Method for smelting ferritic stainless steel from total molten iron

A ferrite and full iron technology, applied in the field of stainless steel smelting process, can solve the problems of increased production cost, impact on production capacity, high power consumption, etc., and achieve the effect of cost saving and power saving

Inactive Publication Date: 2006-07-05
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The original smelting process must use an electric furnace to melt scrap steel, alloys and part of the molten iron, which is also feasible in terms of technology, but the use of an electric furnace to smelt stainless steel mother liquor has the disadvantage of relatively high power consumption. The power consumption per ton of steel is 320-360kw

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] AOD smelting process

[0046] Hot metal composition: C 4.0%~4.3%, Mn 0~0.20%, Si 0~0.05%, S 0~0.020%, P0~0.030%, Cr 0~0.5%, Ni 0~0.5%;

[0047] Hot metal temperature: 1100-1300 °C, hot metal weight: 90-95 tons;

[0048] Mix the molten iron into the AOD converter, measure the temperature of the molten iron, and perform blowing according to the oxygen supply and gas supply standards specified in the blowing mode in Table 2;

[0049] Add 4-15kg / t of ferrosilicon steel to raise the temperature when blowing is started, and raise the temperature of the molten pool to 1550-1600°C; continue to blow oxygen to decarburize and raise the temperature.

[0050] Cumulative oxygen supply reaches 30-33Nm 3 When / t, the temperature of the molten pool is about 1670-1720°C, and the ferrochrome alloy is added continuously in small batches (2-3 tons / minute), so as to keep the temperature of the molten pool stable, and a total of 250-280kg / ton of ferrochromium is added;

[0051] When the a...

Embodiment 2

[0058] Hot metal composition: C 3.05%, Mn 0.05%, Si 0.00%, S 0.023%, P 0.019%, Cr0.03%, Ni 0.01%;

[0059] Hot metal temperature: 1296°C, hot metal weight: 91 tons;

[0060] Add Si-Fe 488kg to heat up when blowing begins;

[0061] Cumulative oxygen supply up to 3500Nm 3 Start to add 32300kg of ferrochrome alloy continuously;

[0062]The blowing mode is shown in Table 3:

[0063] table 3

[0064] stage

[0065] C

[0066] Molten steel temperature at the end of decarburization: 1725°C;

[0067] Add reducing agent ferrosilicon 2689kg to reduce;

[0068] After the reduction, desulfurization operation is carried out, and 1500kg of lime and 1100kg of fluorite are added for desulfurization.

[0069] C

[0070] Tapping molten steel temperature: 1670°C Tapping molten steel weight: 123 tons

Embodiment 3

[0073] Hot metal temperature: 1250°C, hot metal weight: 90 tons

[0074] At the beginning of blowing, add Si-Fe 488kg to raise the temperature

[0075] Cumulative oxygen supply up to 3450Nm 3 Begin to continuously add 32000kg of ferrochrome alloy.

[0076] The blowing mode is shown in Table 4:

[0077] Table 4

[0078] stage

Si, Al oxidation

main blow

Dynamic 1

Dynamic 2

Dynamic 3

restore

desulfurization

Oxygen supply Nm 3

700

7300

7800

7940

8090

Top Gun O 2 flow

0

140

0

0

0

0

0

Outlet O 2 flow

110

110

60

40

30

0

0

Tuyere N 2 flow

30

30

60

80

110

0

0

Air outlet Ar flow

0

0

0

0

0

110

110

[0079] C

mn

Si

S

P

Cr

Ni...

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PUM

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Abstract

This invention relates to a molten iron smelting method of ferritic stainless steel which includes: a) temperature-controlled smelting. The temperature is raised to 1580~1600 deg.C before converting. Ferrosilicon containing 4~15kg of steels per ton is added followed by temperature-raising. b) When temperature in molten pool is raised to 1670~1720 deg.C, chromium-iron alloy is added at a rate of 2~3 ton per minute with a total amount of up to 250~280 kg per ton of steel. Then hold the temperature. c) Decarbonization, when it is finished, the carbon concentration is 0.03~0.05% and the temperature is held at 1700~1730 deg.C. d) Reduction and desulfurization. This invention adopts hot metal smelting all through the process and avoids the influences of impure waste iron. Besides the AOD direct smelting technique doesní»t need any crude stainless steel liquid in electric furnace.

Description

technical field [0001] The invention belongs to the field of stainless steel smelting technology. Background technique [0002] At present, the traditional process used in the field of stainless steel smelting is: EAF+AOD+(VOD), which uses scrap steel + alloy to melt into a stainless steel mother liquor (rough smelting molten steel) with a certain temperature and composition in EAF, and then puts the stainless steel mother liquor (rough smelting molten steel) into Refining in AOD furnace. [0003] The existing ferritic stainless steel smelting process is as follows: [0004] Scrap steel (adding molten iron)→electric furnace smelting→AOD refining→(VOD refining)→continuous casting [0005] Among them, AOD refining process: [0006] Mother liquor composition: C 1.0%~3.0%, Mn 0~0.2%, Si 0~0.2%, S 0~0.020%, P0~0.030%, Cr 13.0%~14.0%, Ni 0~0.5%; mother liquor temperature: 1500 ~1580℃, mother liquor weight 110~115 tons. [0007] AOD smelting process: [0008] Put the electric...

Claims

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Application Information

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IPC IPC(8): C22C33/04C22C38/18
Inventor 池和冰江庆元史金强张海清
Owner BAOSHAN IRON & STEEL CO LTD
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