钢铁研究学报(英文版)
Home
|
About Journal
|
Editorial Board
|
Instruction for Authors
|
Subscriptions
|
Advertisement
|
Contacts Us
|
Chinese
Office Online
Author Center
Peer Review
Editor Work
Office Work
Editor-in-chief
Journal Online
Forthcoming Articles
Current Issue
Archive
Read Articles
Download Articles
Email Alert
Quick Search
Advanced Search
2021 Vol. 28 No. 12
Published: 2021-12-25
1483
Cheng-bin Shi, Shi-jun Wang, Jing Li, Jung-wook Cho
Non-metallic inclusions in electroslag remelting: a review
Non-metallic inclusion in electroslag remelting is a constant topic that has been studied for decades. Different results and conclusions are obtained on some of the subjects from these previous investigations. These differences originate in part from different experimental conditions, including original inclusion chemistries in consumable electrode, slag composition, oxygen level, liquid metal compositions, deoxidation schemes, and melting rates of electroslag remelting. The advances in the operating practices of inclusion control in electroslag remelting production are reviewed. Inclusion evolution during the electroslag remelting and related processing parameters are also reviewed and assessed. The role of the reoxidation of liquid steel during electroslag remelting on oxide inclusion composition is discussed. The generation of inclusions in remelted ingot is critically assessed. Perspective and remaining issues are noted.
2021 Vol. 28 (12): 1483-1503 [
Abstract
] (
202
) [
HTML
1KB] [
PDF
0KB] (
182
)
1504
Yusuf Abba Yusuf, Wan-ming Li, Shi-shen Li, Hua-bing Li, Xi-min Zang
Effect of atmospheric pressure on physical parameters of steels and solidification conditions during PESR process: a review
The pressurized electroslag remelting (PESR) process has a remarkable impact on manufacturing high nitrogen steels, which can alter the physical parameters of steels and solidification conditions at different atmospheric pressures. The principle and applications of the PESR process are reviewed. The effect of atmospheric pressure, including Gibbs free energy, nitrogen solubility, melting point, viscosity, diffusion coefficient, partition coefficient, and nucleation rate, is explicitly expressed by empirical knowledge and quantified by thermodynamic relationships. The variation of interfacial heat transfer coefficient is discussed at different atmospheric pressures. Furthermore, the effect of atmospheric pressure on physical parameters of steels and solidification conditions during the PESR process is still in their embryonic research stage and it is important to do further study in this research field. Finally, a general concluding remark and suggestions for future development are proposed.
2021 Vol. 28 (12): 1504-1514 [
Abstract
] (
110
) [
HTML
1KB] [
PDF
0KB] (
171
)
1515
Ru Lu, Guang-qiang Li, Chang Liu, Yun-ming Gao, Yu-fei Chen, Qiang Wang
Effects of slag composition and additive type on desulfurization of rejected electrolytic manganese metal scrap by Na
2
O-containing electroslag
The recycling rate of rejected electrolytic manganese metal (EMM) scrap can be increased by inhibiting the manganese metal (MM) vaporization during the remelting process with electroslag. However, if the latter is achieved by reducing the remelting temperature, the desulfurization behavior will deteriorate. Therefore, Na
2
O-containing electroslag and metallic additive were used to increase the rejected EMM scrap recovery ratio. The respective high-temperature experiment was conducted in a MoSi
2
electrical resistance furnace filled with fluid argon at 1673 K using five different types of electroslag with the Na
2
O content ranging from 5.81% to 15.71%. High-purity metallic magnesium and magnesium calcium alloy additives were used as deoxidizers. The addition of Na
2
O and metallic additives effectively promoted the desulfurization and deoxidization of MM. The removal of sulfur and oxygen by the interaction between Na
2
O-containing electroslag melt and molten MM with metallic additive was analyzed from the thermodynamic and kinetic standpoints. The effect of Na
2
O-containing electroslag volatilization on desulfurization and deoxidization was considered. With an increase in Na
2
O content in the slag, the mass loss rates of Na
2
O and electroslag rose, as well as the final sulfur partition ratio. If the Na
2
O content volatilized in the slag melt did not exceed 10.44%, the sulfur removal ratio was increased by high sulfide capacity and CaO activity in all slags due to the addition of Na
2
O. The rejected EMM scrap deoxidization ratio grew with the increased activity of CaO and reduced activity of Al
2
O
3
in the molten slag, caused by the increased Na
2
O content in the molten slag. The addition of metallic Mg and Mg–Ca alloy indirectly promoted desulfurization and deoxidization by reducing the MnO content in the rejected EMM scrap and growing slag oxidability. The Mg–Ca alloy could also react with dissolved sulfur and oxygen, directly promoting desulfurization and deoxidization processes. The Na
2
O content in slag should not exceed 10.44% to ensure the high desulfurization and deoxidization abilities, fluidity and low volatilization of slag.
