CN211689145U - Device for adding rare earth into molten steel - Google Patents
Device for adding rare earth into molten steel Download PDFInfo
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- CN211689145U CN211689145U CN201921762845.9U CN201921762845U CN211689145U CN 211689145 U CN211689145 U CN 211689145U CN 201921762845 U CN201921762845 U CN 201921762845U CN 211689145 U CN211689145 U CN 211689145U
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Abstract
The utility model belongs to the technical field of ferrous metallurgy, concretely relates to device to add tombarthite in molten steel. The device includes the support frame, sets up the lift rotary system in the upper end of support frame, and this lift rotary system is connected with the jetting pipe, and the one end of jetting pipe is the jetting pipe head, and the gas holder is connected to the other end of this jetting pipe, sets up gas flow pressure control system in the export of gas holder, is provided with the tombarthite feed bin on the jetting pipe between gas flow pressure control system and jetting pipe head, sets up feed arrangement between tombarthite feed bin and jetting pipe. The device is convenient to use, and the effect of adding tombarthite is good, and convenient operation is simple and easy effective.
Description
Technical Field
The utility model belongs to the technical field of ferrous metallurgy, concretely relates to device to add tombarthite in molten steel.
Background
Continuous casting, i.e., continuous casting of steel, is a molten steel forming technique in which refined molten steel is continuously fed into a mold, solidified and formed, and then drawn out from below the mold. Compared with the traditional die casting process, the continuous casting process is a great technical progress.
The addition of a proper amount of rare earth into steel has three main functions: purifying molten steel, modifying inclusion and microalloying, improving the toughness and plasticity, particularly the transverse impact toughness of the steel and improving the anisotropy of steel; for example, the rare earth can lead high-hardness alumina to be mixed and converted into spherical oxysulfide and rare earth aluminate, thereby obviously improving the fatigue resistance of the steel; the segregation of the rare earth in the grain boundary can inhibit the segregation of phosphorus and sulfur and low-melting-point impurities of lead, tin, arsenic, antimony and bismuth in the grain boundary or form compounds with higher melting points with the impurities, purify and strengthen the grain boundary, eliminate the harmful effect of the low-melting-point impurities, and be beneficial to improving plasticity, particularly high-temperature plasticity and the like. After the rare earth is applied to the steel, the effects of refining impurities, deeply purifying molten steel and strongly microalloying can be achieved, the toughness, plasticity and fatigue life of the steel are obviously improved, and the steel is more tough, heat-resistant, wear-resistant and corrosion-resistant.
When the rare earth is industrially applied to steel, two major bottleneck problems are not solved all the time: firstly, rare earth is added into molten steel to block a pouring system, and the continuous casting process is forced to be interrupted, so that the smooth process is seriously influenced; secondly, after the rare earth is added, large-size and high-density rare earth inclusions are easily formed, so that the performance of the steel is good, bad and unstable. The main reason is that no mature stable rare earth addition process has been formed. At present, a plurality of experimental researches on rare earth addition processes are carried out at home and abroad, and the mass production is realized under respective historical conditions, which mainly comprise the following steps: the method comprises eight methods, namely a large-ladle throwing method, a large-ladle pressing-in method, a method for blowing rare earth powder into a ladle, a method for feeding wires by using a casting injection center injection pipe, a method for hanging rare earth metal rods in a mould, a method for feeding wires by using a steel ladle, a method for feeding wires by using a tundish, a method for feeding wires by using a crystallizer and the like. The currently used methods mainly focus on: the method comprises a ladle wire feeding method and a crystallizer wire feeding method. Even under the condition of gas protection, the rare earth wire and the casting powder are contacted, when the low-temperature rare earth wire passes through a high-temperature casting powder layer, the casting powder in the contact area is possibly adhered to the surface of the metal wire and enters a molten pool along with the wire, and the defects of slag inclusion and the like are generated. Even when the sleeve is additionally arranged around the rare earth wire, the rare earth wire is continuously fed into the inner area of the sleeve, so that the temperature in the sleeve is too low, the casting powder is easy to solidify, and the rare earth wire is not beneficial to adding and casting protection; on the other hand, the wire feeding method of the crystallizer is easy to cause the performance deterioration of the continuous casting crystallizer casting powder, and the surface defect of the casting blank is caused.
