CN101541982B - A ferro-alloy inserting apparatus with reduced absorption of oxygen and absorption of nitrogen and inserting method thereof - Google Patents
A ferro-alloy inserting apparatus with reduced absorption of oxygen and absorption of nitrogen and inserting method thereof Download PDFInfo
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- CN101541982B CN101541982B CN2006800556590A CN200680055659A CN101541982B CN 101541982 B CN101541982 B CN 101541982B CN 2006800556590 A CN2006800556590 A CN 2006800556590A CN 200680055659 A CN200680055659 A CN 200680055659A CN 101541982 B CN101541982 B CN 101541982B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/005—Manufacture of stainless steel
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
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Abstract
The present invention relates to an apparatus for inserting ferro-alloy and inserting method without submerging into slag and liquid steel for reducing absorption of oxygen and absorption of nitrogen capable of inserting ferro-alloy by minimizing an incorporation of oxygen and nitrogen in a ladle treatment process of a steelmaking process upon performing a steelmaking operation, comprising: a supplying tube supplied with ferro-alloy from a hopper to insert it to a ladle and subdivided into an upper part, an inclined middle part, a lower part and having a predetermined hollow; a branched and mounted inert gas blocking unit communicated with the middle of the supplying unit and blocking, as first inert gas, air flowed in at the same time when the ferro-alloy is inserted; a branched and mounted inert gas supplying unit communicated with the base end part of the lower part of the supplying tube and blowing a second inert gas on an inserting path of the ferro-alloy; an inert gas injecting unit packing any one of the lower outer sides of the supplying unit relative to axis direction of the lower thereof and injecting a third inert gas toward the end part of the lower part thereof; and a diffusing unit diffusing the third inert gas injected while packing the supplying tube from the gas injecting unit into the end part of the supplying tube.
Description
Technical field
The present invention relates to a kind of oxygen uptake and inhale the equipment and the feeding method thereof that are used for the feeding iron alloy that nitrogen reduces, more particularly, the present invention relates to a kind of like this oxygen uptake and inhale the equipment and the feeding method thereof that are used for the feeding iron alloy that nitrogen has reduced, namely, when carrying out the stainless steel smelting operation, in Ladle Treatment (LT) technique of process for making, minimize to feed iron alloy by the adding that makes oxygen and nitrogen.
Background technology
Usually, for the refining stainless steel, make stainless molten steel stand the continuous casting of argon oxygen decarburization (AOD) refining by electric furnace, then stand Ladle Treatment (for example ladle refining technique or ladle furnace technique).
At this, after the AOD refining, can also make stainless molten steel stand vacuum oxygen decarburization (VOD) refining.
Before carrying out continuous casting, in the Ladle Treatment technique in such series of process, in Ladle Treatment technique, to be fed in the molten steel with the composition of guaranteeing molten steel and the target of temperature such as the iron alloy of Al, Ti, Fe-Si, Fe-Cr, Fe-Ni and refrigerant, carry out simultaneously the gas stirring refining so that composition and temperature evenly and to inclusion are carried out flotation separation.
So that being exposed to, molten steel feeds iron alloy because be in naked state (naked eye state) by the molten steel that slag is covered in the air, so owing to deteriorated with molten steel purity of reoxidizing of inhaling nitrogen and oxygen uptake and occur molten steel, and when casting, nozzle clogging and surface imperfection in the steelmaking process appear continually.
Fig. 1 illustrates the graphic representation that changes according to the composition of analyzing by the nitrogen content in the molten steel that uses traditional ferro-alloy inserting apparatus in ladle.
Fig. 1 shows the 409 stainless steels (C:0.010% or lower at 90 tons, N:0.010%, Cr:11% to 12%, Ni:0.5% or lower, Si:0.6% or lower, the concentration of the nitrogen of the absorption in ladle Mn:0.6% or lower) before and after the feeding iron alloy, wherein, described stainless steel is through electric furnace refining and AOD refining.That is, Fig. 1 show in ladle after the feeding iron alloy nitrogen concentration and in ladle the increase and decrease of the difference of the nitrogen concentration before the feeding iron alloy.
The concentration that Fig. 1 shows the nitrogen of absorption is increased between 0ppm and the 28ppm and the suction nitrogen of average 9.9ppm occurs.This means that the oxygen in the molten steel increases.Therefore, because increasing of impurity (for example, the oxide compound of molten steel) causes occurring the deteriorated of continuous casting, and the possibility increase that produces mass deviation.
Because in order to realize the target of temperature and composition, the steel grade that is experiencing VOD technique must stand Ladle Treatment technique, so cause the purity of molten steel to descend owing to reoxidizing and inhaling nitrogen, have a strong impact on so that the oxygen uptake that causes during the feeding iron alloy in ladle and the problem of inhaling nitrogen produce the surface quality of nozzle clogging and product when casting.
Although in order to make the generation of inhaling nitrogen minimized and on molten steel, utilize slag to cover molten steel, along with slag increases, and guarantee inevitably the spray eye (plume eye) that produces by being used for feeding the gas stirring of iron alloy.Therefore, when the feeding iron alloy, the still existence that has problems of inhaling nitrogen and reoxidizing.
That is, when the feeding iron alloy, because reoxidizing oxidation product (for example, the TiO that in molten steel, produces
2(fusing point: about 1830 ℃), CaO-TiO
2Class (fusing point: about 1930 ℃), Al
2O
3High-melting-point oxide compounds such as (fusing points: about 2020 ℃)) and because the nitride TiN (fusing point: about 2930 ℃) that inhales the nitrogen generation makes the purity of the finished product descend, when casting nozzle clogging occurs and reduced continuous casting productivity, surface imperfection appears in the steel of hot rolled coil and cold rolling coil when compacting.
For head it off, be called in name " an apparatus and method for insertingferro-alloy of molten steel into a ladle (equipment and the method for the iron alloy of feeding molten steel in the ladle) " the 5th, a kind of equipment and method that prevents from inhaling nitrogen and reoxidizing when feeding iron alloy in ladle disclosed in 211, No. 744 United States Patent (USP)s.Yet the patent of quoting has following problem.
At first, by submergence iron alloy feeding hole iron alloy directly is fed in the molten steel through the feeding pipe, does not therefore almost reoxidize and inhale nitrogen.Yet existence is by the problem of the deteriorated working efficiency that causes of iron alloy feeding pipe and the maintenance issues that is caused by the frequent that feeds the hole.
In addition, the erosion that the corrosion phenomenon that produces because of the reaction between feeding infusibility pipe and the slag/molten steel and infusibility pipe produce because of Melt Stirring can cause feeding the lost of life of infusibility pipe.This corrosion and erosion also may invar reaction in the liquid and the refractory particle that is mingled with and total oxygen content is increased.Except increasing maintenance cost, because frequent and the corrosion of feeding infusibility pipe occur, the difficulty of maintenance can significantly increase.Therefore, the United States Patent (USP) of quoting has many restrictions, and can not be applied to high productivity and the required actually operating of high quality.
