CN102719724A - Method for improving and stabilizing boron yield in smelting boron-containing steel - Google Patents
Method for improving and stabilizing boron yield in smelting boron-containing steel Download PDFInfo
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Abstract
The invention provides a method for improving and stabilizing a boron yield in smelting boron-containing steel. The method adopts a converter-LF furnace-continuous casting process, and is characterized in that in slag after a LF furnace refining, an amount of FeO and MnO is less than or equal to 1.5%, the amount of T[O] is less than or equal to 0.0030%, and the amount of N is less than or equal to 0.0040%. The continuous casting applies a full protection casting. A boron-containing powder is injected into molten steel through a drilling way of a ladle elongated nozzle using an inert gas Ar as a carrier gas when the molten steel is injected in a tundish. The method is low in production cost and simple in operation process without VD furnace treatment and with no need of adding Ti for nitrogen fixation treatment. The boron-containing steel produced by the method has a boron yield of 70%- 90% and the difference of the boron yield of each batch is less than 0.0003 %, which are far better than those of a conventional smelting method for the boron-containing steel.
Description
Technical field
The invention belongs to technical field of ferrous metallurgy, particularly a kind of method that improves and stablize boron yield when smelting boron-containing steel.
Background technology
In the alloying element of in high-strength low alloy steel, being paid close attention to, it is more special a kind of that boron is considered to.Can improve hardening capacity on the basis of the inherent assurance of addition 0.001%～0.003% scope of boron matrix; And its hardening capacity is not second to containing 0.6%Mn; 0.7%Cr, the steel grade of 0.5%Mo and 1.5%Ni, therefore; The hundred times that its ability that improves hardening capacity is above-mentioned alloying element and even thousands of times are so only need minute quantity boron can practice thrift a large amount of valuable alloying elements.The effect that general alloying element improves hardening capacity increases with its content in steel; But boron has an optimum content (scope), and is too much or very few all unfavorable to improving hardening capacity, and this amount is very little; Be about 0.0010%, generally be controlled at 0.0005%～0.0030%.
Because the chemical property of boron is very active; Be easy to steel in oxygen, nitrogen combine; Make boron ineffective, and the boron content in the steel is few again, so how to guarantee in the smelting of boron steel stably to obtain that an amount of acid dissolves boron and be evenly distributed in the steel is very important.The technology of tradition smelting boron steel: converter-LF stove-continuous casting or converter-LF stove-VD stove-continuous casting; In the steel-making later stage (LF stove or VD stove); Through adding the abundant deoxidation of aluminium, add the abundant fixed nitrogen of iron alloy such as titanium, zirconium, add ferro-boron afterwards again; The adding mode of boron has two kinds: the one, add with the ferro-boron form, and another kind is to add with the cored-wire form.Traditional smelting process is very strict to each processing requirement, and the distribution in steel of the yield of boron, boron is also unstable.Be different from above-mentioned traditional smelting technology method, Chinese patent 200810015497.9 has been reported before the molten steel vacuum-treat and carry out boron alloyization, the vacuum-treat post analysis, and the boron recovery is more than 90%, and the boron content deviation is less than 0.0002% between each stove.Though this technology can be stabilized and increased the yield of boron, slag composition has been carried out strict restriction: (%FeO)+(%MnO)＜1.50%, (%Si0
2)＜15.00% in addition, consumes iron alloys such as a large amount of titaniums, zirconium equally, to reduce oxygen, the nitrogen content in the molten steel, prevents the boron over oxidation.Chinese patent 200410050358.1 has reported with the boracic molten iron to be the method for the direct smelting boron steel of raw material, and the boracic molten iron is to adopt blast furnace to separate paigeite to extract B
2O
3The time a kind of natural boracic metallic product that obtains.But, because silicon and sulphur content are very high in the boracic molten iron, be respectively 2.0%～2.5% and 0.06%～0.1%, so the quantity of slag that causes producing in the steelmaking process is big, make the production cost increase, in addition, boron is with B
2O
3Form exists, and in steelmaking process, will float and to slag, remove, and has reduced the yield of boron.Relevant document has been introduced the recovery situation of smelting boron-containing steel boron: in the Chinese patent 200710049005.3, can make the recovery of boron reach 69.4%～91.8% in the method for the converter smelting boron-containing steel of introduction.Introduced in 2009 the 1st phases of document " casting " " analysis of Influential Factors of the r recovery in the High Boron Steel " and adopted two kinds of technologies to smelt boron-containing steel: vacuum and antivacuum processing; The boron yield is 78%～96.7%, but need add the recovery that alloys such as Ti, Zr and rare earth are stablized boron simultaneously.Introduce the application traditional technology in 1992 the 5th phases of document " special steel " " metallurgy factor is to the influence of the B recovery in the boron steel " and smelted boron-containing steel; Adopt the alloy of deoxidation fixed nitrogen to add mode; Its optimum content should be controlled at Al:0.02%～0.05%; Ti:0.03%～0.05%, addition sequence are Al-Ti-B, and this kind technology can make the recovery of boron reach 10%～65%.Be employed in LF stove refining later stage feeding B heart yearn mode in 1997 the 2nd phases of document " special steel " " Application and Development of 60t ladle furnace line feeding technology " and add boron, can make the boron recovery reach 85%.Though adopt the line feeding mode can improve the recovery of boron in steel, relatively stricter to the specification of quality of cored-wire, its cost is also bigger equally.
