Formation of a Nanostructure in a Low-carbon Steel Under High Current Density Electropulsing

2002 ◽  
Vol 17 (5) ◽  
pp. 921-924 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Manling Sui ◽  
Douxing Li ◽  
Guanhu He ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Current Density ◽  
High Current Density ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
High Current ◽  
Low Carbon ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Electropulsing Treatment

The microstructure of a low-carbon steel after high current density electropulsing treatment was characterized by high-resolution transmission electron microscopy. It was found that nanostructured γ-Fe could be formed in the coarse-grained steel after the electropulsing treatment. The mechanism of the formation of a nanostructure was discussed. It was thought that change of the thermodynamic barrier during phase transformation under electropulsing was a factor that cannot be neglected. It was reasonable to anticipate that a new method might be developed to produce nanostructured materials directly from the conventional coarse-grained crystalline materials by applying high current density electropulsing.

Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

2000 ◽  
Vol 15 (10) ◽  
pp. 2065-2068 ◽  
Author(s):  
W. Zhang ◽  
M. L. Sui ◽  
K. Y. Hu ◽  
D. X. Li ◽  
X. N. Guo ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Coarse Grained ◽  
High Current ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Before And After ◽  
Electropulsing Treatment ◽  
Zn Alloy

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

Effects of Al, Si and N Content on the Formation of M-A Constituent and HAZ Toughness of Ti-Containing Low-Carbon Steel

2021 ◽  
Vol 1016 ◽  
pp. 42-49
Author(s):  
Kook Soo Bang ◽  
Joo Hyeon Cha ◽  
Kyu Tae Han ◽  
Hong Chul Jeong
Keyword(s):  
Carbon Steel ◽  
Impact Toughness ◽  
Low Carbon Steel ◽  
Charpy Impact ◽  
Coarse Grained ◽  
Low Carbon ◽  
N Content ◽  
Si Content ◽  
The Impact ◽  
Haz Toughness

The present work investigated the effects of Al, Si, and N content on the impact toughness of the coarse-grained heat-affected zone (CGHAZ) of Ti-containing low-carbon steel. Simulated CGHAZ of differing Al, Si, and N contents were prepared, and Charpy impact toughness was determined. The results were interpreted in terms of microstructure, especially martensite-austenite (M-A) constituent. All elements accelerated ferrite transformation in CGHAZ but at the same time increased the amount of M-A constituent, thereby deteriorating CGHAZ toughness. It is believed that Al, Si, and free N that is uncombined with Ti retard the decomposition of austenite into pearlite and increase the carbon content in the last transforming austenite, thus increasing the amount of M-A constituent. Regardless of the amount of ferrite in CGHAZ, its toughness decreased linearly with an increase of M-A constituent in this experiment, indicating that HAZ toughness is predominantly affected by the presence of M-A constituent. When a comparison of the effectiveness is made between Al and Si, it showed that a decrease in Si content is more effective in reducing M-A constituents.

scholarly journals Relationship Between Bake Hardening, Snoek-Köster and Dislocation-Enhanced Snoek Peaks in Coarse Grained Low Carbon Steel

2016 ◽  
Vol 61 (3) ◽  
pp. 1723-1732 ◽  
Author(s):  
Weijuan Li ◽  
Shengshi Zhao ◽  
Hengyi Zhang ◽  
Xiaolong Jin
Keyword(s):  
Carbon Steel ◽  
Internal Friction ◽  
Dislocation Structure ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
Low Carbon ◽  
Bake Hardening ◽  
Maximum Value ◽  
Solute Carbon ◽  
Further Development

AbstractIn the present work, specimens prepared from coarse grained low carbon steel with different prestrains were baked and then, their bake hardening (BH) property and internal friction were determined. TEM was used to characterize the dislocation structure in BH treated samples. The measurements of internal friction in prestrained samples and baked samples were carried out using a multifunctional internal friction apparatus. The results indicate that, in coarse grained low carbon steel, the bake hardening properties (BH values) were negative, which were increased by increasing the prestrain from 2 to 5%, and then were decreased by increasing the prestrain from 5 to 10%. In the specimen with prestrain 5%, the BH value reached the maximum value and the height of Snoek-Köster peak was observed to be the maximum alike. With increasing the prestrain, both of the BH value and Snoek-Köster peak heights are similarly varied. It is concluded that Snoek-Köster and dislocation-enhanced Snoek peaks, caused by the interactions between interstitial solute carbon atoms and dislocations, can be used in further development of the bake hardening steels.