In addition, the name 1993-009552 Japanese Patent Publication that is called " Top blowing lance type ladle refining Apparatus (top-blown spray gun shaped steel bag refining unit) " use immersion tube solve molten steel suction nitrogen and since molten steel reoxidize the problems such as the slag that causes increases.Yet, because under the high-temperature molten steel more than 1550 ℃, carry out all operations, so this has effect for preventing from inhaling nitrogen and reoxidizing, but have the life-span of immersion tube and the problem of maintenance thereof.This is the same with the 5th, 211, No. 744 United States Patent (USP)s, because the erosion that the corrosion phenomenon that produces because of the reaction between feeding infusibility pipe and the slag/molten steel and infusibility pipe produce because of Melt Stirring can cause feeding the lost of life of infusibility pipe.This corrosion and erosion also may invar reaction in the liquid and the refractory particle that is mingled with and total oxygen content is increased.Except increasing maintenance cost, because frequent and the corrosion of feeding infusibility pipe occur, the difficulty of maintenance can enlarge markedly.
Summary of the invention
Therefore, propose the present invention and solved the problems referred to above.The object of the present invention is to provide a kind of oxygen uptake and inhale ferro-alloy inserting apparatus and the feeding method thereof that nitrogen reduces, in order to realize the target of temperature and composition, in the stainless steel-making process process, when in the stainless molten steel that refrigerant and various iron alloy is fed in the ladle and when not making described ferro-alloy inserting apparatus be immersed in slag and the molten steel, described ferro-alloy inserting apparatus and feeding method thereof can minimize to reduce the suction nitrogen of molten steel by the adding that makes oxygen and nitrogen, and reoxidize to improve degree of cleaning by restriction.
In order to realize these targets, a kind of oxygen uptake is provided and has inhaled the ferro-alloy inserting apparatus that nitrogen reduces, this equipment comprises: supply-pipe, supply with iron alloy from hopper to described supply-pipe, thereby described iron alloy is fed in the ladle, described supply-pipe is subdivided into middle part, the bottom of top, inclination, and has predetermined hollow; Branch and the rare gas element blocking unit of installing are communicated with the middle part of described supply-pipe, and when the described iron alloy of feeding, described rare gas element blocking unit flows into simultaneously with the first rare gas element blocks air; Branch and the rare gas element feed unit of installing are communicated with the matrix end of the bottom of described supply-pipe, and blow the second rare gas element in the feeding path of described iron alloy; Rare gas element injects the unit, with respect to the direction of principal axis of the bottom of described supply-pipe, and any side of wrapping up the lower outside of described supply-pipe, and inject the 3rd rare gas element towards the end of the bottom of described supply-pipe; Diffusion unit spreads the 3rd rare gas element, wherein, injects the unit from described rare gas element and injects described the 3rd rare gas element to the end of described supply-pipe, and described the 3rd rare gas element wraps up described supply-pipe simultaneously.
At this, described supply-pipe is subdivided into top supply-pipe, middle part supply-pipe and underfeed pipe, and from its matrix end to its sloped-end, described rare gas element feed unit is communicated with the matrix end of described underfeed pipe, and described rare gas element injects any one zone that the unit is configured to wrap up described underfeed pipe.
At this moment, rare gas element injects the unit wraps up the outside of described underfeed pipe with respect to the direction of principal axis of described underfeed pipe any side, described rare gas element feed unit is single ring architecture, described single ring architecture injects the 3rd rare gas element by wrapping up described underfeed pipe to end direction, described rare gas element injects the unit wraps up the outside of described underfeed pipe with respect to the direction of principal axis of described underfeed pipe any side, described rare gas element injects the unit can be the complex loop structure, described complex loop structure is by the first ring structure, the second ring structure and a plurality of junctor consist of, described first ring structure distributes described the 3rd rare gas element equably, described the second ring structure wraps up described underfeed Guan Bingxiang end direction and is infused in equally distributed the 3rd rare gas element in the described first ring structure, and described a plurality of junctors are communicated with described first ring structure with described the second ring structure.
In this case, described rare gas element injects the unit and is formed with predetermined slit along the end of described underfeed pipe, and wherein, the width of described slit is 3.0mm or less than 3.0mm, is preferably more than to equal 0.1mm to less than or equal to 3.0mm.
In addition, the internal divergence angle between the inside of the inside of described diffusion unit and described underfeed pipe is extremely less than 90 ° greater than 0 °.
In addition, a kind of oxygen uptake also is provided and has inhaled the iron alloy feeding method that nitrogen reduces, in ladle, hold the molten steel that is covered by slag, the iron alloy that will be stored in the hopper by top supply-pipe, middle part supply-pipe and underfeed pipe is fed into the described molten steel from the top of described ladle, in the bottom of described ladle, porous plug is installed, said method comprising the steps of: the end of described underfeed pipe is descended; The first rare gas element is fed in the supply-pipe of described middle part; The second rare gas element is fed in the matrix end of described underfeed pipe; By wrapping up the outside of described underfeed pipe, provide the 3rd rare gas element that injects along end direction; Successively described iron alloy is fed into described top supply-pipe, described middle part supply-pipe and described underfeed pipe.
Wherein, in the situation that the underfeed pipe is not immersed in slag and the molten steel, the decline of underfeed pipe is limited by following equation 1.
[equation 1]
y＝h
0-x-c
Wherein, y is to the distance [mm] of the end of underfeed pipe from the inboard of steel ladle cover; h
0To the distance [mm] of ladle bottom from the inboard of steel ladle cover; X is the distance [mm] from the ladle bottom to the molten steel surface; C is the distance [mm] of the end from molten steel surface to the underfeed pipe.
Being limited by following equation 2 apart from x from the ladle bottom to the molten steel surface.
[equation 2]
w＝-51.1×ln(x)+454
(wherein, w is the tonnage of molten steel)
In addition, can move the end of described underfeed pipe, thereby form the distance of 1m to 3m with respect to the surface of molten steel.
At this moment, the injection rate of the time per unit of described the second rare gas element can be 5Nm
3/ hr to 50Nm
3/ hr, the injection rate of the time per unit of described the 3rd rare gas element can be 10Nm
3/ hr to 100Nm
3/ hr.
Beneficial effect
As mentioned above, the invention reside in provides a kind of oxygen uptake and inhales ferro-alloy inserting apparatus and the feeding method thereof that nitrogen reduces, in order to realize the target of temperature and composition, in the stainless steel-making process process, when in the stainless molten steel that refrigerant and various iron alloy is fed in the ladle, described ferro-alloy inserting apparatus and feeding method thereof can minimize to reduce the suction nitrogen of molten steel by the adding that makes oxygen and nitrogen, and reoxidize to improve degree of cleaning by restriction.
