Deformation Behavior and Microstructure of Low Carbon High Manganese Steels in Tensile Strain

The mechanical properties of two high manganese steels with manganese contents (15% and 25%) were investigated during tensile tests at room temperature. The results indicated that the strengths of steels were a little low and the elongations were improved greatly with increasing the manganese content. Stress fluctuations were found during tensile tests of the Fe-15Mn steels, and as the strain increased the range of stress fluctuations became wider. The strain hardening exponent n of samples changed with strain in a parabola model. The microstructures before and after deformation were investigated and the results showed that phase transformation of γ (fcc) →ε (hcp) and γ (fcc) →ε (hcp) →α (bcc) induced plasticity occurred in the Fe-15Mn steels. However, in the Fe-25Mn steels, at the beginning stage of the deformation, phase transformation induced plasticity played an important role, and with the increase of deformation, the main mechanism was twinning induced plasticity.

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Mechanical Properties and Microstructural Aspects of Two High-Manganese Steels with TWIP/TRIP Effects: A Comparative Study

Metals ◽

10.3390/met11010024 ◽

2020 ◽

Vol 11 (1) ◽

pp. 24

Author(s):

Matías Bordone ◽

Juan Perez-Ipiña ◽

Raúl Bolmaro ◽

Alfredo Artigas ◽

Alberto Monsalve

Keyword(s):

Mechanical Response ◽

Volume Fraction ◽

Tensile Tests ◽

Optical Microscope ◽

Chemical Compositions ◽

High Manganese ◽

Microstructural Changes ◽

Ε Martensite ◽

High Manganese Steels ◽

Manganese Steels

This article is focused on the mechanical behavior and its relationship with the microstructural changes observed in two high-manganese steels presenting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP), namely Steel B and Steel C, respectively. Chemical compositions were similar in manganese, but carbon content of Steel B approximately doubles Steel C, which directly impacted on the stacking fault energy (SFE), microstructure and mechanical response of each alloy. Characterization of as-cast condition by optical microscope revealed a fully austenitic microstructure in Steel B and a mixed microstructure in Steel C consisting of austenite grains and thermal-induced (εt) martensite platelets. Same phases were observed after the thermo-mechanical treatment and tensile tests, corroborated by means of X-Ray Diffraction (XRD), which confirms no phase transformation in Steel B and TRIP effect in Steel C, due to the strain-induced γFCC→εHCP transformation that results in an increase in the ε-martensite volume fraction. Higher values of ultimate tensile strength, yield stress, ductility and impact toughness were obtained for Steel B. Significant microstructural changes were revealed in tensile specimens as a consequence of the operating hardening mechanisms. Scanning Electron Microscopy (SEM) observations on the tensile and impact test specimens showed differences in fracture micro-mechanisms.

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Computer-Aided Material Design for Crash Boxes Made of High Manganese Steels

Metals ◽

10.3390/met9070772 ◽

2019 ◽

Vol 9 (7) ◽

pp. 772 ◽

Cited By ~ 1

Author(s):

Angela Quadfasel ◽

Marco Teller ◽

Manjunatha Madivala ◽

Christian Haase ◽

Franz Roters ◽

...

Keyword(s):

Sheet Thickness ◽

Material Design ◽

Tensile Tests ◽

Material Strength ◽

High Manganese ◽

Material Efficiency ◽

Material Condition ◽

High Manganese Steels ◽

Material Conditions ◽

Manganese Steels

During the last decades, high manganese steels (HMnS) were considered as promising materials for crash-relevant automobile components due to their extraordinary energy absorption capability in tensile tests. However, in the case of a crash, the specific energy, absorbed by folding of a crash box, is lower for HMnS as compared to the dual phase steel DP800. This behavior is related to the fact that the crash box hardly takes advantage of the high plastic formability of a recrystallized HMnS during deformation. It was revealed that with the help of an alternative heat treatment after cold rolling, the strength of HMnS could be increased for low strains to achieve a crash behavior comparable to DP800. In this work, a multi-scale finite element simulation approach was used to analyze the crash behavior of different material conditions of an HMnS. The crash behavior was evaluated under consideration of material efficiency and passenger safety criteria to identify the ideal material condition and sheet thickness for crash absorption by folding. The proposed simulation methodology reduces the experimental time and effort for crash box design. As a result of increasing material strength, the simulation exhibits a possible weight reduction of the crash box, due to thickness reduction, up to 35%.

