CN103045804A - Method for smelting stainless steel with ultra-low carbon and nitrogen content - Google Patents
Method for smelting stainless steel with ultra-low carbon and nitrogen content Download PDFInfo
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- CN103045804A CN103045804A CN2012105666113A CN201210566611A CN103045804A CN 103045804 A CN103045804 A CN 103045804A CN 2012105666113 A CN2012105666113 A CN 2012105666113A CN 201210566611 A CN201210566611 A CN 201210566611A CN 103045804 A CN103045804 A CN 103045804A
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Abstract
The invention belongs to the technical field of preparation methods for stainless steel, particularly relates to a method for smelting stainless steel with ultra-low carbon and nitrogen content, and mainly solves the problem that the molten steel temperature falls greatly because of untight sealing and long processing time for aligning a ladle hanging-in tank to the of a bottom argon blowing top during stainless steel smelting with ultra-low carbon and nitrogen content through VOD (vacuum oxygen decarburization). The technical scheme is that the ratio of the internal diameter of a single-nozzle dip pipe of a single-nozzle refining furnace to that of a ladle is controlled, two bottom blowing bricks are arranged at the bottom of the ladle, and the method for smelting the stainless steel with ultra-low carbon and nitrogen content is finished through two steps under certain initial conditions: (1) inserting the single-nozzle dip pipe into molten steel of the ladle and connecting two bottom argon blowing pipes of the single-nozzle refining furnace; and (2) finishing smelting the stainless steel with the C and N content smaller than 0.025% in 45min-75min according to different chromium contents. The method has the advantages that the decarburization and the denitrification speeds are high, carbon and nitrogen addition in the smelting process is avoided, and seal rings are saved.
Description
Technical field
The invention belongs to stainless steel preparation method technical field, be specifically related to a kind of method of smelting ultralow-carbon nitrogen stainless steel.
Background technology
The method of at present extensive smelting ultralow-carbon nitrogen stainless steel is VOD and AOD method, and single-mouth refining furnace also only is used for smelting ultralow-carbon nitrogen carbon steel.1. VOD (ladle oxygen decarburization method in the vacuum tank) adopts the pot type vacuum environment, top blast oxygen, argon bottom-blowing reaches the purpose of smelting ultralow-carbon nitrogen stainless steel, 1560 ℃～1680 ℃ of control liquid steel temperatures, the carbon content 0.2%～0.6% of arriving at a station, under the condition of nitrogen content 0.005%～0.03%, ladle and molten steel vacuumize after all entering tank, control oxygen flow and argon bottom-blowing flow stirring molten steel reaches decarburization denitrogenation smelting ultralow-carbon nitrogen stainless steel under the vacuum, it is large that present method adopts the pot type vacuum to produce splash, smelting cycle is long, and the sealing-ring life-span is low, short problem of anti-material life-span of ladle.2. AOD(argon gas oxygen mixes and blows decarbonizing furnace) adopt argon gas and oxygen to mix the blowing decarburization according to different ratios, 1460 ℃～1560 ℃ of control liquid steel temperatures, the carbon content 0.9%～2.5% of arriving at a station under the condition of nitrogen content 0.03%～0.08%, adds the AOD stove and smelts.But can only smelt the ultra-low carbon nitrogen stainless steel of low chromium content, can not smelt chromium content greater than 14% ultra-low carbon nitrogen stainless steel.3. single-mouth refining furnace adopts the pot type vacuum environment, top blast oxygen, argon bottom-blowing reaches the purpose of smelting ultralow-carbon nitrogen carbon steel, 1560 ℃～1680 ℃ of control liquid steel temperatures, the carbon content 0.02%～0.08% of arriving at a station, under the condition of nitrogen content 0.001%～0.004%, single mouth soaking tub immerses in the ladle molten steel finishes the decarburization denitrogenation.Present method has splash little, and smelting cycle is short, and the anti-material life-span of soaking tub is long, does not use the advantage of sealing-ring, but owing to only be used for the smelting carbon steel, and to single mouth soaking tub internal diameter: the ratio of ladle internal diameter, ladle bottom blowing brick quantity does not have particular requirement.