Description of drawings
Fig. 1 illustrates by the nitrogen in the molten steel of traditional ferro-alloy inserting apparatus to form the graphic representation that changes according to the oxide compound of molten steel surface;
Fig. 2 is the schematic diagram that illustrates according to ferro-alloy inserting apparatus of the present invention;
Fig. 3 is the partial enlarged drawing that " A " part among Fig. 2 is shown;
Fig. 4 is the partial enlarged drawing that " B " part among Fig. 2 is shown;
Fig. 5 is the general movement concept figure of according to an embodiment of the invention ferro-alloy inserting apparatus;
Fig. 6 illustrates the according to another embodiment of the present invention schematic diagram of ferro-alloy inserting apparatus;
Fig. 7 is the partial enlarged drawing that " A " part among Fig. 6 is shown;
Fig. 8 is the partial enlarged drawing that " B " part among Fig. 6 is shown;
Fig. 9 is the general movement concept figure of according to an embodiment of the invention ferro-alloy inserting apparatus;
Figure 10 is the diagram that the flow velocity to the circumference of the underfeed pipe in one embodiment of the invention and in another embodiment of the present invention compares;
Figure 11 is the schematic diagram that according to the preferred embodiment of the invention oxygen uptake is shown and inhales the ferro-alloy inserting apparatus of nitrogen minimizing;
Figure 12 is the partial enlarged drawing that " A " part among Figure 11 is shown;
Figure 13 a and Figure 13 b are the partial enlarged drawings that illustrates respectively by " B " among the Figure 11 that uses one embodiment of the invention and another embodiment of the present invention part;
Figure 14 is the part sectioned view that the diffusion unit of Figure 11 is shown;
Figure 15 is the general movement concept figure that the ferro-alloy inserting apparatus that has according to the preferred embodiment of the invention diffusion unit is shown;
Figure 16 is the diagram that is illustrated in the variation that feeds the nitrogen concentration in the front/rear molten steel of iron alloy in the ladle;
Figure 17 is the diagram that is illustrated in the variation that feeds the oxygen concn in the front/rear molten steel of iron alloy in the ladle;
Figure 18 is the graphic representation that the oxygen partial pressure from the underfeed pipe to molten steel surface when feeding iron alloy in ladle is shown;
Figure 19 is illustrated in the example of prior art and the diagram of the surface defect rate of the volume of the stainless steel hot-rolling in example of the present invention.
Embodiment
Equipment and the feeding method thereof of the feeding iron alloy of according to an embodiment of the invention oxygen uptake and the minimizing of suction nitrogen are described hereinafter, with reference to the accompanying drawings.
Fig. 2 is the schematic diagram that according to an embodiment of the invention oxygen uptake is shown and inhales the ferro-alloy inserting apparatus of nitrogen minimizing.
With reference to Fig. 2, to be used for the temperature of casting and the target of composition in order in the ladle refining platform, realizing, refrigerant and iron alloy F to be weighed, and be fed in the ladle 22 that is soaked with molten steel M, wherein, the decarburization of molten steel M is finished in the decarburization container such as AOD, VOD and converter.
By conveying belt 2 iron alloy F is stored in the hopper 3 from iron alloy storage hopper 1, switch-valve 4 is configured for the feeding of control iron alloy F in the hopper 3 of storage iron alloy F.By supply-pipe 101,102 and 103 iron alloy F is fed into the molten steel M from hopper 3.
The ladle 22 of holding molten steel M comprises by stopping that atmosphere prevents oxidation and can feed the steel ladle cover 21 of iron alloy F, constructs supply-pipe 103 by penetrating steel ladle cover 21.
In one embodiment of the invention, supply-pipe 101,102 and 103 is subdivided into top supply-pipe 101, middle part supply-pipe 102 and underfeed pipe 103, according to the position of hopper 3 and shop equipment, middle part supply-pipe 102 can tilt, as shown in drawings.
On any one zone of middle part supply-pipe 102, branch also is equipped with the rare gas element blocking unit 123 that comprises the first rare gas element feed unit 124, therefore, when supplying with iron alloy F from hopper 3, the feeding path of iron alloy F can be by stopping that comprising oxygen and nitrogen flows at interior air and keep inert atmosphere.
With reference to Fig. 3, with rare gas element blocking unit 123 branches and be mounted to respect to the matrix end of middle part supply-pipe 102 and form more than 90 ° to the angle θ below 180 °
1Thereby rare gas element injects along the direction of the opposite direction that carries out with the feeding of iron alloy F, and being used for effectively, blocks air flows into.
By the rare gas element such as Ar that porous plug the last 23 from be installed in advance ladle 22 bottoms blown, iron alloy F removes a part of slag S in the molten steel top, in order to drop on swimmingly the position that will be spray eye.
At this moment, the composition of molten steel M is expressed as follows with % by weight: C:0 to 0.05%, N:0 to 0.070%, Si:p to 4%, Ti:0 to 0.5%, S: be lower than 0.030%, P: be lower than 0.025%, Cr:11.0% to 30.0%, Ni:0 to 36%.Molten steel M can be the stainless molten steel that is grouped into by other one-tenth, for example, and AISI benchmark 304,316L, 430,446 and 447 stainless steels.Can use through iron alloy and feed other steel of processing as molten steel M.
For iron alloy F is fed among the molten steel M, the feeding hole of underfeed pipe 103 drops to the surface of molten steel M by length control unit 113, and is not immersed in slag and the molten steel.
Usually, length control unit 113 can be the member that can control length, preferably, length control unit 113 is configured to make the end lifting that is positioned at the underfeed pipe 103 directly over the ladle 22, i.e. lifting feeding hole only.
Supply-pipe, more particularly, the end of middle part supply-pipe 102 and/or the matrix end of underfeed pipe 103, be communicated with the rare gas element feed unit 133 that comprises the second rare gas element feed unit 134, therefore, when feeding iron alloy F, the inert gas atmosphere that produces arrives the end of underfeed pipe 103.
Rare gas element feed unit 133 blows the second rare gas element of supplying with from the second rare gas element feed unit 134, so that the second rare gas element sprays from the end of underfeed pipe 103, therefore, when feeding iron alloy F, path at underfeed pipe 103 produces inert atmosphere, when the second rare gas element sprayed from the end of underfeed pipe 103, inert atmosphere was retained the surface that arrives molten steel.
The outside of underfeed pipe 103, more particularly, the circumference of the cylindrical lower part supply-pipe 103 of hollow is provided with single ring architecture 150, single ring architecture 150 and underfeed pipe 103 cavities formed co-axial are with parcel underfeed pipe 103, and single ring architecture 150 comprises the 3rd rare gas element feed unit 154.
With reference to Fig. 4, the 3rd rare gas element that injects near circumference is provided from the 3rd rare gas element feed unit 154 to single ring architecture 150, thereby forms the 3rd inertia gas column with the excircle of underfeed unit 103.
According to equipment, one or two or several the 3rd rare gas element feed unit 154 can be installed.
In the bottom of single ring architecture 150, that is, the side in the end of underfeed pipe 103 forms predetermined slit 151, thereby injects the 3rd rare gas element by slit 151.Slit 151 can be a slit, is preferably line slit 151, thereby injects equably the 3rd rare gas element above the whole circumference of underfeed pipe 103.
In addition, preferably, the 3rd inertia gas column is along advancing towards the direction of the end of underfeed pipe 103 and with the excircle of underfeed pipe 103, and extend to molten steel M from the end, therefore, the 3rd inertia gas column makes the progress path of iron alloy F keep inert atmosphere with the first rare gas element and the second rare gas element of spraying from the inboard of the end of underfeed pipe 103.
In order to inject the 3rd rare gas element, keep simultaneously injecting the surface that shape arrives molten steel M, preferably, the width of slit 151 is below 3.0mm.
When the width of slit 151 surpassed 3.0mm, by continuous theorem, flow velocity was slack-off, and therefore, the 3rd rare gas element can disperse before the surface that arrives molten steel M.
When the width of slit 151 when 0.1mm is following, cause following problem, that is, can not disperse flowing of q.s, perhaps since Ladle Treatment is finished after the CaO powder of injection etc. cause stopping up.Therefore, the most preferred width of slit 151 is extremely less than or equal to 3.0mm more than or equal to 0.1mm.
Fig. 5 is the general movement concept figure of according to an embodiment of the invention ferro-alloy inserting apparatus.