Therefore, a low-cost, simple and effective rare earth adding device is needed in the continuous casting production of steel.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects of the addition of the rare earth in the prior art, the device for adding the rare earth into the molten steel is provided, and the device is convenient to use, good in rare earth adding effect, convenient to operate, simple, easy and effective.
The technical scheme of the utility model is that:
the utility model provides a device to add tombarthite in molten steel, includes the support frame, sets up the lift rotating system in the upper end of support frame, and this lift rotating system is connected with the jetting pipe, and the one end of jetting pipe is the jetting pipe head, and the gas holder is connected to the other end of this jetting pipe, sets up gas flow pressure control system in the export of gas holder, is provided with the tombarthite feed bin on the jetting pipe between gas flow pressure control system and jetting pipe head, sets up feed arrangement between tombarthite feed bin and jetting pipe.
Furthermore, the outer layer of the injection pipe is made of a refractory material, and the inner layer of the injection pipe is made of steel. The specific material can be steel with less carbon element and alloy element types and lower alloy element content than the molten steel. In the rare earth conveying process, rare earth can corrode the inner layer material of the injection pipe, and steel is selected as the inner layer material, so that the pollution to molten steel can be reduced, and more rare earth block-shaped materials can be impacted.
Furthermore, the diameter of the inner layer of the blowing pipe is 10-30 mm.
Further, the shape of the head 4 of the blowing pipe can be a trumpet shape or a straight cylinder shape, and other suitable shapes can also be provided.
The device is adopted to add rare earth for operation, and the specific steps are as follows:
1) the lifting rotary system controls a blowing pipe to be arranged above the steel ladle, the gas flow pressure control system conveys small-flow argon, and the blowing pipe blows off metallurgical slag on the surface of molten steel;
2) continuously injecting argon into the molten steel by using an injection pipe, and meanwhile, conveying the injection pipe into the molten steel to a depth of 2/3-1/3;
3) the feeding device sends the rare earth into the blowing pipe once or for a plurality of times, the flow of argon is increased, the argon drives the rare earth metal to enter molten steel, and meanwhile, the argon also plays a role in stirring the molten steel and homogenizing the rare earth components;
4) after the rare earth is added into the first molten steel deeply, the lifting rotary system controls the ascending of the injection pipe; rare earth is added through one or more different molten steel depths, so that the argon flow is reduced;
5) the lifting rotary system controls the blowing pipe to be far away from the slag air interface, and the steel added with the rare earth enters the next procedure.
The relative position of the blowing pipe in the ladle and the relative depth of the blowing pipe in the molten steel are respectively controlled by the lifting rotary system.
The utility model has the advantages that,
the device adds the tombarthite with the mode of bulk material to through argon gas cleanness, high-efficient send into the molten steel with the tombarthite, add the degree of depth and constantly diminish, reduce the contact with resistant material. The stirring effect caused by the carrier gas promotes the melting and the uniform distribution of the rare earth in the molten steel. The flow of argon is controlled by a gas flow pressure system, and the flow of argon can be increased on the premise of not causing liquid level rolling and air suction.
The device of the utility model successfully reduces the oxidation phenomenon of the rare earth under the smelting environment, solves the difficult problems of reaction of the rare earth with the refining slag and the covering slag, and has simple principle and structure, convenient maintenance, small investment and easy realization.
In addition, the addition mode of the rare earth is further optimized and improved by matching with the addition amount of the rare earth, the molten steel condition of the rare earth addition and the shape of the rare earth, all aspects are matched with each other, and the performance of the steel is greatly improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view showing the structure of an apparatus for adding rare earth to molten steel according to the present invention.
Wherein: the method comprises the following steps of 1-steel ladle, 2-molten steel, 3-steel slag, 4-blowing pipe head, 5-blowing pipe, 6-rare earth, 7-rare earth bin, 8-feeding device, 9-gas storage tank, 10-gas flow pressure control system, 11-moving rotary system and 12-support rod.