Summary of the invention
The present invention is poorly sealed during mainly for VOD smelting ultralow-carbon nitrogen stainless steel, and ladle hangs in tank, and to aim at treatment time of argon bottom-blowing top long and cause the liquid steel temperature larger problem that descends, and a kind of method of smelting ultralow-carbon nitrogen stainless steel is provided.
The present invention addresses the above problem the technical scheme of taking to be:
A kind of method of smelting ultralow-carbon nitrogen stainless steel, wherein: single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.4～0.6, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1560～1660 ℃, Quality Fraction of Carbonium is 0.2～0.6% in the molten steel, the massfraction of nitrogen is 0.005～0.025%, and the massfraction of chromium is to carry out following steps under 11～22% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 400～700mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 70000～50000Pa, lower oxygen lance position to 2000～2400mm, oxygen flow is 17～20Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1700～1900mm, and oxygen flow is adjusted to 10～16Nl/h/t steel, drops to 200～1000Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 40～80Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, steel stirred 2 minutes, and the decarburization denitrogenation finishes, and finishes the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge.
The present invention adopts technique scheme, and is poorly sealed when efficiently solving VOD smelting ultralow-carbon nitrogen stainless steel, and ladle hangs in tank and aims at the treatment time length of argon bottom-blowing top and cause the larger problem of liquid steel temperature decline.
Embodiment
Embodiment 1
A kind of method of smelting ultralow-carbon nitrogen stainless steel, single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.4, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1560 ℃, Quality Fraction of Carbonium is 0.2% in the molten steel, the massfraction of nitrogen is 0.025%, and the massfraction of chromium is to carry out following steps under 11.3% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 400mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 70000Pa, lower oxygen lance position is to 2000mm, and oxygen flow is the 17Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1700mm, and oxygen flow is adjusted to the 10Nl/h/t steel, drops to 200Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 40Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, and steel stirred 2 minutes, and the decarburization denitrogenation finishes, finish the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge, according to massfraction tap to tap time of chromium in the steel be 45min.
Embodiment 2
A kind of method of smelting ultralow-carbon nitrogen stainless steel, single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.45, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1610 ℃, Quality Fraction of Carbonium is 0.3% in the molten steel, the massfraction of nitrogen is 0.005%, and the massfraction of chromium is to carry out following steps under 11.5% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 500mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 60000Pa, lower oxygen lance position is to 2200mm, and oxygen flow is the 18Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1800mm, and oxygen flow is adjusted to the 13Nl/h/t steel, drops to 400Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 50Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, and steel stirred 2 minutes, and the decarburization denitrogenation finishes, finish the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge, according to massfraction tap to tap time of chromium in the steel be 50min.
Embodiment 3
A kind of method of smelting ultralow-carbon nitrogen stainless steel, single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.55, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1630 ℃, Quality Fraction of Carbonium is 0.35% in the molten steel, the massfraction of nitrogen is 0.017%, and the massfraction of chromium is to carry out following steps under 11.6% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 550mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 60000Pa, lower oxygen lance position is to 2300mm, and oxygen flow is the 18Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1900mm, and oxygen flow is adjusted to the 12Nl/h/t steel, drops to 500Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 80Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, and steel stirred 2 minutes, and the decarburization denitrogenation finishes, finish the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge, according to massfraction tap to tap time of chromium in the steel be 54min.
Embodiment 4
A kind of method of smelting ultralow-carbon nitrogen stainless steel, single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.54, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1600 ℃, Quality Fraction of Carbonium is 0.42% in the molten steel, the massfraction of nitrogen is 0.012%, and the massfraction of chromium is to carry out following steps under 17.5% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 600mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 60000Pa, lower oxygen lance position is to 2100mm, and oxygen flow is the 20Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1800mm, and oxygen flow is adjusted to the 13Nl/h/t steel, drops to 300Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 60Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, and steel stirred 2 minutes, and the decarburization denitrogenation finishes, finish the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge, according to massfraction tap to tap time of chromium in the steel be 70min.