Therefore it is very important how when reducing iron alloy deoxidation fixed nitrogen such as aluminium, titanium, zirconium, calcium, guaranteeing stably to obtain the molten boron of an amount of acid in smelting again and being evenly distributed in the steel.Like this, not only improved the yield of boron but also can reduce production costs.
Summary of the invention
It is not enough to the objective of the invention is to overcome above-mentioned existing in prior technology, provides a kind of and can reduce the consumption of deoxidation fixed nitrogen alloy and reduce the boron-containing steel smelting cost, the method for raising and stable boron yield.
The operational path that the present invention adopts is: converter-LF stove-continuous casting, need be through vacuum-treat, and concrete process step is following:
1) smelting molten steel: adopt converter and LF stove smelting molten steel; Deoxidation of molten steel technology all adopts known smelting technology, uses the most frequently used Al, Ca, Si etc. and gets final product as reductor, need not add the Ti alloy and carry out the fixed nitrogen processing; After the refining of LF stove finishes; Guarantee (FeO+MnO)≤1.5% in the slag, T [O]≤0.0030%, N≤0.0040%.
2) molten steel after refining finishes is transported to continuous casting, adopts the whole process protection casting, and when molten steel injected tundish, the mode of holing through ladle long nozzle was that carrier gas sprays into the boracic pulvis in the molten steel with rare gas element Ar gas.
Boracic pulvis of the present invention is B
4C or B
4C+Fe-B or B
4C+B, its granularity is 500～50 μ m, surpasses yield and stability that this scope will influence boron, also is prone to cause the line clogging phenomenon, its winding-up amount is decided according to the boron-containing quantity of steel grade; The jetting pressure of said Ar gas is 0.35～0.40Mpa, and gas flow is 1.5～2.0m
3/ h, the winding-up time is the pouring time of every jar of molten steel; Said ladle long nozzle bore position is 200～300mm apart from the long nozzle upper end, and the quantity in hole is 1, and the axial and long nozzle in hole axially is 10～45 ° of angles, is connected with source of the gas with powder spraying apparatus through metallic hose.The conveying of pulvis of the present invention is not limited to this kind mode, also can adopt modes such as spray gun conveying.
The present invention sprays into the boracic pulvis in the tundish molten steel in every jar of molten steel casting, mainly is to utilize the stirring of molten steel here to make the fully contact with it of boracic pulvis, makes homogenization of composition, helps improving the stability and the yield of boron.
The present invention only adopts converter-LF stove-continuous casting smelting technology route, handles without the VD stove, need not add Ti simultaneously and carry out the fixed nitrogen processing, can practice thrift the mass production cost like this.The boron-containing steel that adopts the present invention to produce, boron has advantages of higher stability and yield, and the boron yield is 70%～90%; The boron yield differs less than 0.0003% between each jar time, and present method or all will be far superior to traditional boron smelting technology method no matter from production cost on boron yield and the stability; And raw material is prone to produce; Price is low, and operating procedure is simple, has good application prospects.
Embodiment
Through embodiment the present invention is done further description below.
Embodiment 1
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 4 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0025%, N≤0.0035%, (FeO+MnO)=1.2% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects single pulvis B for use
4(purity: 95.2%) as blowing powder, powder granularity 300 μ m, argon gas are as carrier gas, blowing gas pressure 0.35Mpa, gas flow 1.5m for C
3/ h, B
4C pulvis add-on 2.8kg, smelting molten steel weight 102t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0022%, through calculating boron yield 84.1%, all the other 3 jars of steel boron yields are respectively 81.7%, 86.2% and 85.6%.
