Super-high-strength and formable medium Mn steel manufactured by warm rolling process

Hu, Bin; He, Binbin; Cheng, Guan-Ju; Yen, Hung‐Wei; Huang, Mingxin; Luo, Haiwen

doi:10.1016/j.actamat.2019.05.043

Cited by 129 publications

(50 citation statements)

References 57 publications

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“…Furthermore, the formation of precipitates is considered to be responsible for the suppression of the complete dislocation annihilation during annealing and hence increasing the yield strength via the dislocation hardening effect. In the same context for V-alloyed MMn steel, Hu et al [38] reported a small increment in yield strength due to grain refinement, however, they emphasized the role of VC precipitates and dislocation hardening in increasing the yield strength. The observed increase in yield strength due to V alloying is in agreement with several studies [39][40][41][42] that reported solely the pronounced effect of V precipitates; however, the current study emphasizes additional effects, such as grain-boundary, solid-solution, and dislocation strengthening.…”

Section: Interplay Among Different Strengthening Effects Induced By Vmentioning

confidence: 97%

Development of a Cr-Ni-V-N Medium Manganese Steel with Balanced Mechanical and Corrosion Properties

Allam

Guo

Sevsek

et al. 2019

Metals

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A novel medium manganese (MMn) steel with additions of Cr (18%), Ni (5%), V (1%), and N (0.3%) was developed in order to provide an enhanced corrosion resistance along with a superior strength–ductility balance. The laboratory melted ingots were hot rolled, cold rolled, and finally annealed at 1000 °C for 3 min. The recrystallized single-phase austenitic microstructure consisted of ultrafine grains (~1.3 µm) with a substantial amount of Cr- and V-based precipitates in a bimodal particle size distribution (100–400 nm and <20 nm). The properties of the newly developed austenitic MMn steel X20CrNiMnVN18-5-10 were compared with the standard austenitic stainless steel X5CrNi18-8 and with the austenitic twinning-induced plasticity (TWIP) steel X60MnAl17-1. With a total elongation of 45%, the MMn steel showed an increase in yield strength by 300 MPa and in tensile strength by 150 MPa in comparison to both benchmark steels. No deformation twins were observed even after fracture for the MMn steel, which emphasizes the role of the grain size and precipitation-induced change in the austenite stability in controlling the deformation mechanism. The potentio-dynamic polarization measurements in 5% NaCl revealed a very low current density value of 7.2 × 10−4 mA/cm2 compared to that of TWIP steel X60MnAl17-1 of 8.2 × 10−3 mA/cm2, but it was relatively higher than that of stainless steel X5CrNi18-8 of 2.0 × 10−4 mA/cm2. This work demonstrates that the enhanced mechanical properties of the developed MMn steel are tailored by maintaining an ultrafine grain microstructure with a significant amount of nanoprecipitates, while the high corrosion resistance in 5% NaCl solution is attributed to the high Cr and N contents as well as to the ultrafine grain size.

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Section: Interplay Among Different Strengthening Effects Induced By Vmentioning

confidence: 97%

Development of a Cr-Ni-V-N Medium Manganese Steel with Balanced Mechanical and Corrosion Properties

Allam

Guo

Sevsek

et al. 2019

Metals

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“…In addition, a large amount of equiaxed ferrite grains can be observed in all samples, especially in sample I-10 h (Figure 4c). Such a result may be attributed to the recrystallization behavior of ferrite during the aging process [6].…”

Section: Microstructure Of Aged Medium-mn Steelmentioning

confidence: 99%

“…Austenite and ferrite + austenite microstructures are considered the optimal candidates for developing a cold-rolled 1.3 GPa-grade sheet due to the occurrence of transformationinduced plasticity (TRIP), twinning-induced plasticity (TWIP), and microband-induced plasticity (MBIP), respectively [5][6][7][8][9][10]. TWIP steels show ideal UTS (>1.0 GPa) and TE (>60%), but offer poor YS (0.2-0.6 GPa) due to austenite matrix characteristics [10].…”