2021 Vol. 28 (12): 1515-1529 [
Abstract
] (
83
) [
HTML
1KB] [
PDF
0KB] (
198
)
1530
Yi Huang, Cheng-bin Shi, Xiu-xiu Wan, Jiang-ling Li, Ding-li Zheng, Jing Li
Effect of SiO
2
and B
2
O
3
on crystallization and structure of CaF
2
–CaO–Al
2
O
3
-based slag for electroslag remelting of ultra-supercritical rotor steel
Regarding development of the dedicated slag for electroslag remelting, crystallization characteristics of the slag exert a strong influence on the initial solidification of liquid metal in mold and surface quality of as-cast ingot. The crystallization behavior of CaF
2
–CaO–Al
2
O
3
-based slag with varying SiO
2
and B
2
O
3
contents and their correlation with the slag structure were investigated. Increasing SiO
2
(0.24–8.95 mass%) and B
2
O
3
(0–3.20 mass%) contents lowers the crystallization temperature and suppresses the crystallization of the slag melts, as well as decreases the sizes of the crystalline phases. The crystalline phases precipitated during continuous cooling of the slag melts are faceted 11CaO·7Al
2
O
3
·CaF
2
, faceted or spherical CaF
2
, and non-faceted MgO·Al
2
O
3
(or MgO) in sequence irrespective of the SiO
2
and B
2
O
3
contents of the slag. The polymerization degree of slag melts increases with increasing either SiO
2
or B
2
O
3
contents. The crystallization of the slag melts is increasingly retarded with increasing the SiO
2
and B
2
O
3
contents of the slag caused by increased component diffusion resistance originating from increased polymerization degree of the slag melts.
2021 Vol. 28 (12): 1530-1540 [
Abstract
] (
80
) [
HTML
1KB] [
PDF
0KB] (
176
)
1541
Jian-tao Ju, Kang-shuai Yang, Zhi-hong Zhu, Yue Gu, Li-zhong Chang
Effect of CaF
2
and CaO/Al
2
O
3
on viscosity and structure of TiO
2
-bearing slag for electroslag remelting
The relationship between the viscosity and structure of CaF
2
–CaO–Al
2
O
3
–MgO–TiO
2
slag with different CaF
2
contents and CaO/Al
2
O
3
ratios was studied using the rotating cylinder method, Fourier transform infrared spectroscopy, and Raman spectrometry. The activity coefficients of CaF
2
and the CaO/Al
2
O
3
ratio were determined to understand the correlation between viscosity and structure of the slag. The results suggest that the slag viscosity reduces gradually with an increase in CaF
2
content from 14.1 to 28.1 wt.% or CaO/Al
2
O
3
ratio from 0.9 to 1.5, and correspondingly apparent activation energy for viscous flow reductions. The addition of CaF
2
does not change the structure of the molten slag; however, the relaxation effect of the anionic species and the hindrance effect of the cationic species are promoted by substituting part of the non-bridging oxygens (NBO) with F
-
ions from CaF
2
, which is attributed to the formation of NBO–Ca
2+
–F
-
and NBO–Ca
2+
–NBO, respectively. However, as the CaO/Al
2
O
3
ratio increases, some of the Q
4
units in the aluminate structure are depolymerized into Q
2
units, so that the relative strength of the Al–O–Al linkage decreases, and the relative fraction of Ti
2
O
6
4-
chains increases, whereas that of O–Ti–O chains decreases slightly, resulting in depolymerization on the slag structure. Additionally, the effect of the CaO/Al
2
O
3
ratio on the structure was greater than that of CaF
2
because of the greater depolymerization effect. The variation in the activity can indirectly explain the relationship between the viscosity and structure of the aluminate structural units based on thermodynamic analysis.