Embodiment 5
A kind of method of smelting ultralow-carbon nitrogen stainless steel, single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.58, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1620 ℃, Quality Fraction of Carbonium is 0.5% in the molten steel, the massfraction of nitrogen is 0.01%, and the massfraction of chromium is to carry out following steps under 21.7% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 670mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 70000Pa, lower oxygen lance position is to 2300mm, and oxygen flow is the 20Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1800mm, and oxygen flow is adjusted to the 13Nl/h/t steel, drops to 500Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 55Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, and steel stirred 2 minutes, and the decarburization denitrogenation finishes, finish the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge, according to massfraction tap to tap time of chromium in the steel be 75min.
Claims (1)
1. the method for a smelting ultralow-carbon nitrogen stainless steel, it is characterized in that: single mouth soaking tub internal diameter of control single-mouth refining furnace and the ratio of ladle internal diameter are 0.4～0.6, establish two bottom blowing bricks at ladle bottom, the control liquid steel temperature is 1560～1660 ℃, Quality Fraction of Carbonium is 0.2～0.6% in the molten steel, the massfraction of nitrogen is 0.005～0.025%, and the massfraction of chromium is to carry out following steps under 11～22% the starting condition:
(1) after molten steel arrives at a station, single mouth soaking tub is inserted 400～700mm place in the ladle molten steel, connect two BOTTOM ARGON BLOWING tracheaes of single-mouth refining furnace;
(2) be evacuated down to 70000～50000Pa, lower oxygen lance position to 2000～2400mm, oxygen flow is 17～20Nl/h/t steel, and wherein a bottom blowing brick argon flow amount is the 0.2Nl/min/t steel, and another piece is not opened, along with CO+CO
2The reduction of massfraction, vacuum tightness descends, and increasing bottom blowing brick argon flow amount is the 1Nl/min/t steel, and oxygen lance position is reduced to 1700～1900mm, and oxygen flow is adjusted to 10～16Nl/h/t steel, drops to 200～1000Pa and CO+CO to vacuum tightness
2In the time of＜20%, carry the oxygen rifle and stop oxygen blast, establish another piece bottom blowing brick argon flow amount 0.1Nl/min/t steel newly, increase and stir decarburization, when vacuum tightness drops to 40～80Pa, when being 0.015% according to carbon and oxygen balance calculating Quality Fraction of Carbonium, wherein oxygen utilization rate is 0.38, turn the bottom blowing brick argon flow amount of initial use down to the 0.1Nl/min/t steel, the bottom blowing brick argon flow amount that uses after increasing is to 2Nl/min/t, steel stirred 2 minutes, and the decarburization denitrogenation finishes, and finishes the smelting ultralow-carbon nitrogen stainless steel according to different steel grade killings and slag charge.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1165541A (en) * | 1995-08-01 | 1997-11-19 | 新日本制铁株式会社 | Process for vacuum refining of molten steel |
| CN2432219Y (en) * | 2000-06-09 | 2001-05-30 | 北京科技大学 | Multifunctional multiple blowing single nozzle refining furnace |
| CN101792845A (en) * | 2009-11-20 | 2010-08-04 | 北京科大三泰科技发展有限公司 | Method for smelting ultra-low-carbon steel by using single-nozzle refining furnace |
| CN102251076A (en) * | 2010-05-21 | 2011-11-23 | 宝山钢铁股份有限公司 | RH vacuum refining method of ultra-low carbon stainless steel |
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2012
- 2012-12-21 CN CN201210566611.3A patent/CN103045804B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1165541A (en) * | 1995-08-01 | 1997-11-19 | 新日本制铁株式会社 | Process for vacuum refining of molten steel |
| CN2432219Y (en) * | 2000-06-09 | 2001-05-30 | 北京科技大学 | Multifunctional multiple blowing single nozzle refining furnace |
| CN101792845A (en) * | 2009-11-20 | 2010-08-04 | 北京科大三泰科技发展有限公司 | Method for smelting ultra-low-carbon steel by using single-nozzle refining furnace |
| CN102251076A (en) * | 2010-05-21 | 2011-11-23 | 宝山钢铁股份有限公司 | RH vacuum refining method of ultra-low carbon stainless steel |
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