Section: Introductionmentioning

confidence: 99%

“…In ferrite + austenite duplex steels, the sustainable transformation from austenite to martensite during tensile testing greatly contributes to their excellent mechanical properties. To further optimize the mechanical properties, grain refinement strengthening [10] and precipitation strengthening [6,7] have been employed to improve the YS. Through these methods, strength is significantly enhanced, but the ductility is greatly limited.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Mechanical Properties of a Medium-Mn Steel with 1.3 GPa-Strength and 40%-Ductility

et al. 2021

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Steel designs with superior mechanical properties have been urgently needed in automotive industries to achieve energy conservation, increase safety, and decrease weight. In this study, the aging process is employed to enhance the yield strength (YS) by tailoring the distribution of V-rich precipitates and to improve ductility by producing high volume fractions of recrystallized ferrite in cold-rolled medium-Mn steel. A reliable method to acquire ultra-high strength (1.0–1.5 GPa), together with ductility (>40%), is proposed via utilizing non-recrystallized austenite and recrystallized ferrite. Similarly to conventional medium-Mn steels, the TRIP effect, along with the mild TWIP effect, is responsible for the main deformation mechanisms during tensile testing. However, the coupled influence of precipitation strengthening, grain refinement strengthening, and dislocation strengthening contributes to an increase in YS. The studied steel, aged at 650 °C for 5 h, demonstrates a YS of 1078 MPa, ultimate tensile strength (UTS) of 1438 MPa, and tensile elongation (TE) of 30%. The studied steel aged at 650 °C for 10 h shows a UTS of 1306 MPa and TE of 42%, resulting in the best product in terms of of UTS and TE, at 55 GPa·%. Such a value surpasses that of the previously reported medium-Mn steels containing equal mass fractions of various microalloying elements.

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“…Medium-Mn steel (MMnS) is a third-generation automotive steel with excellent strength and plasticity. With the increasing requirement for lightweight and safety in the automotive industry, MMnS has become a promising steel in the manufacturing industry [17,18]. However, the researches were mainly focused on micro-structure and on mechanical properties in tensile tests involved no speed combinations [19,20,21].…”

Section: Introductionmentioning

confidence: 99%

Effects of Servo Tensile Test Parameters on Mechanical Properties of Medium-Mn Steel

Chi

Han

2019

Materials

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As a new type of third-generation automotive steel with high strength and plasticity, medium-Mn steel (MMnS) has been widely used in automotive industries for its excellent properties. In recent years, servo stamping technology for high-strength metal forming is a hot topic due to its good performance in forming under complex processing conditions, and servo parameters determine the forming quality. In this paper, experiments considering tensile speed and position where speed changes (PSC) were carried out on MMnS to investigate the influences of tensile parameters on mechanical properties including strength and total elongation (TE). The results show that PSC does not significantly impact total elongation. Initial tensile speed (ITS) and final tensile speed (FTS) significantly impact the total elongation. The interaction between all tensile parameters can impact total elongation. Two artificial neural networks, back propagation neural network (BPNN) and radial basis function neural network (RBFNN), were used to establish analytical models. The results of supplemental experiment and residual analysis were conducted to verify the accuracy of the analytical models. The BPNN has a better performance and the analytical model shows that with the increase of PSC, it has a slight impact on the changes of optimal and minimum total elongation, but the combinations of tensile parameters to obtain total elongations higher than 40% change significantly.

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Super-high-strength and formable medium Mn steel manufactured by warm rolling process

Cited by 129 publications

References 57 publications

Development of a Cr-Ni-V-N Medium Manganese Steel with Balanced Mechanical and Corrosion Properties

Development of a Cr-Ni-V-N Medium Manganese Steel with Balanced Mechanical and Corrosion Properties

Microstructure and Mechanical Properties of a Medium-Mn Steel with 1.3 GPa-Strength and 40%-Ductility

Effects of Servo Tensile Test Parameters on Mechanical Properties of Medium-Mn Steel

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