2021 Vol. 28 (12): 1541-1550 [
Abstract
] (
83
) [
HTML
1KB] [
PDF
0KB] (
185
)
1551
E. Karimi-Sibaki, A. Kharicha, A. Vakhrushev, M. Wu, A. Ludwig, J. Bohacek
Investigation of effect of electrode polarity on electrochemistry and magnetohydrodynamics using tertiary current distribution in electroslag remelting process
Transport phenomena including the electromagnetic, concentration of ions, flow, and thermal fields in the electroslag remelting (ESR) process made of slag, electrode, air, mold, and melt pool are computed considering tertiary current distribution. Nernst–Planck equations are solved in the bulk of slag, and faradaic reactions are regarded at the metal–slag interface. Aiming at exploring electrochemical effects on the behavior of the ESR process, the calculated field structures are compared with those obtained using the classical ohmic approach, namely, primary current distribution whereby variations in concentrations of ions and faradaic reactions are ignored. Also, the influence of the earth magnetic field on magnetohydrodynamics in the melt pool and slag is considered. The impact of the polarity of electrode, whether positive, also known as direct current reverse polarity (DCRP), or negative, as known as direct current straight polarity (DCSP), on the transport of oxygen to the ingot of ESR is investigated. The obtained modeling results enabled us to explain the experimental observation of higher oxygen content in DCSP than that of DCRP operated ESR process.
2021 Vol. 28 (12): 1551-1561 [
Abstract
] (
99
) [
HTML
1KB] [
PDF
0KB] (
155
)
1562
Qiang Li, Zhi-bin Xia, Yi-feng Guo, Zhe Shen, Tian-xiang Zheng, Biao Ding, Yun-bo Zhong
Effect of axial static magnetic field on cleanliness and microstructure in magnetically controlled electroslag remelted bearing steel
The effect of the axial static magnetic field (ASMF) on cleanliness and microstructure in magnetically controlled elec- troslag remelted GCr15 bearing steel ingots was investigated experimentally. The results show that a magnetically con- trolled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip, resulting in thinner liquid melt film and smaller droplets. With the increase in magnetic flux density, the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF, then decreases. The cleanliness of the ingots was improved, and the count of inclusions larger than 5 μm was reduced. The microstructure of the ingots processed with a 40 mT ASMF was significantly refined. The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF. The tensile strength, impact toughness, and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved. The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.
2021 Vol. 28 (12): 1562-1573 [
Abstract
] (
77
) [
HTML
1KB] [
PDF
0KB] (
167
)
1574
Fu-bin Liu, Hai-bo Cao, Hua-bing Li, Zhou-hua Jiang, Xin Geng
Effects of current path on structure and segregation during electroslag remelting process of Inconel 718 alloy with same power input
Current-conductive mold was recently developed to extend electroslag remelting (ESR) functions to overcome some solidification defects by changing the current path. The macrostructures, microstructures, macrosegregation, and microsegregation of the Inconel 718 ingots produced by the custom laboratory-scale ESR furnace under different current paths (the classical ESR and the single power, and two circuits ESR process with current-conductive mold (ESR–STCCM)) with the same power input were compared and investigated. The results indicate that when the ingot was produced during ESR and ESR–STCCM processes, at the same power input, the pool depth was 104 and 90 mm, respectively. A flatter and shallower molten pool was obtained during ESR–STCCM process. Moreover, compared with a classical ESR ingot, the cooling rate of the centerline of ESR–STCCM ingot was increased from 12.7 to 16.7 K min
-1
. The increased cooling rates caused by decreased melting rate and thinner slag skin reduced the growth angle of columnar crystal to the vertical axis and the secondary dendrite arm spacing. Furthermore, the macrosegregation and microsegregation of segregation elements for ESR–STCCM process were dramatically reduced compared with ESR process. The average volume fraction of Laves phase was reduced from 7.39% to 6.14%, and the segregation of Nb in Laves phase was significantly reduced.
