Non-metallic inclusions in electroslag remelting: a review

Shi, Chengbin; Wang, Shijun; Li, Jing; Cho, Jung‐Wook

doi:10.1007/s42243-021-00700-4

Cited by 24 publications

(6 citation statements)

References 105 publications

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“…Thereby it must be taken into consideration that NMI dissolution or absorption into the slag, as pointed out in refs. [34,35], are considered to be the two main mechanisms for the removal of NMI. Using low or no CaF 2 -containing slags, which according to Milles and Keene [36] possess high viscosities, not only changes the flow behavior, but may therefore also affect the absorption process of NMI toward lower efficiency.…”

Section: Discussionmentioning

confidence: 99%

Effect of the Slag Composition on the Process Behavior, Energy Consumption, and Nonmetallic Inclusions during Electroslag Remelting

Schneider

Wiesinger

Gelder

et al. 2022

steel research int.

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Electroslag remelting (ESR) is a well-established secondary refining process for many steels and Ni-base alloys with highest requirements regarding material properties. The main purposes are a dense solidification of ingots with a low degree of segregation as well as the reduction of medium-sized and especially complete removal of large nonmetallic inclusions (NMI). The specific energy consumption of ESR is documented in the range from 880 to over 2000 kWh t À1 . [1][2][3][4][5][6][7] Rising requirements regarding sustainability, emission control, and environmental protection have triggered new awareness for this topic. [4,8,9] Besides plant geometry and design, the customarily CaF 2 -based slag plays the key role in the heat generation and energy consumption of ESR. Key properties are the melting point as well as the electrical and thermal conductivity. [2,10] Other factors such as fill ratio and the amount of slag, or the melt rate can also have a strong effect. [4,8,[11][12][13][14][15][16] According to Holzgruber, [16] rising fill ratios up to 0.4 lead to a reduction in specific energy consumption due to a better heat transfer into the electrode and less radiation losses at the free slag surface. A further increase in fill ratio surprisingly resulted in a reversed trend due to changing immersion depths. Results from Li et al., [14] both laboratory scale and industrial size, demonstrate the strong effects of fill ratio (0.24 and 0.6) and electrical conductivity on the specific energy consumption with values below 1000 kWh t À1 at higher fill ratios combined with low or no CaF 2 -containing slags. CaF 2 -free slags in Brückmann and Schwerdtfeger [17] confirmed their particular advantage in specific energy consumption with values below 1000 kWh t À1 .There are only few reports of systematic research on energy consumption in ESR on the industrial scale. A recent investigation with a wider variation of slags is documented in refs. [5][6][7], and confirms an almost linear increase with electrical conductivity. A similar but less pronounced increase is reported in Jäger and Kühnelt [18] for slag composition with a wide variety of CaF 2 contents and a significantly higher fill ratio. A recent summary on the different effects of the fill ratio and the electrical conductivity on the specific energy consumption can be found in Schneider et al., [4] indicating that the energy consumption data from laboratory scale

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Section: Discussionmentioning

confidence: 99%

Effect of the Slag Composition on the Process Behavior, Energy Consumption, and Nonmetallic Inclusions during Electroslag Remelting

Schneider

Wiesinger

Gelder

et al. 2022

steel research int.

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“…During the ESR process, new inclusions are also formed apart from the pre-existing inclusions that remain. Figure 5 a shows the formation of non-metallic inclusions and the process of inclusion removal during ESR [ 86 ]. Stages Ⅰ, Ⅱ, and Ⅲ are oxidized inclusions generated inside the molten steel and stage Ⅳ entails new non-metallic inclusions generated during the solidification of molten steel.…”

Section: Development In Microstructure Manipulation and Strengthening...mentioning

confidence: 99%

“… ( a ) Schematic illustration of inclusion removal and fresh inclusion generation during the ESR process [ 86 ]. Morphology of carbides in different ESR ingots: ( b ) 600 A; 0 mT, ( c ) 600 A; and 50 mT.…”

