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Refining process for producing spring steel through electric furnace

A spring steel, electric furnace smelting technology, applied in electric furnace, process efficiency improvement, furnace and other directions, can solve the problems such as difficult control of molten steel temperature fluctuation, high requirements, difficult desulfurization, etc., to maintain good reducibility and reduce the secondary molten steel. Stable effect of oxidation and electric furnace tapping deoxidation alloying composition

Inactive Publication Date: 2019-12-20
MAANSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Chinese invention patent discloses a smelting process for the control of inclusions in spring steel. The inclusions are controlled by controlling the alkalinity of the refining slag to 0.7-1.4. However, desulfurization is difficult at this alkalinity, especially for molten steel with a high initial sulfur content. In actual production, the refining slag is thinner at this alkalinity, the temperature fluctuation of molten steel is not easy to control, and the requirements for molten iron and operation are higher, and it is also necessary to add quartz sand for slagging

Method used

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  • Refining process for producing spring steel through electric furnace
  • Refining process for producing spring steel through electric furnace
  • Refining process for producing spring steel through electric furnace

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Comparison scheme
Effect test

Embodiment 1

[0027] A kind of electric furnace production refining process of spring steel of the present embodiment, its steps are:

[0028] Step 1: electric furnace smelting;

[0029] a) Using scrap steel and molten iron as raw materials, molten iron S≤0.060%, no need for pretreatment of molten iron, dephosphorization of slag flow under low temperature conditions in the early stage of electric furnace, to ensure that the finished phosphorus meets product requirements;

[0030] b) Eccentric furnace bottom tapping is adopted to prevent slag dropping, and the amount of refined phosphorus return is ≤0.005%; the tapping temperature is above 1620°C to ensure the fluidity of LF entering the top slag, and no high requirements are put forward for the carbon at the end of the electric furnace, which is convenient for electric furnace operation , to create good conditions for on-site mass production and stable production rhythm, and at the same time, it can increase the content of SiO2 in the slag,...

specific Embodiment 1

[0039] Specific embodiment 1, steel type is 55SiCr: step is as follows:

[0040] (1) Electric furnace smelting: molten iron ratio 41%, electric furnace tapping carbon 0.13%, phosphorus 0.005%, tapping temperature 1631°C, tapping amount 111 tons, calculated according to the formula, low carbon low titanium ferrosilicon theoretical addition amount is 1782 kg , the actual amount added is 1774 kg, LF’s inbound silicon is 1.01%, and phosphorus is 0.006%;

[0041] (2) LF furnace smelting: During the LF smelting process, the amount of lime added is 792 kg, the total amount of calcium carbide is 150 kg, the silicon calcium barium is 150 kg, and 70 kg of silicon carbide is added during the slag preservation period to maintain the reducibility of the top slag and the white slag retention time After 48 minutes, the composition of the final slag is shown in the table below, the basicity is 1.88, and the TFe+MnO is 0.60%;

[0042]

[0043] (3) The smelting of RH furnace adopts deep vac...

Embodiment 2

[0045] A kind of electric furnace production refining process of spring steel of the present embodiment, its steps are:

[0046](1) Electric furnace smelting: the steel type is 55SiCr, the molten iron ratio is 41%, the electric furnace tapping carbon is 0.11%, phosphorus is 0.006%, the tapping temperature is 1641°C, and the tapping amount is 110 tons. Calculated according to the formula, low carbon and low titanium ferrosilicon theory The added amount is 1771 kg, the actual added amount is 1748 kg, LF inbound silicon is 1.02%, phosphorus is 0.008%;

[0047] (2) LF furnace smelting: During the LF smelting process, the amount of lime added is 809 kg, the total amount of calcium carbide is 140 kg, the silicon calcium barium is 100 kg, and 60 kg of silicon carbide is added during the slag preservation period to maintain the reducibility of the top slag and the white slag retention time After 55 minutes, the composition of the final slag is shown in the table below, the basicity is...

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Abstract

The invention discloses a refining process for producing spring steel through an electric furnace, and belongs to the technical field of steel smelting. The refining process comprises the steps of firstly, electric furnace smelting, wherein (a) steel scraps and molten iron are adopted as raw materials, (b) eccentric bottom tapping is adopted for preventing slag discharging, the refining rephosphorization quantity is smaller than or equal to 0.005%, the tapping temperature is 1620 DEG C or above, and (c) argon bottom blowing and stirring are carried out in the whole electric furnace tapping process; secondly, LF furnace smelting, wherein (a) lime, calcium carbide and silicon calcium barium are used for deoxidization and slagging in the early stage, and silicon carbide and calcium carbide are used for slag maintaining in the later stage, (b) components of refining slag are required to comprise 48%-55% of CaO, 23%-28% of SiO, smaller than 15% of Al2O3, 5%-8% of MgO and not larger than 0.8% of TFe+MnO; and thirdly, RH smelting. By means of the refining process, the components of the refining slag can be precisely controlled, and quartz sand does not need to be added for slag adjusting;meanwhile, stable control over the molten steel temperature and the components of the refining slag can be guaranteed through the manners of slag quantity control, stirring control, process slag maintaining and the like, and secondary oxidation of molten steel is reduced; and the deoxidization capacity of the refining slag is high, and the aims of deep deoxidization and deep desulfuration are achieved effectively.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a refining process for producing spring steel in an electric furnace. Background technique [0002] Spring steel is widely used in aircraft, automobiles, railway vehicles and other transportation tools and construction machinery and other equipment. It is the material for manufacturing various coil springs, torsion springs, leaf springs and other springs with similar functions. At present, the main spring steel refining slag process is low-alkalinity slag, such as a Chinese invention patent for a spring steel refining method. Compared with it, this patent does not use quartz sand, magnesia and other materials, but directly adjusts it through a deoxidizer. The slag reduces the risk of secondary oxidation, and the stability of inclusion control is further improved. The Chinese invention patent discloses a smelting process for the control of inclusions in spring ste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/54C21C7/06C21C7/10C21C7/064
CPCC21C5/54C21C7/06C21C7/0645C21C7/10Y02P10/20
Inventor 李小虎高振波龚志翔王尚何云龙
Owner MAANSHAN IRON & STEEL CO LTD
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