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Calcium treatment method under special steelmaking process

A calcium treatment and process technology, applied in the direction of improving process efficiency, etc., can solve problems such as lack of quality, and achieve the effects of improving purity, obvious economic benefits, and stable calcium yield

Active Publication Date: 2014-03-05
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above patents disclose the calcium treatment method under normal process conditions, but the calcium treatment effect is related to the process parameters of the calcium wire feeding, such as molten steel temperature, argon blowing flow rate, feeding amount and other parameters. Under special steelmaking process conditions such as How should calcium treatment be carried out in molten iron pretreatment—converter—LF—RH—LF—continuous casting process, and whether it can guarantee a better calcium treatment effect? ​​There is no better solution at present

Method used

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Examples

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Embodiment example 1

[0017] This example provides a calcium treatment method under a special steelmaking process, which mainly adopts deep desulfurization of molten iron pretreatment, oxygen control at the end point of converter, rapid white slag production in LF furnace and process aluminum control, quartz sand adjustment of alkalinity and slag at the end point of ladle Measures such as fluidity, RH low vacuum long-term degassing treatment, secondary LF temperature-adjusting slag calcium treatment, prolonging the soft blowing time before and after calcium treatment, and continuous casting process protection pouring have improved the purity of molten steel and the pass rate of steel plate flaw detection. The yield rate of calcium is guaranteed, and the effect of calcium treatment is improved.

[0018] In this example, the hot metal is pretreated for desulfurization, and CaO+Mg powder is injected to remove the sulfur content of the hot metal to 0.0020%, and the slagging treatment is carried out; the...

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PUM

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Abstract

The invention relates to a calcium treatment method implemented under a special steelmaking process. The calcium treatment method is characterized by comprising the following steps: carrying out desulfurization in a molten iron pretreatment process, namely, blowing CaO+Mg powder to desulfurize the molten iron until the sulfur content is 0.0018 to 0.0022 percent, and slagging off after the desulfurization; controlling the oxygen content at an end point of a converter within 650ppm in an converter process; ensuring the vacuum degree to be less than or equal to 300Pa in the RH (Ruhrstahl Heraeus) process, and maintaining the vacuum degree for 10 to 30 minutes; and secondarily returning the molten iron subjected to RH treatment to an LF (Ladle Furnace), adjusting the temperature, slagging after the RH treatment is completed, then conducting the calcium treatment, ensuring the feeding speed of a calcium line to be 180 to 200m / min, ensuring the feeding quantity of steel to be 1.4m / t, and controlling the bottom-blowing flow rate at 50 to 100 NL / min. By adopting the method, the impurities can be gradually converted from primary silicon manganate to calcium aluminosilicate, so that the quantity of the impurities per unit area of a steel plate can be remarkably reduced and is reduced from 87 to 100 / mm<2> to 12 to 25 / mm<2>. After the RH vacuum and calcium treatment, the type of the impurities is changed, and a product is deviated to the side of CaO-CaS; the size of the impurities in a tundish is relatively small, the impurities with the size being less than 10 micrometers account for 99.61 percent, and the impurity with the size being more than 30 micrometers is not found. By adopting the method, the molten steel purity and the steel plate flaw detection qualification rate can be improved, the calcium yield is stabilized at 20 percent or more, and the economic benefit is obvious.

Description

technical field [0001] The invention relates to a steelmaking process, in particular to a calcium treatment method under a special steelmaking process, and belongs to the technical field of metal smelting processes. Background technique [0002] The steelmaking production process usually includes molten iron pretreatment process, converter process, refining process, and continuous casting process; in the refining process, calcium treatment technology is used to deform the sulfide inclusions and oxide inclusions in molten steel. The brittle Al with high melting point in steel can be made by calcium treatment technology 2 o 3 The inclusions are denatured into low-melting calcium-aluminate inclusions with high calcium content, which are easy to float and remove, improve the purity of molten steel, and prevent nodulation and blockage at the nozzle; at the same time, the formation of CaS inhibits the production and aggregation of MnS, reducing the impact of large MnS inclusions ...

Claims

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Application Information

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IPC IPC(8): C21C7/00C21C1/02C21C7/10C21C7/064
CPCY02P10/20
Inventor 王攀峰靳星聂真来刘军曹余良
Owner NANJING IRON & STEEL CO LTD
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