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Precipitation Processes in High-Manganese Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.762.405 ◽

2013 ◽

Vol 762 ◽

pp. 405-410

Author(s):

Georg Paul ◽

Kirill Khlopkov

Keyword(s):

Process Design ◽

Carbon Nitride ◽

Manganese Content ◽

Austenitic Steels ◽

High Manganese ◽

Precipitation Behaviour ◽

Carbon Manganese Steels ◽

High Manganese Steels ◽

Manganese Steels ◽

Steel Design

The highly interesting properties of high manganese steels can be further improved by microalloying. The introduction of carbon-nitride precipitates improves the yield strength and the microstructural control during the production process. Due to the high manganese content in these austenitic steels significant changes in the precipitation behaviour have to be expected in comparison to conventional carbon-manganese steels. However, although crucial for steel design, this has not been systematically described before. Preliminary results showing the effect of Nb and V are presented. Namely the softening behaviour is related to the precipitation state. In summary this allows describing the precipitation-time-temperature evolution and provides the necessary background for the alloy and process design.

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Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation—Inclusion Precipitation and Solidification Structure

ISIJ International ◽

10.2355/isijinternational.48.934 ◽

2008 ◽

Vol 48 (7) ◽

pp. 934-943 ◽

Cited By ~ 24

Author(s):

Naoki Kikuchi ◽

Seiji Nabeshima ◽

Yasuo Kishimoto ◽

Seetharaman Sridhar

Keyword(s):

Structure Refinement ◽

Solidification Structure ◽

Low Carbon ◽

Micro Structure ◽

High Manganese ◽

High Manganese Steels ◽

Manganese Steels

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Micro-structure Refinement in Low Carbon High Manganese Steels through Ti-deoxidation: Austenite Grain Growth and Decomposition

ISIJ International ◽

10.2355/isijinternational.49.1036 ◽

2009 ◽

Vol 49 (7) ◽

pp. 1036-1045 ◽

Cited By ~ 14

Author(s):

Naoki Kikuchi ◽

Seiji Nabeshima ◽

Yasuo Kishimoto ◽

Yasuhide Ishiguro ◽

Seetharaman Sridhar

Keyword(s):

Grain Growth ◽

Structure Refinement ◽

Low Carbon ◽

Micro Structure ◽

High Manganese ◽

Austenite Grain ◽

High Manganese Steels ◽

Austenite Grain Growth ◽

Manganese Steels

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Effect of Rare Earth Cerium Addition on Microstructures and Mechanical Properties of Low Carbon High Manganese Steels

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0183 ◽

2017 ◽

Vol 36 (2) ◽

pp. 145-153 ◽

Cited By ~ 4

Author(s):

M. Z. Jiang ◽

Y. C. Yu ◽

H. Li ◽

X. Ren ◽

S. B. Wang

Keyword(s):

Mechanical Properties ◽

Induction Furnace ◽

Lattice Misfit ◽

Vacuum Induction Furnace ◽

Low Carbon ◽

High Manganese ◽

Calculation Results ◽

High Manganese Steels ◽

Microstructures And Mechanical Properties ◽

Manganese Steels

AbstractLow carbon high manganese steels with different Ce contents were melted in medium frequency vacuum induction furnace. The microstructures and mechanical properties of steels were studied by OM, SEM, EDS and mechanical property testing. The results showed that the microstructures of experimental steels were refined remarkably, inclusions distributed more finely and uniformly, the tensile strength and impact toughness of tested steels both improved greatly after the addition of Ce. Thermodynamic calculation results demonstrated that Ce contained inclusions were Ce2O3 and Ce3S4, which agreed well with the results observed by SEM and EDS. By analysis of two-dimensional lattice disregistry, it was shown that the lattice misfit parameter between δ-Fe and Ce2O3, Ce3S4 are less than 6 %, which indicated that Ce2O3 and Ce3S4 could effectively act as the heterogeneous nuclei of initial δ-Fe. Therefore, the microstructures were refined significantly and the mechanical properties were improved correspondingly in Ce-added low carbon high manganese steels.

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