With reference to Fig. 5, iron alloy F enters in the top supply-pipe 101, thereby is fed among the molten steel M by middle part supply-pipe 102 and underfeed pipe 103.
When iron alloy F passes middle part supply-pipe 102, inject the first rare gas element by rare gas element blocking unit 123, thereby blocks air and iron alloy F enter (IG1) simultaneously.
The first rare gas element can be the 8th family's gas or nitrogen such as Ar, more preferably, considers possibility and the manufacturing cost of inhaling nitrogen, and the first rare gas element can be Ar.In addition, in the situation that the austenite steel grade can use nitrogen.
When iron alloy F passed underfeed pipe 103, the surface of the feeding path that the second rare gas element of supplying with by rare gas element feed unit 133 makes iron alloy F from the matrix end of underfeed pipe 103 to molten steel M kept inert atmosphere (IG2).
The second rare gas element can for the 8th family's gas, more preferably can be Ar.Be in the 300 serial austenitic situations at steel grade, also can use nitrogen.
In addition, the 3rd rare gas element disperses by the outside of single ring architecture 150 from the end of underfeed pipe 103, disperses to prevent the second rare gas element, and then keeps the feeding path of iron alloy F to be in inert atmosphere (IG3).
The 3rd rare gas element can be the 8th family's gas, more preferably can be Ar.In addition, because the 3rd rare gas element is so that flow (IG2) of the second rare gas element that sprays from the inboard of underfeed pipe 103 remains in its outside, so preferably, the flow velocity of velocity ratio second rare gas element of the 3rd rare gas element is fast, perhaps, the injection pressure of the 3rd rare gas element is larger than the injection pressure of the second rare gas element.
Fig. 6 illustrates the according to another embodiment of the present invention schematic diagram of ferro-alloy inserting apparatus.
With reference to Fig. 6, to be used for the temperature of casting and the target of composition in order in the ladle refining platform, realizing, refrigerant and iron alloy F to be weighed, and be fed in the ladle 22 that is soaked with molten steel M, wherein, the decarburization of molten steel M is finished in the decarburization container such as AOD, VOD and converter.
By conveying belt 2 iron alloy F is stored in the hopper 3 from iron alloy storage hopper 1, switch-valve 4 is configured for the feeding of control iron alloy F in the hopper 3 of storage iron alloy F.By supply-pipe 301,302 and 303 iron alloy F is fed into the molten steel M from hopper 3.
The ladle 22 of holding molten steel M comprises by stopping that atmosphere prevents oxidation and can feed the steel ladle cover 21 of iron alloy F, constructs supply-pipe 303 and supply-pipe 303 is immersed in the slag by penetrating steel ladle cover 21.
In one embodiment of the invention, supply-pipe 301,302 and 303 is subdivided into top supply-pipe 301, middle part supply-pipe 302 and underfeed pipe 303, according to the position of hopper 3 and shop equipment, middle part supply-pipe 302 can tilt, as shown in drawings.
On any one zone of middle part supply-pipe 302, branch also is equipped with the rare gas element blocking unit 323 that comprises the first rare gas element feed unit 324, therefore, when supplying with iron alloy F from hopper 3, the feeding path of iron alloy F can be by stopping that comprising oxygen and nitrogen flows at interior air and keep inert atmosphere.
With reference to Fig. 7, with rare gas element blocking unit 323 branches and be mounted to respect to the matrix end of middle part supply-pipe 302 and form more than 90 ° to the angle θ below 180 °
1Thereby rare gas element injects along the direction of the opposite direction that carries out with the feeding of iron alloy F, and being used for effectively, blocks air flows into.
By the rare gas element such as Ar that porous plug the last 23 from be installed in advance ladle 22 bottoms blown, iron alloy F removes a part of slag S in the molten steel top, in order to drop on swimmingly the position that will be spray eye.
At this moment, the composition of molten steel M is expressed as follows with % by weight: C:0 to 0.05%, N:0 to 0.070%, Si:p to 4%, Ti:0 to 0.5%, S: be lower than 0.030%, P: be lower than 0.025%, Cr:11.0% to 30.0%, Ni:0 to 36%.Molten steel M can be the stainless molten steel that is grouped into by other one-tenth, for example, and AISI benchmark 304,316L, 430,446 and 447 stainless steels.Can use through iron alloy and feed other steel of processing as molten steel M.
For iron alloy F is fed among the molten steel M, the feeding hole of underfeed pipe 303 drops to the surface of molten steel M by length control unit 313.
Usually, length control unit 313 can be the member that can control length, preferably, length control unit 313 is configured to make the end lifting that is positioned at the underfeed pipe 303 directly over the ladle 22, i.e. lifting feeding hole only.
Supply-pipe, more particularly, the end of middle part supply-pipe 302 and/or the matrix end of underfeed pipe 303, be communicated with the rare gas element feed unit 333 that comprises the second rare gas element feed unit 334, therefore, when feeding iron alloy F, the inert gas atmosphere that produces arrives the end of underfeed pipe 303.
Rare gas element feed unit 333 blows the second rare gas element of supplying with from the second rare gas element feed unit 334, so that the second rare gas element sprays from the end of underfeed pipe 303, therefore, when feeding iron alloy F, path at underfeed pipe 303 produces inert atmosphere, when the second rare gas element sprayed from the end of underfeed pipe 303, inert atmosphere was retained the surface that arrives molten steel.
The outside of underfeed pipe 303, more particularly, the circumference of the cylindrical lower part supply-pipe 303 of hollow, be provided with complex loop structure 350, complex loop structure 350 and underfeed pipe 303 cavities formed co-axial are with parcel underfeed pipe 303, and complex loop structure 350 comprises the 3rd rare gas element feed unit 354.
With reference to Fig. 8, the 3rd rare gas element that injects near circumference is provided from the 3rd rare gas element feed unit 354 to complex loop structure 350, thereby forms the 3rd inertia gas column with the excircle of underfeed unit 303.
According to equipment, one or more the 3rd rare gas element feed units 354 can be installed.
In the first ring structure 355 of the circumference of parcel underfeed pipe 303, the 3rd rare gas element that distributes equably and supply with from the 3rd rare gas element feed unit 354 along the circumferential direction of underfeed pipe 303.The opposite side of a side that for this reason, is connected with the 3rd rare gas element feed unit 354 can have unconnected shape.
Almost be evenly distributed on the 3rd rare gas element in the first ring structure 355 by being fed into the second ring structure 353 with respect to several junctors 352 with first ring structure 355 massiveness along the circumference of underfeed pipe 303.
In the bottom of the second ring structure 353 of complex loop structure 350, that is, in the side of the end of underfeed pipe 303, form predetermined slit 351, thereby inject the 3rd rare gas element by slit 351.Slit 351 can be a slit, is preferably line slit 351, thereby injects equably the 3rd rare gas element above the whole circumference of underfeed pipe 303.
In addition, preferably, the 3rd inertia gas column is along advancing towards the direction of the end of underfeed pipe 303 and with the excircle of underfeed pipe 303, and extend to molten steel M from the end, therefore, the 3rd inertia gas column makes the progress path of iron alloy F keep inert atmosphere with the first rare gas element and the second rare gas element of spraying from the inboard of the end of underfeed pipe 303.