Single B jets
4The C pulvis is compared with former technology (adopting the Fe-B alloy form), and 1～2 yuan/village steel can save production cost.And do not need also can practice thrift the large number quipments running expense through vacuum-treat.
Embodiment 2
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0028%, N≤0.0037%, (FeO+MnO)=1.38% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects single pulvis B for use
4(purity: 95.2%) as blowing powder, powder granularity 200 μ m, argon gas are as carrier gas, blowing gas pressure 0.38Mpa, gas flow 1.7m for C
3/ h, B
4C pulvis add-on 2.5kg, smelting molten steel weight 98t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0021%, through calculating boron yield 85.4%, all the other 2 jars of steel boron yields are respectively 86.8% and 82.6%.
Embodiment 3
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0022%, N≤0.0033%, (FeO+MnO)=1.42% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects single pulvis B for use
4(purity: 95.2%) as blowing powder, powder granularity 100 μ m, argon gas are as carrier gas, blowing gas pressure 0.40Mpa, gas flow 2.0m for C
3/ h, B
4C pulvis add-on 2.5kg, smelting molten steel weight 100t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0023%, through calculating boron yield 87.7%, all the other 2 jars of steel boron yields are respectively 84.8% and 86.6%.
Embodiment 4
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0020%, N≤0.0037%, (FeO+MnO)=1.22% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects B for use
4C+Fe-B (weight percent: B
4C:50%, Fe-B:50%) (B
4C purity: 95.2%, B content among the Fe-B: 18.5%) as blowing powder, powder granularity 100 μ m, argon gas are as carrier gas, blowing gas pressure 0.35Mpa, gas flow 1.8m
3/ h, pulvis add-on 5.2kg, smelting molten steel weight 105t, molten steel boron content 0.0003% before the winding-up, winding-up back boron content 0.0020%, through calculating boron yield 73.4%, all the other 2 jars of steel boron yields are respectively 70.6% and 72.4%.
Embodiment 5
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0022%, N≤0.0034%, (FeO+MnO)=1.14% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects B for use
4C+Fe-B (weight percent: B
4C:55%, Fe-B:45%) (B
4C purity: 95.2%, B content among the Fe-B: 18.5%) as blowing powder, powder granularity 75 μ m, argon gas are as carrier gas, blowing gas pressure 0.38Mpa, gas flow 1.8m
3/ h, pulvis add-on 5.6kg, smelting molten steel weight 104t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0024%, through calculating boron yield 79.4%, all the other 2 jars of steel boron yields are respectively 77.6% and 76.4%.
Embodiment 6
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0028%, N≤0.0039%, (FeO+MnO)=1.446% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects B for use
4C+Fe-B (weight percent: B
4C:53%, Fe-B:47%) (B
4C purity: 95.2%, B content among the Fe-B: 18.5%) as blowing powder, powder granularity 75 μ m, argon gas are as carrier gas, blowing gas pressure 0.40Mpa, gas flow 2.0m
3/ h, pulvis add-on 5.5kg, smelting molten steel weight 101t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0022%, through calculating boron yield 69.4%, all the other 2 jars of steel boron yields are respectively 70.8% and 72.7%.
Embodiment 7
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0026%, N≤0.0033%, (FeO+MnO)=1.42% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects B for use
4C+B (weight percent: B
4C:50%, B:50%) (B
4C purity: 95.2%, B purity: 99.5%) compound powder is as blowing powder, and powder granularity 75 μ m, argon gas are as carrier gas, blowing gas pressure 0.35Mpa, gas flow 1.8m
3/ h, compound powder add-on 3.3kg, smelting molten steel weight 102t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0024%, through calculating boron yield 71.4%, all the other 2 jars of steel boron yields are respectively 74.5% and 70.7%.
Embodiment 8
The smelting boron-containing quantity is 0.0005%～0.0030% steel for engineering mechanism purpose, originally waters the inferior 3 jars of boron-containing steels of producing altogether, uses present method to carry out boron alloyization and control boron content.
Molten steel need not add metal Ti and carry out fixed nitrogen processing, T [O]=0.0025%, N≤0.0035%, (FeO+MnO)=1.41% in the slag behind converter, LF stove deoxygenation refining.