2021 Vol. 28 (12): 1574-1581 [
Abstract
] (
78
) [
HTML
1KB] [
PDF
0KB] (
160
)
1582
Yi-ru Duan, Bao-kuan Li, Xue-chi Huang, Zhong-qiu Liu
Effect of electrode change on solidification of slag and metal pool profile in electroslag remelting process
A two-dimensional axisymmetric model is established to study the effect of electrode change on the solidification of slag and metal pool profile during electroslag remelting process. The basic considerations of flow and heat transfer are included in the model, and the growth of ingot is described by the dynamic mesh technique. The electrode melting rate is predicted based on the transient thermal conductivity model between slag and electrode. The results indicate that in the electrode change stage, the slag temperature drops from 1847 to 1763 K gradually and the ‘‘hot heart’’ phenomenon is observed. And the metal pool profile is slightly changed with a depth decrease from 0.3984 to 0.3688 m. In the heating and melting stage of new electrode, the maximum slag temperature firstly increases from 1763 to 1892 K, then decreases to 1845 K, and finally at 3558 s, the maximum slag temperature is stable at 1884 K. Solidified slag shell with a maximum volume of 7.31 × 10
–3
m
3
is formed at the electrode tip, and then, the solidified slag melts completely. The depth of metal pool firstly rises to 0.3700 m and then drops to 0.3565 m. As the preheating temperature of the new electrode increases from 473 to 973 K, the maximum volume of solidified slag decreases from 0.00748 to 0.00592 m
3
, and the time from heating to melting of the new electrode decreases from 996 to 887 s.
2021 Vol. 28 (12): 1582-1590 [
Abstract
] (
73
) [
HTML
1KB] [
PDF
0KB] (
175
)
1591
Fa Ji, Rui Xu, Yu-long Gao, Qing-chao Tian, Lu Wang, Zhi-xia Xiao, Fu-xing Yin
Effect of Ti and rare earth on microsegregation and large-sized precipitates of H13 steel
Large-sized precipitates are fatal to the thermal fatigue of H13 hot work die steel. Different amounts of Ti and/or rare earth (RE) were added in H13 steel during electroslag remelting to improve the element segregation and refine the large-sized precipitates. The results show that as Ti content increases from 0.0032 to 0.057 wt.%, the segregation of Cr, Mo and V becomes more severe. V-rich M(C, N) carbides are shorter, and their branches are denser in 3D observation. Moreover, the number density of V-rich M(C, N) carbides with a size less than 2 μm increases and that with other sizes decreases. In addition, Ti-rich MN nitrides with the size greater than 4 μm increases significantly at high Ti content. When RE content increases from 0.0051 to 0.036 wt.%, the segregation of main alloying elements is first weakened and then aggravated. Compared with that in RE-free H13 steel, V-rich M(C, N) carbides are less developed in 3D observation, and the change in number density is similar to that of Ti-modified alloys. After composite modification of 0.024 wt.% Ti and 0.011 wt.% RE, the segregation of alloying element and V-rich M(C, N) carbides are not significantly improved.
2021 Vol. 28 (12): 1591-1604 [
Abstract
] (
126
) [
HTML
1KB] [
PDF
0KB] (
258
)
1605
Ding-li Zheng, Guo-jun Ma, Xiang Zhang, Meng-ke Liu, Zhi Li
Evolution of MnS and MgO·Al
2
O
3
inclusions in AISI M35 steel during electroslag remelting
Thermodynamics and kinetics of dissociation and precipitation of MnS inclusions, as well as the effect of reoxidation in liquid steel on MgO·Al
2
O
3
inclusions in AISI M35 steel during electroslag remelting (ESR) process were investigated. The inclusions found in the consumable electrode were MnS, MgO·Al
2
O
3
and MnS adhering to MgO·Al
2
O
3
. MnS inclusions were nearly spherical and ellipse in morphology, and most of them were less than 2 μm in size. MgO·Al
2
O
3
inclusions were polygonal and nearly spherical and most about 1–4 μm in size. The inclusions in ESR ingot observed by scanning electron microscopy–energy-dispersive X-ray spectrometer were polygonal and nearly spherical MgO·Al
2
O
3
. MnS inclusions in the consumable electrode were completely dissociated before the liquid film dripping into molten slag pool. The controlling step of MnS inclusions dissociation was the mass transfer of [Mn] in the liquid steel. During the solidification process, the thermodynamic driving force could not meet MnS inclusions precipitation before the solid fraction exceeds 0.996, and the kinetics condition is too poor for the growth of MnS inclusions in the steel when the solid fraction is larger than 0.996. MgO·Al
2
O
3
inclusions in ESR ingot originated from the remained MgO·Al
2
O
3
inclusions in consumable electrode and the fresh ones formed by the reaction between dissolved magnesium, oxygen and aluminum in liquid steel.