In order to inject the 3rd rare gas element, keep simultaneously injecting the surface that shape arrives molten steel M, preferably, the width of slit 351 is below 3.0mm.
When the width of slit 351 surpassed 3.0mm, by continuous theorem, flow velocity was slack-off, and therefore, the 3rd rare gas element can disperse before the surface that arrives molten steel M.
When the width of slit 351 when 0.1mm is following, cause following problem, that is, can not disperse flowing of q.s, perhaps flow velocity is too fast, causes the mobile of the 3rd rare gas element to stop up.Therefore, the preferred width of slit 351 is extremely less than or equal to 3.0mm more than or equal to 0.1mm.
Fig. 9 is the general movement concept figure of according to an embodiment of the invention ferro-alloy inserting apparatus.
With reference to Fig. 9, iron alloy F enters in the top supply-pipe 301, thereby is fed among the molten steel M by middle part supply-pipe 302 and underfeed pipe 303.
When iron alloy F passed middle part supply-pipe 302, the first rare gas element blocks air and the iron alloy F that disperse by rare gas element blocking unit 323 flowed into (IG1) simultaneously.
The first rare gas element can be the 8th family's gas or nitrogen such as Ar, more preferably, considers possibility and the manufacturing cost of inhaling nitrogen, and the first rare gas element can be Ar.In addition, in the situation that the austenite steel grade can use nitrogen.
When iron alloy F passed underfeed pipe 303, the surface of the feeding path that the second rare gas element of supplying with by rare gas element feed unit 333 makes iron alloy F from the matrix end of underfeed pipe 303 to molten steel M kept inert atmosphere (IG2).
The second rare gas element can be the 8th family's gas, more preferably can be Ar.Be in the 300 serial austenitic situations at steel grade, also can use N
2
In addition, the 3rd rare gas element disperses by the outside, end of complex loop structure 350 from underfeed pipe 303, disperses to prevent the second rare gas element, and then keeps the feeding path of iron alloy F to be in inert atmosphere (IG3).
The 3rd rare gas element can be the 8th family's gas, preferably can be Ar.In addition, because the 3rd rare gas element is so that flow (IG2) of the second rare gas element that sprays from the inboard of underfeed pipe 303 remains in its outside, so preferably, the flow velocity of velocity ratio second rare gas element of the 3rd rare gas element is fast, perhaps, the injection pressure of the 3rd rare gas element is larger than the injection pressure of the second rare gas element.
Figure 10 is the diagram that the flow velocity to the circumference of the underfeed pipe in one embodiment of the invention and in another embodiment of the present invention compares.
As in (a), with respect to the circumference of underfeed pipe 103, along with flow velocity advances to the side (180 °) relative with this side (0 °) from the side (0 °) that the 3rd rare gas element feed unit 154 is installed, flow velocity significantly reduces.This is because inject the 3rd rare gas element, but in fact, the 3rd rare gas element that utilizes single ring architecture 150 to supply with is distributed in the circumferential direction of the circle.
Yet, in another embodiment of the present invention, as in (b), circumference with respect to underfeed pipe 303, along with flow velocity advances to the side (180 °) relative with this side (0 °) from the side (0 °) that the 3rd rare gas element feed unit 354 is installed, can make flow velocity more even.Different from the single ring architecture 150 of an embodiment, in the complex loop structure 350 of another embodiment, realized the even distribution in the circumferential direction of the circle of the 3rd rare gas element.
Be that 50% situation (a) is compared with the Nonuniform Domain Simulation of Reservoir of flow velocity with respect to whole zone, under situation (b), flow velocity is uniform generally.
According to the precision of the required velocity flow profile of technique, in technical scope disclosed by the invention, complex loop structure 350 can comprise a plurality of ring structures.That is, except the complex loop structure 350 by first ring structure 355 and the second ring structure 353 structures, can adopt the ring structure number is the complex loop structure of natural number (for example, tricyclic structure, Fourth Ring structure etc.).
As in technical scope, the 3rd rare gas element feed unit can also be communicated with plural complex loop structure 350, thus distribute traffic equably in the circumferential direction of the circle, as mentioned above.Yet, even in this case, still may have the ununiformity of flow velocity.
Hereinafter, the equipment that feeds according to the preferred embodiment of the invention iron alloy is described with reference to the accompanying drawings.
Figure 11 is the schematic diagram that according to the preferred embodiment of the invention oxygen uptake is shown and inhales the ferro-alloy inserting apparatus of nitrogen minimizing.
With reference to Figure 11, to be used for the temperature of casting and the target of composition in order in the ladle refining platform, realizing, refrigerant and iron alloy F to be weighed, and be fed in the ladle 22 that is soaked with molten steel M, wherein, the decarburization of molten steel M is finished in the decarburization container such as AOD, VOD and converter.
Utilize conveying belt 2 that iron alloy F is stored in the hopper 3 from iron alloy storage hopper 1, switch-valve 4 is configured for the feeding of control iron alloy F in the hopper 3 of storage iron alloy F.By supply-pipe 501,502 and 503 iron alloy F is fed into the molten steel M from hopper 3.
The ladle 22 of holding molten steel M comprises by stopping that atmosphere prevents oxidation and can feed the steel ladle cover 21 of iron alloy F, constructs supply-pipe 503 and supply-pipe 503 is immersed in the slag by penetrating steel ladle cover 21.
In a preferred embodiment of the invention, supply-pipe 501,502 and 503 is subdivided into top supply-pipe 501, middle part supply-pipe 502 and underfeed pipe 503, according to the position of hopper 3 and shop equipment, middle part supply-pipe 502 can tilt, as shown in drawings.
On any one zone of middle part supply-pipe 502, branch also is equipped with the rare gas element blocking unit 523 that comprises the first rare gas element feed unit 524, therefore, when supplying with iron alloy F from hopper 3, the feeding path of iron alloy F can be by stopping that comprising oxygen and nitrogen flows at interior air and keep inert atmosphere.
With reference to Figure 12, with rare gas element blocking unit 523 branches and be mounted to respect to the matrix end of middle part supply-pipe 502 and form more than 90 ° to the angle θ below 180 °
1Thereby rare gas element injects along the direction of the opposite direction that carries out with the feeding of iron alloy F, and being used for effectively, blocks air flows into.
By the rare gas element such as Ar that porous plug the last 23 from be installed in advance ladle 22 bottoms blown, iron alloy F removes a part of slag S in the molten steel top, in order to drop on swimmingly the position that will be spray eye.
At this moment, the composition of molten steel M is expressed as follows with % by weight: C:0 to 0.05%, N:0 to 0.070%, Si:p to 4%, Ti:0 to 0.5%, S: be lower than 0.030%, P: be lower than 0.025%, Cr:11.0% to 30.0%, Ni:0 to 36%.Molten steel M can be the stainless molten steel that is grouped into by other one-tenth, for example, and AISI benchmark 304,316L, 430,446 and 447 stainless steels.Can use through iron alloy and feed other steel of processing as molten steel M.
For iron alloy F is fed among the molten steel M, the feeding hole of underfeed pipe 503 drops to the surface of molten steel M by length control unit 513 and is not immersed in slag and the molten steel.
The length control unit 513 that is not immersed in slag and the molten steel can be the member that can control length usually, preferably, length control unit 513 is configured to make the end lifting that is positioned at the underfeed pipe 503 directly over the ladle 22, i.e. lifting feeding hole only.