Detailed Description
In order to make the technical solutions in the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention. The addition amount of rare earth, the molten steel condition to which the rare earth is added, the shape of the rare earth, and the manner of addition of the rare earth are more clearly defined in the examples, but not limited thereto.
Example 1
A device for adding rare earth into molten steel comprises a support frame 12, wherein a lifting rotary system 11 is arranged at the upper end of the support frame 12, the lifting rotary system 11 is connected with an injection tube 5, the outer layer of the injection tube is made of refractory materials, and the inner layer of the injection tube is made of steel. The inner layer diameter of the blowing pipe is 10-30mm, and the minimum diameter is not less than 10 mm. The blowing tube head 4 may be trumpet or straight barrel shaped.
One end of the injection pipe 5 is an injection pipe head 4, the other end of the injection pipe 5 is connected with a gas storage tank 9, a gas flow pressure control system 10 is arranged at the outlet of the gas storage tank 9, a rare earth bin 7 is arranged on the injection pipe 5 between the gas flow pressure control system 10 and the injection pipe head 4, and a feeding device 8 is arranged between the rare earth bin 7 and the injection pipe 5.
Example 2
Regarding the rare earth adding mode, referring to fig. 1, it can be seen that the specific operation steps of the device for adding rare earth into molten steel are as follows:
(1) the support member 12 and the lifting rotary system 11 control the injection pipe 5 to be positioned above the ladle 1, argon gas is sealed in the gas storage tank 9, the argon gas flow and pressure control system 10 outputs small-flow argon gas with the pressure of 0.3MPa, and the injection pipe 5 blows off metallurgical slag 3 on the surface of the molten steel 2;
(2) the injection pipe 5 continuously injects argon into the molten steel 2, and simultaneously the lifting rotary system 11 sends the head 4 of the injection pipe into the depth 2/3 of the molten steel 2;
(3) the rare earth 6 is positioned in a rare earth bin 7 above the injection tube 5, the feeding device 8 sends the rare earth 6 into the injection tube 5, the argon flow is controlled to increase the argon pressure, the pressure is 1.5MPa, and the argon drives the rare earth 6 to enter the molten steel 2;
(4) after rare earth is added into certain depth of molten steel, the lifting rotary system 11 controls the blowing pipe 5 to ascend, and the rare earth continues to be added at other depths; when the depth of the molten steel 2 in the head 4 of the injection tube is 1/3, the feeding device 8 sends the rare earth 6 into the injection tube 5, the argon flow is controlled to increase the argon pressure, the pressure is 0.8MPa, and the argon drives the rare earth metal 6 to enter the molten steel 2;
(5) and the lifting rotary system 11 controls the blowing pipe 5 to be far away from a slag air interface to complete rare earth addition, and molten steel enters a soft argon blowing process.
Example 3
The method for adding rare earth into steel by matching with the device is controlled in four aspects of the addition amount of rare earth, the molten steel condition for adding rare earth, the shape of rare earth and the addition mode of rare earth.
The utility model discloses a method for adding tombarthite in steel, the concrete scheme is:
(1) the addition amount of the rare earth is controlled to be (10-200) × 10-6The rare earth is pure La, pure Ce and metal material using La and Ce as main elements, the excessive addition of rare earth can not only improve the performance of steel, but also influence the normal production of steel, even cause the scrapping of material, the rare earth is not suitable for pre-deoxidation and desulfurization agent, the rare earth element only is used as deep deoxidation and deep desulfurization agent, the addition amount is (10-200) × 10-6。
(2) Molten steel adding conditions of rare earth are as follows: t [ O ]]≤10×10-6，[S]≤30×10-6. When the deoxidation and desulfurization effects are good, the rare earth is added, so that the deep deoxidation and desulfurization effects are achieved, and the forms of oxygen and sulfur inclusions can be well controlled.
(3) Shape of rare earth: the method adopts blocky rare earth, the equivalent diameter of the blocky rare earth is 5-40mm, and the length-width ratio or the axial width ratio is 1-3.
