Microstructures and Mechanical Properties of 7Mn Steel Manufactured by Different Rolling Processes

Hu, Bin; Luo, Haiwen

doi:10.3390/met7110464

Cited by 17 publications

(17 citation statements)

References 27 publications

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“…In this case, the morphology of cold-rolled medium-Mn steels is similar to that of hot-rolled medium-Mn steels [36][37][38][39][40][41]. It was most likely due to the sluggish recovery and recrystallization at the low annealing temperature.…”

Section: Influence Of Intercritical Annealing Temperature On Microstrmentioning

confidence: 68%

“…When the intercritical annealing temperature was further increased, ferrite and austenite were fully recrystallized, showing equiaxed morphology (Figure 10d), which was generally obtained in cold-rolled medium-Mn steels in the literature [8,15,37,40,41,53]. This equiaxed morphology in cold-rolled medium-Mn steels was explained by the recrystallization.…”

Section: Influence Of Intercritical Annealing Temperature On Microstrmentioning

confidence: 71%

“…It was reported that the hot-rolled or austenitized medium-Mn steels exhibit an elongated morphology after intercritical annealing [8,[36][37][38][39][40][41], inheriting the morphology of martensite. In contrast, the cold-rolled medium-Mn steels usually manifest an equiaxed grain morphology after intercritical annealing [8,37,[40][41][42][43]. It seems that the cold rolling prior to the intercritical annealing provides a driving force for recrystallization, which significantly affects the microstructural morphology of medium-Mn steels.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Intercritical Annealing Temperature on Microstructure and Mechanical Properties of a Cold-Rolled Medium-Mn Steel

Song

Zhou

et al. 2018

Metals

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Medium-Mn steels are characterized by ultrafine-grained (UFG) duplex microstructure consisting of ferrite and a large amount of retained austenite. Intercritical annealing is of great importance to achieving the UFG duplex microstructure and adjusting amount as well as stability of retained austenite. In the present work, the influence of intercritical annealing temperature on the microstructure and mechanical properties was investigated in a cold-rolled medium-Mn steel Fe-12Mn-3Al-0.05C. Particularly, the dependence of microstructural morphology on intercritical annealing temperature was emphasized to reveal the genesis of the microstructural morphology in medium-Mn steels. The ferrite-austenite duplex microstructure manifested an elongated morphology in the specimen annealed at 555 • C, which inherited the lath structure of the cold-rolled state. The medium-Mn steel exhibited a continuous yielding behavior and a relatively low strain-hardening rate. With an increase in intercritical annealing temperature up to 650 • C, the amount of retained austenite increased and microstructure was partially recrystallized, showing a mixture of elongated and equiaxed grain morphologies. When the intercritical annealing was applied at 700 • C, the medium-Mn steel mainly exhibited recrystallized microstructure with equiaxed morphology. The optimal balance between the amount and the stability of retained austenite led to an enhancement of strain hardening and ductility. With a further increase in the intercritical annealing temperature to 750 • C, the medium-Mn steel possessed pronounced strain-hardening behavior at the beginning of the tensile deformation with deteriorated ductility.

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Section: Influence Of Intercritical Annealing Temperature On Microstrmentioning

confidence: 68%

Section: Influence Of Intercritical Annealing Temperature On Microstrmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Intercritical Annealing Temperature on Microstructure and Mechanical Properties of a Cold-Rolled Medium-Mn Steel

Song

Zhou

et al. 2018

Metals

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“…That is why the PLC effect is so pronounced in TWIP steels. However, recent studies proved that it also takes place in medium-Mn steels [15,24,25]. This process usually takes place in a range of specific temperatures and strain rates.…”

Section: Discussionmentioning

confidence: 99%

“…TWIP steels in the last decades have displayed important delayed cracking, which was industrially solved by decreasing the C content, Al alloying, and/or metallurgical processing [22,23]. Medium Mn steels have a less pronounced problem of delayed cracking compared to high-Mn steels [24,25].The PLC effect is commonly known as characteristic serrations which can be observed on a strain-stress curve during a tensile test. The PLC effect has not been fully characterized yet.…”

mentioning

confidence: 99%

Effect of Deformation Temperature on the Portevin-Le Chatelier Effect in Medium-Mn Steel

Grzegorczyk

Kozłowska

Morawiec

et al. 2018

Metals

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Experimental investigations of the plastic instability phenomenon in a hot-rolled medium manganese steel were performed. The effects of tensile deformation in a temperature range of 20-140 • C on the microstructure, mechanical properties, and flow stress serrations were analyzed. The Portevin-Le Chatelier (PLC) phenomenon was observed for the specimens deformed at 60 • C, 100 • C, and 140 • C. It was found that the deformation temperature substantially affects the type and intensity of serrations. The type of serration was changed at different deformation temperatures. The phenomenon was not observed at room temperature. The plastic instability occurring for the steel deformed at 60 • C was detected for lower strain levels than for the specimens deformed at 100 • C and 140 • C. The increase of the deformation temperature to 100 • C and 140 • C results in shifting the PLC effect to a post uniform deformation range. The complex issues related to the interaction of work hardening, the transformation induced plasticity (TRIP) effect, and the PLC effect stimulated by the deformation temperature were addressed. stabilize the retained austenite through its carbon enrichment [8]. An alternative approach is to apply thermomechanical processing (TMP) as direct one-step cooling following the hot rolling. The TMP has the potential for energy savings and high productivity due to the elimination of the need for successive heating [9][10][11]. Chemical composition and processing parameters are designed to obtain the optimal TRIP (Transformation Induced Plasticity) effect, which ensures superior mechanical properties [12,13].Besides the many advantages of this group of steels, some problems during their processing can occur. Medium manganese steels [14-17] and high manganese steels [18][19][20] are prone to plastic instabilities phenomena associated with a serrated flow behavior-Portevin-Le Chatelier (PLC) effect and the appearance of Lüders bands. This is especially the case for cold-rolled steel sheets [21]. Moreover, it critically depends on the carbon level. With a higher C content, a pronounced effect is more visible. The heterogeneous deformation related to the increase in flow stress can lead to numerous cracks during the forming of sheets. Moreover, delayed cracking after deep drawing can appear. Delayed cracking is mostly observed in high-Mn content steels of the high austenite volume fraction. With the increased volume fraction of (retained) austenite, hydrogen embrittlement may be a more important concern. TWIP steels in the last decades have displayed important delayed cracking, which was industrially solved by decreasing the C content, Al alloying, and/or metallurgical processing [22,23]. Medium Mn steels have a less pronounced problem of delayed cracking compared to high-Mn steels [24,25].The PLC effect is commonly known as characteristic serrations which can be observed on a strain-stress curve during a tensile test. The PLC effect has not been fully characterized yet. However, some correlations between the TRIP a...

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Influence of microstructure on the hydrogen diffusion behavior in dual-phase steels: an electrochemical permeation study

Reddy

Govindaraj²,

Neelakantan³

2022

J Mater Sci

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Microstructures and Mechanical Properties of 7Mn Steel Manufactured by Different Rolling Processes

Cited by 17 publications

References 27 publications

Influence of Intercritical Annealing Temperature on Microstructure and Mechanical Properties of a Cold-Rolled Medium-Mn Steel

Influence of Intercritical Annealing Temperature on Microstructure and Mechanical Properties of a Cold-Rolled Medium-Mn Steel

Effect of Deformation Temperature on the Portevin-Le Chatelier Effect in Medium-Mn Steel

Influence of microstructure on the hydrogen diffusion behavior in dual-phase steels: an electrochemical permeation study

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