Supply-pipe, more particularly, the end of middle part supply-pipe 502 and/or the matrix end of underfeed pipe 503, be communicated with the rare gas element feed unit 533 that comprises the second rare gas element feed unit 534, therefore, when feeding iron alloy F, the inert gas atmosphere that produces arrives the end of underfeed pipe 503.
Rare gas element feed unit 533 blows the second rare gas element of supplying with from the second rare gas element feed unit 534, so that the second rare gas element sprays from the end of underfeed pipe 503, therefore, when feeding iron alloy F, path at underfeed pipe 503 produces inert atmosphere, when the second rare gas element sprayed from the end of underfeed pipe 503, inert atmosphere was retained the surface that arrives molten steel.
The outside of underfeed pipe 503, more particularly, the circumference of the cylindrical lower part supply-pipe 503 of hollow is provided with single ring architecture 550, single ring architecture 550 and underfeed pipe 503 cavities formed co-axial are with parcel underfeed pipe 503, and single ring architecture 550 comprises the 3rd rare gas element feed unit 554.
Rare gas element injects unit 550 by utilizing the 3rd rare gas element parcel underfeed pipe 503 of supplying with from the 3rd rare gas element feed unit 554 to be injected into the end of underfeed pipe 503, namely along injecting towards the direction on the surface of molten steel M.
According to equipment, one or two or several the 3rd rare gas element feed unit 554 can be installed.
With reference to Figure 13 a and Figure 13 b, as described in an above embodiment and another embodiment, it can be single ring architecture 550 that rare gas element injects unit 550 " or complex loop structure 550 '.
Yet, as in above embodiment with reference to as described in Figure 10, preferably, rare gas element inject unit 550 be complex loop structure 550 '.
Injecting the 3rd rare gas element that injects unit 550 from rare gas element spreads from the end of underfeed pipe 503 by diffusion unit 570.
The shape of diffusion unit 570 is that the end from underfeed pipe 503 stretches out on the whole.In addition, the 3rd rare gas element that correspondingly stretches out.That is, the 3rd rare gas element passes through diffusion unit 570 to arrive the surface of molten steel M to the shape of external diffusion.At this moment, the 3rd rare gas element can be guaranteed wider exposed (naked eye) diameter by the zone of diffusion.
With reference to Figure 14, the spread angle θ that starts at from the inboard of underfeed pipe 503
2Be to below 90 ° more than 0 °.
More preferably, the inboard of underfeed pipe 503 and the shape in the outside become this spread angle or larger to the scope below 15 ° or 15 °, thereby meet spread angle θ described above
2
Figure 15 is the general movement concept figure that according to the preferred embodiment of the invention oxygen uptake is shown and inhales the ferro-alloy inserting apparatus of nitrogen minimizing.
At first, with reference to Figure 15, iron alloy F enters in the top supply-pipe 501, thereby is fed among the molten steel M by middle part supply-pipe 502 and underfeed pipe 503.
Before iron alloy F was by 501 feedings of top supply-pipe, underfeed pipe 503 dropped to the surface of molten steel M by length control unit (513 among Figure 11).
The end of underfeed pipe 503 drops to the distance predetermined apart from the surface of molten steel.Depend on the amount according to the molten steel M of technique change, the equation 1 below the decline of underfeed pipe 503 utilizes is so that the total surface that underfeed pipe 503 drops to apart from molten steel M is constant height.
[equation 1]
y＝h
0-x-c
Wherein, y is to the distance [mm] of the end of underfeed pipe 503 from the inboard of the lid 21 of ladle; h
0From the inboard of the lid 21 of ladle to the distance [mm] of the bottom of ladle, wherein, h
0It is fixed value; X is from the bottom of ladle 22 to the distance [mm] on the surface of molten steel, and wherein, x is the variable that the amount according to molten steel M changes; C is to the distance [mm] of the end of underfeed pipe 503 from the surface of molten steel.
At this moment, obtain x by following equation 2.
[equation 2]
w＝-51.1×ln(x)+454
(wherein, w is the amount of molten steel, and unit is ton)
Usually, be 3m or larger if be arranged to the end of underfeed pipe 503 from the distance on the surface of molten steel M, then the dropping distance of the iron alloy F of feeding is elongated, thereby produces a large amount of splashing.If be arranged to below 1m, then because near molten steel M, so cause underfeed pipe 503 that melting loss (melting loss) etc. occurs.Therefore, preferably, the distance from the end of underfeed pipe 503 to the surface of molten steel M is 1m to 3m.
Yet, can change according to the steel grade of employed molten steel M from the end of underfeed pipe 503 to the distance on the surface of molten steel M.
, then the first rare gas element is fed in the supply-pipe 502 of middle part to separate and the end of mobile underfeed pipe 503 at a distance of constant distance with the surface of molten steel M by length control unit 513.
When iron alloy F passes middle part supply-pipe 502, inject the first rare gas element by rare gas element blocking unit 523, thereby blocks air and iron alloy F (IG1) enter simultaneously in the supply-pipe 502 of middle part.
The first rare gas element can be the 8th family's gas or nitrogen such as Ar, more preferably, considers possibility and the manufacturing cost of inhaling nitrogen, and the first rare gas element can be Ar.In addition, in the situation that the austenite steel grade can use nitrogen.
When iron alloy F passed underfeed pipe 503, the second rare gas element of supplying with by rare gas element feed unit 533 made the surface from the matrix end of underfeed pipe 503 to molten steel M keep inert atmosphere (IG2).At this moment, can feed iron alloy F under the situation of guaranteeing wider exposed region by proliferation part 570, described wider exposed region arrives the surface of molten steel M.
The second rare gas element can for the 8th family's gas, more preferably can be Ar.Be in the 300 serial austenitic situations at steel grade, also can use nitrogen.
In addition, in the outside of the end of underfeed pipe 503, pass the 3rd rare gas element that rare gas element injects unit 550 by proliferation part 570 to inject to the shape of external diffusion, thereby prevent that the second rare gas element from disperseing, so that the feeding Route maintenance of iron alloy is at inert atmosphere (IG3).
The 3rd rare gas element can for the 8th family's gas, more preferably can be Ar.In addition, because the 3rd rare gas element is so that flow (IG2) of the second rare gas element that sprays from the inboard of underfeed pipe 503 remains in its outside, so preferably, the flow velocity of velocity ratio second rare gas element of the 3rd rare gas element is fast, perhaps, the injection pressure of the 3rd rare gas element is larger than the injection pressure of the second rare gas element.
At this moment, preferably, the injection rate of the time per unit of the second rare gas element can be 5-50Nm
3/ hr.If injection rate is less than 5Nm
3/ hr does not then form enough inert atmospheres, thereby owing to airborne oxygen and nitrogen produce oxygen uptake and inhales nitrogen, if injection rate surpasses 50Nm
3/ hr, then the gas column of the 3rd rare gas element is destroyed, thereby disperses owing to the sidepiece diffusion makes the second rare gas element, perhaps causes process costs to increase owing to having supplied with second rare gas element of Duoing than aequum.
In addition, preferably, the injection rate of the time per unit of the 3rd rare gas element can be 10-100Nm
3/ hr.If injection rate is less than 10Nm
3/ hr, then the sidepiece diffusion owing to the second rare gas element produces dispersion, thereby makes the inert atmosphere variation, if injection rate surpasses 100Nm
3/ hr has then supplied with the 3rd rare gas element of Duoing than aequum.Therefore, preferably, be 100Nm with the controlling of injecting quantity
3/ hr or less.
