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LF refining method of low-carbon steel

A low-carbon steel and silicon carbide technology, applied in the field of steelmaking, can solve problems such as adverse effects on molten steel quality and nitrogen absorption in molten steel, and achieve the effect of reducing exposed molten steel, reducing the influence of human factors, and ensuring the quality of molten steel

Pending Publication Date: 2021-07-09
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The existing LF refining process has the following disadvantages: the adjustment of molten steel composition is mainly placed after the first sample. When adjusting the carbon composition in steel, the amount of carbon added to low-carbon steel is often ≥ 0.05%. Gas volume stirring, which inevitably leads to the contact of molten steel with air, causing the molten steel to absorb nitrogen and oxygen, which has a negative impact on the quality of molten steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Use a 120-ton refining furnace to smelt 20CrMnTiH gear steel. The composition requirements of this steel type are: C: 0.17-0.23%, Mn: 0.80-1.20%, Cr: 1.00-1.45%, Si: 0.17-0.37%, Ti: 0.04- 0.10%, the target composition is: C: 0.19%, Mn: 0.88%, Cr: 1.05%, Si: 0.25%, Ti: 0.070%. 120.4 tons of steel were tapped from the primary smelting furnace, and the carbon at the end point of the primary smelting furnace was 0.073%. During the tapping process of the primary smelting furnace, 796kg of silicon-manganese alloy, 468kg of medium-carbon ferromanganese, 686kg of high-carbon ferrochrome, and 1384kg of medium-carbon ferrochrome were added. The carbon content in carbon ferromanganese is 1.56%, the carbon content in high carbon ferrochrome is 7.45%, and the carbon content in medium carbon ferrochrome is 2.08%. After calculation, the alloy added to the primary smelting furnace increased carbon by 0.071%. During the tapping process of the primary smelting furnace, 730kg of lime, 30...

Embodiment 2

[0033]Use a 120-ton refining furnace to smelt 22CrMoH gear steel. The composition requirements of this steel type are: C: 0.19-0.25%, Mn: 0.55-90%, Cr: 0.85-1.25%, Si: 0.17-0.37%, Mo: 0.35- 0.45%, the target composition is: C: 0.22%, Mn: 0.86%, Cr: 1.16%, Si: 0.25%, Mo: 0.39%. 118.6 tons of steel were tapped from the primary smelting furnace, and the carbon at the end point of the primary smelting furnace was 0.083%. During the tapping process of the primary smelting furnace, 787kg of silicon-manganese alloy, 474kg of medium-carbon ferromanganese, 607kg of high-carbon ferrochrome, 1561kg of medium-carbon ferrochrome, and ferromolybdenum were added. 594.9kg, wherein the carbon content in medium-carbon ferromanganese is 1.42%, the carbon content in high-carbon ferrochrome is 7.34%, and the carbon content in medium-carbon ferrochrome is 2.05%. After calculation, the alloy added to the primary smelting furnace increased carbon by 0.068%. During the tapping process of the primary ...

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PUM

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Abstract

The invention relates to an LF (ladle furnace) refining method of low-carbon steel. The comprises the following steps that 1) the endpoint carbon of a primary smelting furnace is controlled to be 0.07-0.09%, and alloy and slag charge are added into the steel along with steel flow in the tapping process of the primary smelting furnace; 2) after molten steel reaches a refining position, power supply begins, silicon carbide and a carburant are added for diffusion deoxidation, and argon is blown at the bottom of a large ladle; and (3) after slagging, power is shut off, argon bottom blowing is conducted for stirring, a primary sample is taken for analysis, the result is analyzed, the content of molten steel components is adjusted according to the targeted component requirement, then argon bottom blowing is conducted for stirring, sampling analysis is conducted again till the components of the molten steel meet the targeted component requirements, and then tapping is conducted to obtain the low-carbon steel. According to the method, the using amount of deoxidizing materials such as the carburant and silicon carbide and the using amount of the bottom blowing argon in the refining diffusion deoxidizing process are quantified, the influence of human factors is reduced, the problems that the using amount of the carburant and the silicon carbide is greatly changed and molten steel components are greatly fluctuated in the refining diffusion deoxidizing process of the molten steel are solved, and standardized operation of the molten steel in the refining process can be facilitated.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, in particular, the invention relates to an LF refining method of low carbon steel. Background technique [0002] The LF refining process is mainly responsible for the tasks of "two removals" and "two adjustments" of molten steel, namely deoxidation, desulfurization, adjustment of molten steel composition and adjustment of molten steel temperature. The general refining process is to add an appropriate amount of alloy and slag to the steel during the tapping of the primary smelting furnace, and then transfer the molten steel to the refining station. First, measure the temperature, then raise the temperature while melting the slag, and add carbonization Silicon, calcium carbide, aluminum particles and other materials are deoxidized, and then a sample is taken to analyze the composition of the molten steel, and the composition of the molten steel is adjusted according to the test results of the f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/06C21C7/072C21C7/076C21C7/00
CPCC21C7/06C21C7/072C21C7/076C21C7/0025Y02P10/20
Inventor 刘兵叶飞来戈文英范斌赵冠夫
Owner SHANDONG IRON & STEEL CO LTD
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