rupture in static tensile tests in the temperature range 20–200 °C. It was found that an increase in deformation temperature resulted in the reduced intensity of TRIP effect due to the higher stability of retained austenite. The kinetics of strain-induced martensitic transformation was affected by the carbon content of retained austenite (RA), its morphology, and localization in the microstructure.

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