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lf furnace desulfurization control carbon nitrogen control method

A control method and technology of molten steel, applied in the field of metallurgy, can solve problems such as unstable control ability of desulfurization process, improvement of molten steel production quality, insufficient desulfurization capacity, etc., and achieve the effect of ingenious design, promoting slag melting, and increasing the contact area of ​​steel slag

Active Publication Date: 2019-03-26
SHANGHAI MEISHAN IRON & STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the long heating time and insufficient desulfurization ability in the actual LF furnace refining process, the average treatment cycle is 68 minutes, which leads to serious carburization and nitrogen increase in the process of processing molten steel. Affect the stability of production, resulting in the improvement of the quality of molten steel production and downgrading
In order to solve this technical problem, those skilled in the art are also constantly trying, but most of the methods used at present have high cost, and it is difficult to effectively control the content of sulfur. Therefore, there is an urgent need for a new solution to solve this technology. question

Method used

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  • lf furnace desulfurization control carbon nitrogen control method
  • lf furnace desulfurization control carbon nitrogen control method
  • lf furnace desulfurization control carbon nitrogen control method

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Experimental program
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Effect test

Embodiment 1

[0020] Manufacture order number 270872 steel type JU6716A6 is processed in a 250-ton LF furnace for a total period of 52 minutes, the entry temperature is 1611°C, [C]=0.0314%, [S]=0.006%; the set flow rate of the bottom blowing at the entry station is 300L / min, observe Bottom blowing effect is good, add lime 3.8kg / t. steel, and add 200kg high aluminum deoxidizer at the same time for slag deoxidation; use 11 levels of voltage and 6 levels of current for submerged arc heating to heat up the slag for about 8 minutes, the slag turns yellow, and the temperature is measured Oxygenation, measured temperature 1592°C, oxygen content 358ppm, feed Al wire, carry out deoxidation treatment of molten steel, control Alt in the steel to the middle limit Al of the target range t =0.03%, add 520kg ferrosilicon alloy, add 180kg high alumina deoxidizer, 3.5 Kg / t. steel lime, heat for 15min, stop heating, set the flow rate to 180 L / min, stir with bottom blowing for 3 minutes, and turn off the botto...

Embodiment 2

[0022] Manufacture order number 517801, steel type IV5810B2, treatment time in LF furnace 56min, pure treatment cycle 31.3min; composition of steel type entering station [C]=0.0265%, [S]=0.0055%, bottom blowing flow rate of entering station 500L / min, The thickness of the slag layer is 210mm. Short-arc heating is selected for treatment. The heating time is 5 minutes. Heating rapidly, the heating time is 11 minutes, and the temperature is measured at 1601°C. At this time, the aluminum wire is fed to adjust the Al in the steel. t At the same time, add 530kg ferrosilicon alloy, add 3.5 Kg / t. steel lime, 100kg high aluminum slag for 8min deep desulfurization treatment, observe the slag condition, it has become white slag, increase the flow rate of argon to 180 L / min, stir for 3min to increase the steel type Desulfurize the contact area, add 200kg of high-aluminum slag again, reheat for 5 minutes, and heat up at 3.5 ℃ / min, further desulfurize and heat up, stir weakly for 3 minutes, ...

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Abstract

The invention relates to a LF furnace desulphurization carbon-control nitrogen-protection controlling method. The controlling method comprises the following steps: 1) pull-in molten steel is observed, a rapid temperature thermocouple is used for temperature measurement and sampling is carried out, 2) after slugging the molten steel in the step 1), under condition that the slag amount is insufficient, and the fluidity is good, the molten steel is easily exposed, an electrode is brushed, at the same time, desulfurized lime and a high-aluminum deoxidizer submerged arc material are continuously added, 3) when the molten steel temperature is increased to 1590-1600 DEG C, the surface of the molten steel is covered by a layer of protection slag, then submerged-arc heating is carried out, the deoxidation depth is controlled, white residues are generated and deep desulphurization is performed, submerged arc heating is carried out for carbon protection, the nitrogen is controlled; and 4) the dedusting opening degree is adjusted at 20-40% for stabilizing the micro-positive pressure in the furnace, the micro-positive pressure atmosphere in the furnace is guaranteed during a whole processing course of a LF furnace, according to the practical status of ladle permeability, and the argon flow at each phase is set in a reasonable mode.

Description

technical field [0001] The invention relates to a control method for controlling carbon and nitrogen for desulfurization, in particular to a control method for controlling carbon and nitrogen for LF furnace desulfurization, and belongs to the technical field of metallurgy. Background technique [0002] LF furnace (LADLE FURNACE) is the ladle refining furnace, which is the main refining equipment outside the furnace in steel production. LF furnace generally refers to the refining furnace in the steel industry. At present, steel mills produce high-grade pipeline steel series such as X70, which must meet the requirements of ultra-low sulfur [S]≤0.002%, low phosphorus, low nitrogen [N]≤50ppm and low carbon [C]≤0.05% . Reduce the S element in the molten steel, effectively improve the low-temperature impact toughness of the steel and the hydrogen-induced cracking (HIC) resistance of the steel. Due to the long heating time and insufficient desulfurization capacity in the actual ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/064C21C7/06
Inventor 詹起梅曹艳玲马征魏宇霖虞大俊刘正祥
Owner SHANGHAI MEISHAN IRON & STEEL CO LTD
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