By utilizing the first rare gas element, the second rare gas element and the 3rd rare gas element after the feeding path of iron alloy F produces inert atmosphere, utilize the porous plug 23 that in the bottom of ladle 22, is communicated with rare gas element supply-pipe 24 to blow the 4th rare gas element.
The 4th rare gas element rises to the upper surface of molten steel from the bottom of ladle 22 with bubble form, thereby exposed by Bubble formation.
If spray eye reaches the steady state that is stabilized to a certain degree by the Bubble formation of the 4th rare gas element, that is, if determine that the generation degree of spray eye is continuous, then open switch-valve 4, thus the iron alloy F that feeding is held in storage hopper 3.
As mentioned above, because the regional A by the inert atmosphere of the mobile generation of the second rare gas element and the 3rd rare gas element is enough to open produce on the surface of molten steel M exposed, so can in inert atmosphere, iron alloy F be fed into molten steel M from hopper, minimize thereby make oxygen uptake and inhale nitrogen.
Hereinafter, will be described in 409 stainless steels and the 336L stainless steel that melts in 90 tons the electric furnace by example.
Table 1 shows the oxygen nitrogen in the molten steel under two kinds of situations is changed the data that compare, wherein, a kind of situation is to utilize traditional iron alloy feeding method, and another kind of situation is: after AOD decarburization container flows out 409 stainless steels and 436L stainless steel, utilize the iron alloy injection device shown in Fig. 2 that 409 stainless steels and 436L stainless steel are fed in the ladle in the Ladle Treatment platform.At this moment, in the ladle feed quantity of iron alloy 0.5 ton/heat to 2 tons/heat scope in.
Table 1
Such as table 1 and shown in Figure 16, in the situation that conventional example (grade of steel: 1 to 4), oxygen partial pressure under atmospheric condition is under the condition of 0.185atm, the increasing amount of nitrogen (Δ N) is from 8ppm to 18ppm, yet, (grade of steel: 5 to 9), the increasing amount of nitrogen (Δ N) significantly reduces to 1ppm to 4ppm in situation of the present invention.
In other words, as shown in figure 16, in the situation of 1 to No. 4 steel of conventional example, before and after the iron alloy feeding was processed in ladle, the nitrogen concentration in the molten steel changed to 66ppm, changes to 87ppm, changes to 94ppm, changes to 97ppm from 79ppm from 80ppm from 75ppm from 58ppm respectively.Therefore as can be known, the nitrogen concentration before the nitrogen concentration after the iron alloy feeding is processed is processed than the iron alloy feeding has on average increased 13ppm significantly.This means and in iron alloy feeding process, produce molten steel from the suction nitrogen of atmosphere.
Yet, (grade of steel: 5 to 9) in situation of the present invention, before and after the iron alloy feeding is processed, nitrogen concentration increase in the molten steel significantly decreased average to 2ppm, for example from 68ppm to 72ppm, from 53ppm to 54ppm, from 73ppm to 75ppm, from 70ppm to 72ppm and from 67ppm to 68ppm.
Therefore as can be known, in iron alloy feeding process, reduced significantly molten steel from atmospheric absorption nitrogen.
Simultaneously, consider the variation of oxygen, such as table 1 and shown in Figure 17, in the situation that conventional example (grade of steel: 1 to 4), the oxygen partial pressure under atmospheric condition is under the condition of 0.185atm, and the increasing amount of oxygen is from 0ppm to 37ppm, yet, (grade of steel: 5 to 9), except No. 8 steel, oxygen concn has reduced 7ppm to 24ppm significantly in situation of the present invention.
That is, be appreciated that from Figure 17 and process before and after the iron alloy in ladle in the situation of 1 to No. 4 steel of conventional example, oxygen concn changes to 110ppm, changes to 91ppm, changes to 110ppm, changes to 110ppm from 92ppm from 91ppm from 91ppm from 73ppm respectively.Therefore as can be known, the oxygen concn before the oxygen concn after the iron alloy feeding is processed is processed than the iron alloy feeding has on average increased 18.5ppm significantly.This means in iron alloy feeding process reoxidizing of molten steel occured.
But, (grade of steel: 5 to 9), the oxygen concn of the molten steel before and after iron alloy is processed changes to 70ppm, changes to 51ppm, changes to 66ppm, changes to 110ppm and change to 90ppm from 97ppm from 92ppm from 86ppm from 75ppm from 91ppm respectively in situation of the present invention.Therefore as can be known, the oxygen concn decreased average 10.8ppm.
That is, this means, in situation of the present invention, when the feeding iron alloy, reduced significantly reoxidizing of molten steel.
In Figure 18, suitably show this reason.Figure 18 shows that oxygen concn is over time during iron alloy in feeding.Utilize measuring unit 203 to measure the variation of nitrogen and oxygen by following steps: to gather gas by means of underfeed pipe 503 any one point on the path on the surface from vent fan 201 to molten steel M; Utilize the gas of 202 pairs of collections of dividing potential drop survey sensor to measure.
As shown in figure 18, in the situation that conventional example, in conventional example, the oxygen partial pressure between feeding pipe and molten steel surface is under the condition of about 0.185atm (18.5%),, for being easy under the condition, carries out the iron alloy feeding at atmospheric oxidn that is.
Yet, in situation of the present invention, because be under the condition of about 0.02atm to 0.0002atm (2% to 0.02%) in oxygen partial pressure, namely under oxygen partial pressure is low condition, carry out the iron alloy feeding, so can infer and reoxidizing of less generation molten steel.
Figure 19 is the diagram that illustrates through the comparative example of the ratio of defects of lip-deep oxide compound (steel-making) inclusion of the stainless steel hot-rolling volume of the Ladle Treatment technique of conventional example and example of the present invention.
As shown in figure 19, in conventional example, in the situation that 1 to No. 4 steel, the lamination rate is average 3.4%, for example is respectively 4.8%, 1.5%, 3.9%, 3.3%; Yet in the situation that 5 to No. 9 steel, the lamination rate is decreased average to 1.7% significantly, for example is respectively 1.5%, 0.8%, 1.3%, 3.7% and 1.3%.
This result is because improved the degree of cleaning of molten steel.Hence one can see that, and the surface quality of product significantly improves.
Although illustrated and described some embodiments of the present invention, it will be appreciated by those skilled in the art that, in the situation that does not break away from principle of the present invention that scope limits by claim and equivalent thereof and spirit, can make a change in an embodiment.
Claims (7)
1. an oxygen uptake and inhale the ferro-alloy inserting apparatus that nitrogen reduces comprises:
Supply-pipe, supply with iron alloy from hopper to described supply-pipe, thereby described iron alloy is fed in the ladle, and need not described supply-pipe is immersed in slag and the molten steel, described supply-pipe is subdivided into middle part supply-pipe, the underfeed pipe of top supply-pipe, inclination, and has predetermined hollow;
Branch and the rare gas element blocking unit of installing are communicated with the middle part supply-pipe of described supply-pipe, and when the described iron alloy of feeding, described rare gas element blocking unit flows into simultaneously with the first rare gas element blocks air;
Branch and the rare gas element feed unit of installing are communicated with the upper end of the underfeed pipe of described supply-pipe, and blow the second rare gas element in the feeding path of described iron alloy;
Rare gas element injects the unit, with respect to the direction of principal axis of the underfeed pipe of described supply-pipe, and the underfeed pipe outside of wrapping up described supply-pipe, and inject the 3rd rare gas element towards the bottom of the underfeed pipe of described supply-pipe;
Diffusion unit diffuses through described rare gas element from the end of described underfeed pipe and injects the 3rd rare gas element that the unit injects, and described the 3rd rare gas element wraps up described underfeed pipe simultaneously.