Molten steel is transported to tundish and casts after the refining, selects B for use
4C+B (weight percent: B
4C:52%, B:48%) (B
4C purity: 95.2%, B purity: 99.5%) compound powder is as blowing powder, and powder granularity 75 μ m, argon gas are as carrier gas, blowing gas pressure 0.40Mpa, gas flow 2.0m
3/ h, compound powder add-on 2.5kg, smelting molten steel weight 103t, molten steel boron content 0.0004% before the winding-up, winding-up back boron content 0.0023%, through calculating boron yield 81.4%, all the other 2 jars of steel boron yields are respectively 84.3% and 80.9%.
Claims (4)
1. smelt the method that boron-containing steel improves and stablize the boron yield for one kind, adopt converter-LF stove-continuous casting production process, it is characterized in that the refining of LF stove finishes after, (FeO+MnO)≤1.5% in the slag, T [O]≤0.0030%, N≤0.0040%; When molten steel injected tundish, the mode of holing through ladle long nozzle was that carrier gas sprays into the boracic pulvis in the molten steel with rare gas element Ar gas, and above per-cent all is weight percentage.
2. the method for raising according to claim 1 and stable boron yield is characterized in that described boracic pulvis is B
4C or B
4C+Fe-B or B
4C+B, its granularity is 500～50 μ m, its winding-up amount is decided according to the boron-containing quantity of steel grade.
3. the method for raising according to claim 1 and stable boron yield, the jetting pressure that it is characterized in that said Ar gas is 0.35～0.40Mpa, gas flow is 1.5～2.0m
3/ h, the winding-up time is the pouring time of every jar of molten steel.
4. the method for raising according to claim 1 and stable boron yield, it is characterized in that said tundish long nozzle bore position apart from long nozzle upper end 200～300mm, the hole axially and long nozzle axially be 10～45 ° of angles.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102994700A (en) * | 2012-11-28 | 2013-03-27 | 武钢集团昆明钢铁股份有限公司 | Smelting method for stably increasing content of boron in boron-containing steel |
| CN107287490A (en) * | 2017-06-28 | 2017-10-24 | 江苏省沙钢钢铁研究院有限公司 | Improve the boron-containing steel smelting process method of boron recovery rate |
| CN107586917A (en) * | 2017-08-11 | 2018-01-16 | 舞阳钢铁有限责任公司 | Improve the smelting process of the molten boron ratio of acid in low-carbon quenching and tempering, high |
| CN108588541A (en) * | 2018-03-09 | 2018-09-28 | 江苏省沙钢钢铁研究院有限公司 | A kind of low nitrogen boron-containing steel smelting process improving boron element recovery rate |
| CN109234607A (en) * | 2018-10-26 | 2019-01-18 | 山东钢铁集团日照有限公司 | A kind of wide plate base production method improving the molten boron content of acid |
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| CN101736123A (en) * | 2010-01-08 | 2010-06-16 | 北京工业大学 | Boron-containing alloy smelting process with high yield |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102994700A (en) * | 2012-11-28 | 2013-03-27 | 武钢集团昆明钢铁股份有限公司 | Smelting method for stably increasing content of boron in boron-containing steel |
| CN107287490A (en) * | 2017-06-28 | 2017-10-24 | 江苏省沙钢钢铁研究院有限公司 | Improve the boron-containing steel smelting process method of boron recovery rate |
| CN107586917A (en) * | 2017-08-11 | 2018-01-16 | 舞阳钢铁有限责任公司 | Improve the smelting process of the molten boron ratio of acid in low-carbon quenching and tempering, high |
| CN108588541A (en) * | 2018-03-09 | 2018-09-28 | 江苏省沙钢钢铁研究院有限公司 | A kind of low nitrogen boron-containing steel smelting process improving boron element recovery rate |
| CN108588541B (en) * | 2018-03-09 | 2020-05-26 | 江苏省沙钢钢铁研究院有限公司 | Low-nitrogen boron-containing steel smelting method for improving boron element yield |
| CN109234607A (en) * | 2018-10-26 | 2019-01-18 | 山东钢铁集团日照有限公司 | A kind of wide plate base production method improving the molten boron content of acid |
| CN109234607B (en) * | 2018-10-26 | 2020-11-10 | 山东钢铁集团日照有限公司 | Wide slab production method for increasing acid-soluble boron content |
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