scholarly journals The Variation Effect of Electric Current Toward Tensile Strength on Low Carbon Steel Welding with Electrode E7018

Teknomekanik ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 9-16
Author(s):  
Muhammad Agung Pratomo ◽  
Jasman Jasman ◽  
Nelvi Erizon ◽  
Yolli Fernanda
Keyword(s):  
Tensile Strength ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
High Current ◽  
Low Carbon ◽  
Polarity Determination ◽  
Good Penetration ◽  
Electric Polarity ◽  
Selection Of

The strength of the welding result is strongly influenced by several factors, one of which is the selection of high current. This study aims to determine the effect of high current of welding on the strength of low carbon steel welding joints. The process of welding the material uses the open V seam connection type. The variations of the high current used were 80 A, 100 A and 130 A. The specimen used was a carbon steel plate with code of 1.0038 with thickness of 8 mm and the electrode used was the E7018 electrode with diameter of 3.2 mm. The strength of the welding results is influenced by arc voltage, amount of current, welding speed, amount of penetration and electric polarity. Determination of the amount of current in metal joints using arc welding affects the work efficiency and welding materials. Based on the research, it was found that welding using high current of 100 ampere produced the highest tensile strength value of all test specimens that were given welding treatment and good penetration results.

FEM Simulation of Influence of Asymmetric Cold Rolling on Through-Thickness Strain Gradient in Low-Carbon Steel Sheets

2018 ◽  
Vol 385 ◽  
pp. 455-460
Author(s):  
Denis Pustovoytov ◽  
Alexander Pesin ◽  
Alexander P. Zhilyaev ◽  
Georgy I. Raab
Keyword(s):  
Carbon Steel ◽  
Process Parameters ◽  
Strain Gradient ◽  
Low Carbon Steel ◽  
Sheet Thickness ◽  
Coarse Grained ◽  
Metallic Materials ◽  
Low Carbon ◽  
Influence Of Process Parameters ◽  
Single Pass

Grain refinement by severe plastic deformation can make conventional metallic materials several times stronger, but it leads to dramatic loss of their ductility. Gradient structure through the thickness of processed material represents a new strategy for producing a superior combination of high strength and good ductility. In gradient metallic materials the grain size increases gradually from nanoscale at the surface to coarse-grained in the core. Strain gradient can be considered as a mechanism of creating of such microstructures. Providing of predetermined strain gradient in the metallic materials can be achieved by asymmetric rolling (AR), when circumferential speeds of the top and bottom work rolls are different. Since the AR is a continuous process, it has great potential for industrial production of large-scaled sheets. Searching the optimal process parameters which can provide special strain gradients through sheet thickness is very important. This paper presents the distributions of the effective strain through sheet thickness of low-carbon steel AISI 1015 processed by a single-pass AR. Influence of process parameters was investigated by the finite element method with using software DEFORM 2D. Extremely high strain gradient e ≈ 4...8 through sheet thickness during a single-pass AR was found. FE analysis of the deformation characteristics, presented in this study, can be used for optimization of the AR process as a method of fabrication of metallic materials with gradient microstructures.

Changes in Mechanical and Microstructural Properties of Magnesium Alloys Resulting from Superimposed High Current Density Pulses

2021 ◽  
Vol 1016 ◽  
pp. 385-391
Author(s):  
Eugen Demler ◽  
Alexander Diedrich ◽  
Andrej Dalinger ◽  
Gregory Gerstein ◽  
Sebastian Herbst ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Current Density ◽  
High Current Density ◽  
Sheet Material ◽  
Compressive Load ◽  
Underlying Mechanism ◽  
Coarse Grained ◽  
High Current ◽  
Mechanical And Microstructural Properties ◽  
The Impact

Magnesium alloys are important engineering materials due to their good combination of strength and very low densities. However, the low ductility imposed by the hcp-lattice has thus far limited the application of magnesium alloys as sheet material. The use of the electroplastic effect offers a route to increase formability of magnesium alloys while being more energy efficient than conventional hot forming. The underlying mechanism (s) of this effect have not yet been fully understood. This study investigates the impact of high current density electrical pulses on magnesium alloys. Special consideration was given to the effect of the orientation of the applied electric current relative to the mechanical loading of the specimens. The results show that the mechanical properties of coarse-grained materials are more strongly affected by the current pulses than finer grained material. Applying the current parallel to the compressive load shows a more pronounced softening of the material than pulses applied perpendicular to the mechanical stress. Microstructure investigations revealed the formation of twinning solely in the interior of grains even at stresses below the yield point for both configurations.

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