Effect of TiO2addition to LF refining slag on the Ti, Al, and cleanliness of Ti-stabilized stainless steel

The morphology, composition, size, and number of inclusions in 439 ultra-pure ferritic stainless steel samples were analyzed using an automatic scanning electron microscope combined with an energy-dispersive X-ray spectrometer. In addition, the appropriate contents of titanium, aluminum, and calcium were analyzed through the coupling of thermodynamics calculation and experimental results. CaO-Al2O3-MgO inclusions existed in the 439 steel before Ti additions in the ladle furnace (LF) refining process. After Ti addition in the LF refining process, the inclusions were transformed into CaO-Al2O3-MgO-TiOx inclusions. The evolution of these inclusions was consistent with thermodynamic calculation, which indicated that when the Al, Ca, and Ti contents were within a reasonable range, Ca treatment could significantly modify the aluminate and spinel to form CaO-Al2O3-MgO liquid inclusions. In addition, the compositions of inclusions after the addition of titanium were mostly located in the Al2O3-TiOx stable phase. The collision of the CaO-Al2O3-MgO liquid inclusions and Al2O3-TiOx inclusions resulted in the modification of the CaO-Al2O3-MgO-TiOx inclusions. The compositions of most inclusions were located in the liquid zone. The control range of the aluminum, calcium, and titanium contents was obtained: logAl% ≥ 1.481logTi% − 0.7166, Ca% ≥ 34.926(Al%)3 − 3.3056(Al%)2 + 0.1112(Al%) − 0.0003.

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Process Practice of Refining for Free Cutting Austenite Stainless Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.325-326.94 ◽

2013 ◽

Vol 325-326 ◽

pp. 94-96

Author(s):

Yi Min Wang ◽

Xian Cai Wang ◽

Li Min Wen

Keyword(s):

Stainless Steel ◽

Continuous Casting ◽

Continuous Casting Machine ◽

Casting Machine ◽

Electric Arc ◽

Ladle Furnace ◽

Arc Furnace ◽

Refining Slag ◽

Austenite Stainless Steel ◽

Argon Oxygen Decarburization

FreeCutting Austenite Stainless Steel 303CuS2(%:≤0.08C,8.00~10.00Ni, 17.00~19.00Cr, 1.50~3.50Cu,0.24~0.35S) is smelted by 60t Electric Arc Furnace~60t Argon Oxygen Decarburization~60t Ladle Furnace~3 Flow continuous casting machine. With decreasing basicity of AOD refining slag from 2.0 to 1.6, controlling AOD tapping slag amount and tapping temperature, the [S] in AOD tapping steel increases to 0.008%~0.012% from original 0.004%~0.006%, after feeding S-wire containing 50% S and controlling the end temperature, the yield of S increases to 60%~70% from original 30%~50%, the qualified ratio of raises from 85% to 100%.

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Effect of Na2O and Rb2O on Inclusion Removal in C96V Saw Wire Steels Using Low-Basicity LF (Ladle Furnace) Refining Slags

Metals ◽

10.3390/met8090691 ◽

2018 ◽

Vol 8 (9) ◽

pp. 691 ◽

Cited By ~ 4

Author(s):

Changyong Chen ◽

Zhouhua Jiang ◽

Yang Li ◽

Meng Sun ◽

Kui Chen ◽

...

Keyword(s):

Melting Zone ◽

Refining Process ◽

Ladle Furnace ◽

Refining Slag ◽

Dramatic Decrease ◽

Inclusion Removal ◽

Wire Steel ◽

Al2o3 Inclusion ◽

Lf Refining ◽

Slag Entrapment

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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Oxide-Inclusion Evolution in the Steelmaking Process of 304L Stainless Steel for Nuclear Power

Metals ◽

10.3390/met9020257 ◽

2019 ◽

Vol 9 (2) ◽

pp. 257 ◽

Cited By ~ 1

Author(s):

Xingrun Chen ◽

Guoguang Cheng ◽

Yuyang Hou ◽

Jingyu Li

Keyword(s):

Stainless Steel ◽

Continuous Casting ◽

Nuclear Power ◽

Oxide Inclusion ◽

Electric Arc ◽

304L Stainless Steel ◽

Arc Furnace ◽

Continuous Casting Tundish ◽

Argon Oxygen Decarburization ◽

Lf Refining

The inclusions formed in 304L stainless steel for nuclear power produced by the electric arc furnace (EAF)-argon oxygen decarburization furnace (AOD)-ladle furnace (LF)-continuous casting (CC) process were investigated by thermodynamics calculations and experimental results. The results showed that the inclusions after AOD and LF refining were almost the same as the slag composition. The types of inclusions (sizes larger than 5 µm) were mainly CaSiO3 with high SiO2 content at the end of AOD, and Ca2SiO4 with high CaO content at the end of LF. The Al2O3 and MgO content of inclusions increased from AOD to LF. There were two types of inclusions in the tundish: CaO-SiO2-Al2O3-MgO and CaO-SiO2-Al2O3-MgO-MnO inclusions with MgO·Al2O3 spinel precipitation. The content of Al2O3 in the inclusions increased rapidly with the decrease in temperature from the end of LF refining to continuous casting, as calculated using FactSage6.3 software. The rapid increase of Al2O3 in the CaO-SiO2-Al2O3-MgO-(MnO) inclusions promoted the precipitation of MgO·Al2O3 spinel in continuous casting tundish, suggesting mechanisms for the formation of inclusions in the 304L stainless steel.

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Effect of Basicity of Refining Slag on the Inclusions in BN4 Stainless Steel

AISTech2020 Proceedings of the Iron and Steel Technology Conference ◽

10.33313/380/167 ◽

2020 ◽

Author(s):

L. Zhang ◽

Q. Ren ◽

Y. Ren ◽

J. Zhang

Keyword(s):

Stainless Steel ◽

Refining Slag

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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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