Application of Alkali Oxides in LF Refining Slag for Enhancing Inclusion Removal in C96V Saw Wire Steel

Inclusion removal and modification of C96V saw wire steel using Na2O- and Rb2O- containing novel low-basicity LF (ladle furnace) Refining Slags have been researched. The results indicated that the addition of Na2O deteriorates inclusion removal; by contrast, the addition of Rb2O seems to significantly enhance inclusion removal. In detail, Rb2O can improve the cleanliness in the as-quenched C96V saw wire steel melts compared to preexisting synthetic LF refining slag compositions: (i) The average inclusion diameter experienced a remarkable decrease after reaction between the liquid steel and the synthetic LF refining slag; (ii) In addition, the number of inclusions also suffered from a dramatic decrease, with the reaction time increasing from 900 to 2700 s (15 to 45 min); (iii) Furthermore, both of the MnO-SiO2-Al2O3 and CaO-SiO2-Al2O3 inclusion system mainly concentrated in the low melting zone when the composition of Rb2O in synthetic refining slag was ≥5.0 wt%. This is mainly because Na2O significantly reduces the viscosity of refining slag, while Rb2O increases it. Then, there are two remarkable influences causing the increase of viscosity of refining slag with the addition of Rb2O: the inclusions can be sufficiently entrained within the slag once absorbed due to the significant increase in the viscosity; and the slag entrapment during refining process weakened dramatically.

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Effect of Rb2O on Inclusion Removal in C96V Saw Wire Steels Using Low-Basicity LF Refining Slag

ISIJ International ◽

10.2355/isijinternational.isijint-2018-385 ◽

2018 ◽

Vol 58 (11) ◽

pp. 2032-2041 ◽

Cited By ~ 3

Author(s):

Changyong Chen ◽

Zhouhua Jiang ◽

Yang Li ◽

Meng Sun ◽

Guoqing Qin ◽

...

Keyword(s):

Refining Slag ◽

Inclusion Removal ◽

Lf Refining

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Effect of Refining Slag on the Inclusions of Hard Wire Steel during Melting Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.217-218.1174 ◽

2011 ◽

Vol 217-218 ◽

pp. 1174-1179

Author(s):

Yang Li ◽

Zhou Hua Jiang ◽

Shi You Yin ◽

Ying Zhuang ◽

Ming Li

Keyword(s):

Ternary Phase Diagram ◽

Melting Process ◽

Melting Zone ◽

Refining Slag ◽

Total Oxygen ◽

Deformation Ability ◽

Inclusion Shape ◽

Wire Steel ◽

Al2o3 Inclusion ◽

Inclusions In Steel

The effect of the refining slag composition on the total oxygen content and inclusions in steel was investigated in 100 t UHP Electric Furnace – LF – Billet CC process. The test steel was 77B hard wire steel and Si-Mn alloy was used as the deoxidizer. Three types slag were used in the industrial tests, which including CaO-CaF2, CaO-CaF2 adding CaC and CaO-Al2O3 refining slag. The results shown that the lowest total oxygen contents of rolled bar can be gained using the CaO-CaF2 refining slag adding CaC, which is 0.0036%, while the total oxygen contents of rolled bar using CaO-Al2O3 refining slag is higher a little than the heats using CaO-CaF2 refining slag. The CaO-SiO2 and CaO-Al2O3-SiO2 compound inclusions with the size of about 5 μm are the main inclusions in the heats refining by the CaO-CaF2 refining slag in the rolled bar, but the pure, indeformable Al2O3 inclusion can also be found with the size of about 10 μm. The CaO-Al2O3-SiO2 and Al2O3-SiO2-MnO compound inclusions are the main inclusions in the heats refining by the CaO-CaF2-CaC refining slag, but most of the inclusion shape is irregular with bigger size of about 10 μm. Similar with the heat using CaO-CaF2 refining slag, the pure Al2O3 inclusion with edge angle can be found in the rolled bar. The inclusions in the rolled bar treated by CaO-Al2O3 refining slag are CaO-Al2O3-SiO2 compound inclusions, most of which are nearly globular shape with the relative small size of about 5 μm. All of the inclusions in rolled bar lie on the low melting zone in the CaO-Al2O3-SiO2 ternary phase diagram in the heats using CaO-Al2O3 refining slag. The similar condition appeared on the most of the inclusions in the heats using CaO-CaF2 and CaO-CaF2 refining slag adding CaC, while part of which are lied on the high melting zone. Therefore, considering of the plastic deformation ability, the CaO-Al2O3 refining slag is the best slag for the melting process of hard wire steel.

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Hydrogen Variation in Molten Steel during LF Refining

Materials Science Forum ◽

10.4028/www.scientific.net/msf.695.353 ◽

2011 ◽

Vol 695 ◽

pp. 353-356

Author(s):

Jian Tao Ju ◽

Zhen Lin Lu ◽

Min Juan Zhang ◽

Zhao Hui Zhang ◽

Jun Yang

Keyword(s):

Molten Steel ◽

Hydrogen Content ◽

Refining Process ◽

Ladle Furnace ◽

Regular Pattern ◽

Refining Slag ◽

Feeding Speed ◽

Wire Feeding ◽

Submerged Arc ◽

Lf Refining

The hydrogen content was measured by HYDRIS hydrogen analyzer during ladle furnace (LF) refining process aiming to test the regular pattern of hydrogen variation in molten steel. The results showed that the hydrogen increased during temperature rising, Ca-treatment and soft blowing argon period, and the absolute increment were 0.64 ppm and 0.46 ppm respectively. The water in refining slag and submerged arc slag led to hydrogen increase during temperature rising period, and fast wire-feeding speed led to hydrogen increase during Ca-treatment and soft argon blowing period. In addition, during the desulfuration and alloying period, excessive large argon blowing caused the hydrogen content increasing by 0.22 ppm.

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Influence of slag-changing operation during LF refining on the inclusions in 82B high carbon steel wire

Metallurgical Research & Technology ◽

10.1051/metal/2018130 ◽

2019 ◽

Vol 116 (4) ◽

pp. 411

Author(s):

Yuxiang Dai ◽

Jing Li ◽

Chengbin Shi ◽

Wei Yan

Keyword(s):

Liquidus Temperature ◽

Early Stage ◽

Steel Wire ◽

High Carbon Steel ◽

Slag System ◽

Refining Slag ◽

High Carbon ◽

Oxide Inclusions ◽

Plant Trials ◽

Lf Refining

The influence of refining slag-changing operation on the compositions of 82B steel and inclusions were studied on the basis of plant trials combined with thermodynamic analysis. The optimized refining slag system for the refining of 82B steel was obtained through the plant experiments. The slag-changing operation had no effect on the type of oxide inclusions (CaO-SiO2-MnO-Al2O3) compared with the operation without slag-changing, whereas the CaO/SiO2 in inclusions decreased with the decrease of basicity of the top slag. The liquidus temperature of oxide inclusions were decreased with the slag-changing operation. The basicity of the refining slag should be controlled in the range of 2.5 to 3 at the early stage of LF in order to control the oxygen and sulfur in steel. At the later stage of LF refining, the basicity of refining slag should be changed to 1∼1.5, aiming to reduce the activity of [Al] in molten steel and target the good plasticity of oxide inclusions.

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