Understanding Hot vs. Cold Rolled Medium Manganese Steel Deformation Behavior Using In Situ Microscopic Digital Image Correlation

2018 ◽  
Vol 941 ◽  
pp. 198-205 ◽  
Author(s):  
Aniruddha Dutta ◽  
Dirk Ponge ◽  
Stefanie Sandlöbes ◽  
Dierk Raabe
Keyword(s):  
Image Correlation ◽  
Manganese Steel ◽  
Tempered Martensite ◽  
Spatial Alignment ◽  
Medium Manganese Steel ◽  
Reverted Austenite ◽  
Cold Rolled ◽  
Fresh Martensite ◽  
Hot Rolled ◽  
Continuous Yielding

We address the differences in yield stresses between hot and cold rolled medium manganese steel showing continuous yielding. Continuous yielding in both, the hot and cold rolled samples were resulting from reverted austenite islands plastically deforming first and less strain in the tempered martensite matrix. At higher global strains, strain was taken up not only by the reverted austenite, but also by tempered martensite and fresh martensite formed from the austenite through martensitic phase transformation during deformation. Strain localization was also observed in the hot rolled samples. This localization is caused by cumulative deformation of colonies of lamellar reverted austenite islands. It is interpreted in terms of the spatial alignment of austenite colonies to the loading direction in addition to the crystallographic orientation.

Microstructure Evolution and Mechanical Properties of 67GPa•% Grade Medium Manganese Steel

2021 ◽  
Vol 1035 ◽  
pp. 404-409
Author(s):  
Zhe Rui Zhang ◽  
Ren Bo Song ◽  
Nai Peng Zhou ◽  
Wei Feng Huo
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Annealing Temperature ◽  
High Strength ◽  
Total Elongation ◽  
Manganese Steel ◽  
Experimental Steel ◽  
Medium Manganese Steel ◽  
Hot Rolled ◽  
Hot Rolled Steel

In this study, a new Fe-6Mn-4Al-0.4C high strength medium manganese hot rolled steel sheet was designed. The influence mechanism of the intercritical annealing (IA) temperature on microstructure evolution and mechanical properties of experimental steel were studied by SEM and XRD. The experimental steel was held for 30 minutes at 640°C, 680°C, 720°C, 760°C, 800°C, respectively. When the annealing temperature was 640°C, cementite particles precipitated between the austenite and ferrite phase boundary. As the annealing temperature increased, the cementite gradually dissolved and disappeared, the fraction of lamellar austenite increased significantly. When the annealing temperature is 800°C, the coarse equiaxed austenite and ferrite appeared. The yield strength (YS) decreased, the product of strength and elongation (PSE) and total elongation (TE) both increased first and then decreased, while the ultimate tensile strength (UTS) showed the opposite trend. The experimental steel exhibited excellent comprehensive mechanical properties after held at 760°C for 30 min. The UTS was 870 MPa, the YS was 703 MPa, and the TE was 77 %, the PSE was 67 GPa·%.

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

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 2 ◽  
Author(s):  
Barbara Grzegorczyk ◽  
Aleksandra Kozłowska ◽  
Mateusz Morawiec ◽  
Rafał Muszyński ◽  
Adam Grajcar
Keyword(s):  
Deformation Temperature ◽  
Tensile Deformation ◽  
Plastic Instability ◽  
Manganese Steel ◽  
Experimental Investigations ◽  
Medium Manganese Steel ◽  
Medium Mn Steel ◽  
Lower Strain ◽  
Chatelier Effect ◽  
Hot Rolled

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.

Impact and Rolling Abrasive Wear Behavior and Hardening Mechanism for Hot-Rolled Medium-Manganese Steel

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Jian Wang ◽  
Qingliang Wang ◽  
Xiao Zhang ◽  
Dekun Zhang
Keyword(s):  
Wear Resistance ◽  
Martensitic Transformation ◽  
Work Hardening ◽  
Wear Behavior ◽  
Manganese Steel ◽  
High Manganese ◽  
High Manganese Steel ◽  
Medium Manganese Steel ◽  
Dislocation Strengthening ◽  
Hot Rolled

The coupled impact and rolling wear behavior of the medium-manganese austenitic steel (Mn8) were studied by comparison with the traditional Hadfield (Mn13) steel. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), and transmission electron microscope (TEM) were used to analyze the wear and hardening mechanisms. The experimental results show that the impact and rolling wear resistance of hot-rolled medium-manganese steel (Mn8) is better than that of high-manganese steel (Mn13) under conditions of low-impact load. The better work hardening sensitivity effectively improves the wear resistance of medium-manganese steel. Not only the coefficient of friction is low, but the mass loss and wear rate of the wear are lower than that of high-manganese steel. After impact and rolling wear, a hardened layer with a thickness of about 600 μm is formed on the wear surface. The highest microhardness of the subsurface layer for Mn8 is about 594 HV and the corresponding Rockwell hardness is about 55 HRC, showing the remarkable work hardening effect. The wear-resistant strengthening mechanism of medium-manganese steel is compound strengthening, including the deformation-induced martensitic transformation, dislocation strengthening, and twin strengthening. In initial stages of impact and rolling abrasion, dislocation strengthening plays a major role. When the deformation reaches a certain extent, the deformation-induced martensitic transformation and twinning strengthening begin to play a leading role.