2021 Vol. 28 (12): 1605-1616 [
Abstract
] (
94
) [
HTML
1KB] [
PDF
0KB] (
199
)
1617
Jie Zhang, Jing Li, Cheng-bin Shi
Numerical analysis of role of melting rate on electroslag remelting continuous directional solidification of a die steel
The effect of melting rate on the temperature distribution, velocity field, macrosegregation and dendrite arm spacing during electroslag remelting continuous directional solidification process with a mould of 160 mm in diameter was investigated. The mechanism of solute transport and dendrite growth of austenitic hot-work die steel during electroslag remelting process was proposed. The results showed that a lower melting rate contributed to a higher temperature gradient as well as a shallower liquid metal molten pool. With the increase in the melting rate, the central counterclockwise vortex in the slag and clockwise vortex in the liquid metal molten pool grew, whereas the marginal clockwise vortex in the slag reduced. With increasing melting rate, the macrosegregation of carbon became more serious, whereas the average value of secondary dendrite arm spacing first decreased and then increased. The secondary dendrite arm spacing reached a minimum value at melting rate of 98 kg/h, which indicated that 98 kg/h was a proper melting rate for electroslag remelting continuous directional solidification process with a mould of 160 mm in diameter.
2021 Vol. 28 (12): 1617-1624 [
Abstract
] (
119
) [
HTML
1KB] [
PDF
0KB] (
178
)
1625
Cong-peng Kang, Fu-bin Liu, Huai-bei Zheng, Hua-bing Li, Zhou-hua Jiang, Kui Chen, Hao-yang Suo, Xin-hao Yu
Microstructure evolution and mechanical properties of PESR 55Cr17Mo1VN plastic die steel during quenching and tempering treatment
55Cr17Mo1VN high nitrogen martensitic stainless steel is usually applied to the high-quality mold, which is largely produced by the pressurized electro slag remelting process. The microstructure evolution of quenching and tempering heat treatment were investigated and an optimal heat treatment process to achieve excellent mechanical properties was found out. The main precipitates in the steel included carbon-rich type M
23
C
6
and nitrogen-rich type M
2
N. With increasing austenitizing temperature, the equivalent diameter of the precipitates got fined, and retained austenite content increased significantly when the austenitizing temperature exceeded 1020 °C. The fracture mode gradually changed from brittle fracture to ductile fracture with increasing tempering temperature from 200 to 550 °C. The experimental steel tempered at 350 °C achieved a good combination of hardness (60.6 HRC) and strength (2299.2 MPa) to meet service requirements. Flake M
23
C
6
precipitated along martensite lath boundaries and the secondary hardening phenomenon occurred when the tempering temperature was 450 °C. Due to the high nitrogen content, M
2
N precipitated from the inside of laths and matrix when tempered at 550 °C.
2021 Vol. 28 (12): 1625-1633 [
Abstract
] (
127
) [
HTML
1KB] [
PDF
0KB] (
187
)
钢铁研究学报(英文版)
News
·
《钢铁研究学报》第二届青年编委招募
·
Call for Papers for the Special Issue on “Corrosion and wear of materials in extreme environments”
·
Call for Papers for the Special Issue on “Resources Recycling of Solid Wastes from Ironmaking and St
·
Call for Papers for the Special Issue on "Numerical Simulation of Multiphase and Multiscale Metallur
·
Call for Papers for the Special Issue on “Application of AI in steelmaking and ferrous materials”
More
Author Center
Instruction for Authors
Template
Copyright Agreement
Links
More
Copyright © JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL
Supported by: Beijing Magtech
