Physical Simulation Study on Flow Field Characteristics of Molten Steel in 70t Ladle Bottom Argon Blowing Process

Abstract

In the LF refining process, argon blowing at the bottom of ladle can play an important role in unifying the composition and temperature of molten steel and removing inclusions. However, unreasonable bottom argon blowing process can also cause many problems. Slag entrapment and slag surface exposure may occur, affecting the steel quality. Since the working conditions of different enterprises are very different, corresponding optimization is required for specific parameters. There were some problems in 70t ladle of a steel plant, such as unclear control of bottom argon blowing system in different refining periods, unobvious floating removal effect of inclusions in ladle, high total oxygen content and large fluctuation, etc. In this study, a 1:3 physical model was established according to the similarity principle. Then, on this basis, the experimental schemes with different blowing hole positions and argon flow rates were designed for simulation experiments. By means of mixing time measurement, flow field display and oil film measurement, the optimal argon blowing position was double holes 6, 12 (2/3R), and the included angle between them was 135°. The optimal argon flow rate for wire feeding and soft blowing should be 7.6 L/min (corresponding to the actual production of 180 L/min) and 0.6 L/min (corresponding to the actual production of 15 L/min), respectively. According to this scheme, the industrial experiments showed that the contents of total oxygen and nitrogen in the whole process were reduced, the surface density of inclusions in billet was reduced by 11.81% on average, and calcium sulfide and various inclusions containing aluminum were reduced to varying degrees.

Effect of Salt Solution Tracer Dosage on the Transport and Mixing of Tracer in a Water Model of Asymmetrical Gas-Stirred Ladle with a Moderate Gas Flowrate

“…This density difference may affect the fluid flow and measured mixing time data in experiments. Table 1 presents the types and volumes of tracers injected by different researchers into water models of ladles [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62]. It can be observed that the ratio of the tracer-to-water volume varies between 0.038 × 10 −3 and 4.42 × 10 −3 .…”

“…The ratio of the tracer-to-water volume varies by approximately 15 times between these researchers, which could potentially impact the experimental results. [54] 2021 KCl Saturated 100/20/10 333/66.7/33.3 0.3× 10 −3 Shi et al [55] 2021 NaCl Saturated 500 519 0.96 × 10 −3 Ortega et al [56] 2021 KCl Saturated 35 85.4 0.41 × 10 −3 Cheng et al [57] 2021 KCl Saturated 500 428.7 1.17 × 10 −3 Wang et al [58] 2021 NaCl Saturated 24 217 0.11 × 10 −3 Wu et al [59] 2022 KCl Saturated 100 374 0.267 × 10 −3 Zhou et al [38] 2022 NaCl Saturated 200 930 0.215 × 10 −3 Li et al [60] 2023 KCl Saturated 200 384 0.52 × 10 −3 Shan et al [61] 2023 KCl Saturated 100 366 0.27 × 10 −3 Li et al [62] 2024 NaCl Saturated 20 90.8 0.22 × 10 −3…”

Advancements in the Understanding of Single‐Bubble Dynamics: Integrated Experimental and Simulation Studies

“…[ 6–8 ] In metallurgical refining and continuous casting systems, bubbles are introduced into the molten steel to homogenize the temperature and composition of the molten steel, remove inclusions in the molten steel, [ 5 ] and prevent nonmetallic inclusions, such as Al 2 O 3 , from clogging the submerged entry nozzle (SEN) and secondary oxidation of the molten steel. Ladle bottom argon blowing, [ 9 ] tundish with gas curtain, [ 10 ] and SEN argon blowing are typical applications in this field. However, argon blowing may bring the following problems: 1) large bubbles float near the SEN and push away the slag layer, forming slag eyes; and 2) small bubbles are captured by the solidified billet shell deep into the mold along with the molten steel, [ 11,12 ] leading to subcutaneous bubble defects in the casting billet; and 3) small bubbles with inclusions adhering to them flow with the molten steel flow strands and are then captured by the solidified billet shell, [ 13–17 ] leading to cracks in the final product.…”