Section: Development In Microstructure Manipulation and Strengthening...mentioning

confidence: 99%

Development Trend in Composition Optimization, Microstructure Manipulation, and Strengthening Methods of Die Steels under Lightweight and Integrated Die Casting

Bao,

Yang,

Dong

et al. 2023

Materials

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In the general environment of lightweight automobiles, the integrated die-casting technology proposed by Tesla has become the general mode to better achieve weight reduction in automobiles. The die-casting mold required by integrated die-casting technology has the characteristics of large scale and complexity. Hence, higher requirements are put forward for the comprehensive performance of the die steel. Despite the stagnation in the progress of conventional strengthening methods, enhancing the performance of die steel has become increasingly challenging. Indeed, it necessitates exploring novel die steel and optimizing heat treatment and reinforcement technologies. This article summarizes and analyzes the development status of die steel and corresponding heat treatment and microstructure manipulation as well as strengthening methods and elaborates on an excellent nano-strengthening technology. Furthermore, this review will aid researchers in establishing a comprehensive understanding of the development status of die steel and the processes utilized for its strengthening. It will also assist them in developing die steel with improved comprehensive performance to meet the high demand for mold steel in the integrated die-casting technology of the new era.

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“…After PESR, the proportion of small-size inclusions less than 1.5 μm increased, and the proportion of inclusions larger than 2 μm decreased. The reason is that, first, some inclusions (especially large-size ones) can be absorbed by the slag pool during the aggregation of liquid melting film to form droplets at the electrode tip, the droplets falling through the slag, and the interaction between the liquid slag and the molten steel [36][37][38] ; second, due to the rapid solidification rate of molten steel, the polymerization and growth of inclusions are inhibited. [39,40] However, considering the removal of large-size inclusions after PESR, the average size of inclusion decreased from 1.34 to 1.25 μm.…”

Section: Inclusion Evolution In 30cr15mo1n Steel During Pim-pesr Dupl...mentioning

confidence: 99%

A Promising Pressurized Duplex Manufacturing Route of High Nitrogen Stainless Steel

Feng

Xia

et al. 2022

steel research int.

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By comparing the advantages and disadvantages of the existing single‐step pressurized metallurgical manufacturing technologies of high nitrogen stainless steel (HNS), a promising pressurized duplex manufacturing route, i.e., pressurized induction melting (PIM) and pressurized electroslag remelting (PESR), is proposed. The PIM stage mainly carries on the nitrogen alloying, deoxidation and desulfurization, and the PESR process mainly takes responsibility for further desulfurization, removal of large‐size inclusion, and elevating solidification quality. During PIM, the deoxidation is achieved by vacuum carbon deoxidation combined with magnesium and rare‐earth compound treatment. Subsequently, the PESR is conducted under high nitrogen pressure without adding nitrided ferroalloys. To precisely control the nitrogen content and avoid segregation and escape of nitrogen, the three‐stage nitrogen pressure collocation is developed. The high nitrogen stainless bearing steel 30Cr15Mo1N (DIN 1.4108) is manufactured as an example by the duplex route, and a PIM–PESR ingot with high nitrogen content, high cleanliness, fine and dispersive inclusions, and compact solidification structure is obtained. Moreover, the steel possesses a homogeneous microstructure, slightly better mechanical properties, and corrosion resistance compared with that manufactured by the single‐step PESR process. Finally, a pressurized ladle refining and PESR duplex route are proposed for large‐scale industrial production of HNSs.

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Non-metallic inclusions in electroslag remelting: a review

Cited by 24 publications

References 105 publications

Effect of the Slag Composition on the Process Behavior, Energy Consumption, and Nonmetallic Inclusions during Electroslag Remelting

Effect of the Slag Composition on the Process Behavior, Energy Consumption, and Nonmetallic Inclusions during Electroslag Remelting

Development Trend in Composition Optimization, Microstructure Manipulation, and Strengthening Methods of Die Steels under Lightweight and Integrated Die Casting

A Promising Pressurized Duplex Manufacturing Route of High Nitrogen Stainless Steel

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