2. oxygen uptake as claimed in claim 1 and the ferro-alloy inserting apparatus of inhaling the nitrogen minimizing, wherein, it is the complex loop structure that described rare gas element injects the unit, described complex loop structure is made of first ring structure, the second ring structure and a plurality of junctor, described first ring structure distributes described the 3rd rare gas element equably, described the second ring structure wraps up described underfeed Guan Bingxiang end direction and is infused in equally distributed the 3rd rare gas element in the described first ring structure, and described a plurality of junctors are communicated with described first ring structure with described the second ring structure.
3. oxygen uptake as claimed in claim 2 and the ferro-alloy inserting apparatus of inhaling the nitrogen minimizing, wherein, described rare gas element injection unit is formed with predetermined slit along the end of described underfeed pipe.
4. oxygen uptake as claimed in claim 3 and inhale the ferro-alloy inserting apparatus that nitrogen reduces, wherein, the width of described slit is 3.0mm or less than 3.0mm.
5. oxygen uptake as claimed in claim 4 and the ferro-alloy inserting apparatus of inhaling the nitrogen minimizing, wherein, the width of described slit is extremely less than or equal to 3.0mm more than or equal to 0.1mm.
6. oxygen uptake as claimed in claim 1 and the ferro-alloy inserting apparatus of inhaling the nitrogen minimizing, wherein, the internal divergence angle between the inside of the inside of described diffusion unit and described underfeed pipe is extremely less than 90 ° greater than 0 °.
7. iron alloy feeding method that uses oxygen uptake as claimed in claim 1 and inhale the ferro-alloy inserting apparatus that nitrogen reduces, in ladle, hold the molten steel that is covered by slag, the iron alloy that will be stored in the hopper by top supply-pipe, middle part supply-pipe and underfeed pipe is fed into the described molten steel from the top of described ladle, in the bottom of described ladle, porous plug is installed, said method comprising the steps of:
The end of described underfeed pipe is descended;
The first rare gas element is fed in the supply-pipe of described middle part;
The second rare gas element is fed in the matrix end of described underfeed pipe;
By wrapping up the outside of described underfeed pipe, provide the 3rd rare gas element that injects along end direction;
Successively described iron alloy is fed into described top supply-pipe, described middle part supply-pipe and described underfeed pipe,
Wherein, the injection rate of the time per unit of described the second rare gas element is 5Nm
3/ hr to 50Nm
3/ hr, the injection rate of the time per unit of described the 3rd rare gas element is 10Nm
3/ hr to 100Nm
3/ hr.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2006-0079692 | 2006-08-23 | ||
| KR1020060079693A KR100812018B1 (en) | 2006-08-23 | 2006-08-23 | Apparatus with spreading part for inserting ferro-alloy |
| KR1020060079693 | 2006-08-23 | ||
| KR1020060079692A KR100812017B1 (en) | 2006-08-23 | 2006-08-23 | Method for laddle treatment |
| KR1020060079692 | 2006-08-23 | ||
| KR10-2006-0079693 | 2006-08-23 | ||
| PCT/KR2006/005406 WO2008023863A1 (en) | 2006-08-23 | 2006-12-12 | A ferro-alloy inserting apparatus with reduced absorption of oxygen and absorption of nitrogen and inserting method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101541982A CN101541982A (en) | 2009-09-23 |
| CN101541982B true CN101541982B (en) | 2013-01-02 |
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|---|---|---|---|
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| KR101249132B1 (en) | 2011-08-01 | 2013-04-02 | 주식회사 포스코 | Apparatus for preventing absorption of nitrogen stainless steel |
| CN105219917B (en) * | 2014-06-11 | 2018-02-27 | 鞍钢股份有限公司 | Alloy Adding Device and Method for Non-vacuum Induction Furnace |
| KR101641778B1 (en) * | 2014-10-10 | 2016-07-22 | 주식회사 포스코 | Refining medium-high carbon steel method for preventing corner crack |
| KR101853769B1 (en) | 2016-08-29 | 2018-05-02 | 주식회사 포스코 | Manufacturing method of alloy steel |
| CN108285947B (en) * | 2017-02-28 | 2019-09-27 | 安徽工业大学 | A kind of molten steel alloyage process in protection tapping process |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5919283A (en) * | 1996-11-06 | 1999-07-06 | Premelt Pump, Inc. | Method and apparatus for introducing metal chips into molten metal bath |
| US6136064A (en) * | 1994-12-15 | 2000-10-24 | Hayes Lemmerz International, Inc. | Method for charging a reverbratory furnace with metal chips |
| US6409962B1 (en) * | 2000-10-02 | 2002-06-25 | Rossborough Manufacturing Co. | Powder injector for ladle |
| JP2005002369A (en) * | 2003-06-09 | 2005-01-06 | Sumitomo Metal Ind Ltd | Apparatus for refining molten steel |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02221315A (en) * | 1989-02-21 | 1990-09-04 | Nkk Corp | Method for tapping molten steel in converter and apparatus for preventing outer air suction in steel tapping hole |
| JPH0641615B2 (en) * | 1989-10-27 | 1994-06-01 | 新日本製鐵株式会社 | Auxiliary raw material charging device for pressure converter |
| JPH06212240A (en) * | 1993-01-13 | 1994-08-02 | Shinagawa Refract Co Ltd | Method for preventing absorption of nitrogen in vacuum degassing treatment |
| JPH07138630A (en) * | 1993-11-15 | 1995-05-30 | Kawasaki Steel Corp | Device for charging powdery and granular material in metal refining furnace and charging lance |
| JPH08311530A (en) * | 1995-05-16 | 1996-11-26 | Nkk Corp | Degassing refining method |
| KR100698755B1 (en) | 2005-12-23 | 2007-03-23 | 주식회사 포스코 | Apparatus for inserting ferro-alloy |
| KR101249201B1 (en) * | 2005-12-23 | 2013-04-02 | 주식회사 포스코 | Method for laddle treatment |
-
2006
- 2006-08-23 KR KR1020060079692A patent/KR100812017B1/en active IP Right Grant
- 2006-12-12 CN CN2006800556590A patent/CN101541982B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6136064A (en) * | 1994-12-15 | 2000-10-24 | Hayes Lemmerz International, Inc. | Method for charging a reverbratory furnace with metal chips |
| US5919283A (en) * | 1996-11-06 | 1999-07-06 | Premelt Pump, Inc. | Method and apparatus for introducing metal chips into molten metal bath |
| US6409962B1 (en) * | 2000-10-02 | 2002-06-25 | Rossborough Manufacturing Co. | Powder injector for ladle |
| JP2005002369A (en) * | 2003-06-09 | 2005-01-06 | Sumitomo Metal Ind Ltd | Apparatus for refining molten steel |
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| KR100812017B1 (en) | 2008-03-10 |
| KR20080017892A (en) | 2008-02-27 |
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