Strain Rate Dependent Mechanical Stability of Retained Austenite in Hot-Rolled Medium-Mn Sheet Steels

2021 ◽  
Vol 1016 ◽  
pp. 946-951
Author(s):  
Mateusz Morawiec ◽  
Adam Grajcar
Keyword(s):  
Strain Rate ◽  
Mechanical Stability ◽  
Total Elongation ◽  
Manganese Steel ◽  
Strain Rates ◽  
Sheet Steels ◽  
Rate Dependent ◽  
Medium Manganese Steel ◽  
Dynamic Tensile Test ◽  
Hot Rolled

The paper presents microstructural and mechanical results of medium manganese steel deformed under high strain rates. The rotary hammer tests at strain rates of 250, 500 and 1000 s-1 were applied. Mechanical properties under dynamic tensile loads were determined. According to the obtained results, when strain rate increased the yield point of the steel increased. An opposite trend was present regarding total elongation. In case of tensile strength, its level is similar for all analyzed deformation rates. The microstructure of the steel after the dynamic tensile test is composed of bainite, martensite and martensitic-austenitic islands. The strain-induced martensitic transformation was identified in microscopic investigations.

scholarly journals Microstructure Evolution and Tensile Behaviour of a Cold Rolled 8 Wt Pct Mn Medium Manganese Steel

2021 ◽  
Author(s):  
T. W. J. Kwok ◽  
P. Gong ◽  
X. Xu ◽  
J. Nutter ◽  
W. M. Rainforth ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Intercritical Annealing ◽  
Tensile Tests ◽  
Rolling Reduction ◽  
Manganese Steel ◽  
Tensile Behaviour ◽  
Significant Drop ◽  
Cold Rolling Reduction ◽  
Medium Manganese Steel ◽  
Cold Rolled

AbstractA novel medium manganese steel with composition Fe–8.3Mn–3.8Al–1.8Si–0.5C–0.06V–0.05Sn was developed and thermomechanically processed through hot rolling and intercritical annealing. The steel possessed a yield strength of 1 GPa, tensile strength of 1.13 GPa and ductility of 41 pct. In order to study the effect of cold rolling after intercritical annealing on subsequent tensile properties, the steel was further cold rolled up to 20 pct reduction. After cold rolling, it was observed that the strain hardening rate increased continuously with increasing cold rolling reduction but without a significant drop in ductility during subsequent tensile tests. The microstructural evolution with cold rolling reduction was analysed to understand the mechanisms behind this phenomena. It was found that cold rolling activated additional twinning systems which provided a large number of potent nucleation sites for strain induced martensite to form during subsequent tensile tests in what can be described as an enhanced TRIP effect.

Formation of an Ultrafine-Grained Austenite-Containing Microstructure from a Cold-Rolled Medium-Manganese Steel Processed Using Intercritical Annealing

2013 ◽  
Vol 762 ◽  
pp. 31-37 ◽  
Author(s):  
Han Dong ◽  
Wen Quan Cao ◽  
Jie Shi
Keyword(s):  
Volume Fraction ◽  
Intercritical Annealing ◽  
Grain Structure ◽  
Manganese Steel ◽  
High Angle ◽  
Annealing Behavior ◽  
Misorientation Distribution ◽  
Ultrafine Grained ◽  
Medium Manganese Steel ◽  
Cold Rolled

The behavior of 60% cold-rolled medium-manganese steel (0.1C5Mn) during intercritical annealing, has been examined using various techniques. Microstructural observations showed a slight coarsening of the subgrain/grain structure during intercritical annealing, without any apparent change in the misorientation distribution. In addition, the formation of ultrafine austenite grains took place mainly at high-angle boundaries and rarely at low angle boundaries, suggesting a heterogeneous austenite nucleation process in this steel. The results indicated that the annealing behavior of cold rolled medium manganese steels is controlled by the extensive recovery of the ferrite phase and formation of austenite phase with an austenite volume fraction of ~20%. It was proposed that the segregation of manganese and carbon to high-angle boundaries promoted austenite nucleation and growth, as such segregation decreases the Gibbs energy of austenite.

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