Rare earth is close to the high-temperature environment of molten steel, oxidation can be accelerated, and the finer the particle size of the material, the larger the specific surface area, and the greater the probability and degree of oxidation. Therefore, the rare earth bulk material with larger specific surface area is more beneficial to adding molten steel. Since the density of the rare earth La and Ce is slightly less than that of steel, the larger the size of the block rare earth is at the same molten steel temperature, the longer the time required for melting is, and the higher the possibility of floating to a steel slag interface is.
(4) The rare earth addition mode is as follows: rare earth is sprayed into molten steel by a spray pipe by using inert gas as a carrier, the inert gas is argon, the service pressure of the argon is 0.2MPa-1.5MPa, the adding depth is continuously reduced, and the contact with a refractory material is reduced. The stirring effect caused by the carrier gas promotes the melting and the uniform distribution of the rare earth in the molten steel. The flow of argon is controlled by a gas flow pressure system, and the flow of argon can be increased on the premise of not causing liquid level rolling and air suction.
When the rare earth is added, the retention time of the rare earth above a slag-air interface is reduced as much as possible, the contact between the rare earth and metallurgical slag is reduced, the time required for the rare earth to be uniformly diffused in molten steel is reduced, and the rare earth can be added cleanly, safely and efficiently by the aid of inert gas.
In the depth direction of molten steel, because the outer layer of the injection pipe is made of refractory materials, in order to reduce the reaction of refractory materials of the injection pipe and rare earth added into the molten steel and improve the service life of the injection pipe, particularly the head part of the injection pipe, the head part of the injection pipe is controlled above the position for injecting the rare earth as far as possible, which means that the rare earth is added at a deeper position of a steel ladle firstly and the position of the injection pipe is continuously and upwards lifted.
The specific steps of the rare earth adding mode in the step (4) are as follows:
1) the injection pipe firstly conveys a small flow of argon above the steel ladle and blows off metallurgical slag on the surface of molten steel;
2) continuously injecting argon into the molten steel by using an injection pipe, and meanwhile, conveying the injection pipe into the molten steel to a depth of 2/3-1/3;
3) increasing the flow of argon, feeding the rare earth into a blowing pipe once or for a plurality of times, driving the rare earth into molten steel by the argon, and stirring the molten steel and homogenizing the rare earth components by the argon;
4) after the rare earth is added deeply into the first molten steel, the blowing pipe is lifted; rare earth is added through one or more different molten steel depths, so that the argon flow is reduced;
5) and (4) keeping the blowing pipe away from the slag air interface, and adding the rare earth steel to enter the next procedure.
Example 1
Operation of adding rare earth to molten steel
The production process comprises the following steps: blast furnace molten iron + high-quality scrap steel → 50t EAF ultrahigh power eccentric bottom tapping DC electric arc furnace → 50t LF refining furnace → 50t VD vacuum degassing furnace → 3 machine 3 stream large square billet continuous casting CC of 260mm × 300mm → slow cooling → heating → continuous rolling (→ shot blasting → straightening → flaw detection → warehousing)
The production steel grade is bearing steel GCr15, and the chemical composition (%) is C: 0.96-0.98, Si: 0.18-0.25, Mn: 0.28-0.33, and 1.42-1.52 of Cr.
After VD procedure is finished, before continuous casting procedure, T [ O ] in molten steel is measured]≤4.6×10-6，[S]≤18×10-6The condition of molten steel added with rare earth is achieved, the adding amount of the rare earth is 150 × 10-6The equivalent diameter of the rare earth is 25-30mm, the adding amount of the rare earth is 7.5Kg, and the rare earth is added in two times on average.
The specific steps of the rare earth adding mode are as follows:
1) the injection pipe firstly conveys a small flow of argon above the steel ladle, the pressure is 0.3MPa, and the metallurgical slag on the surface of the molten steel is blown open;
2) the injection pipe continuously injects argon gas into the molten steel, and simultaneously sends the injection pipe to the molten steel depth 2/3;
3) increasing the flow of argon gas, the pressure is 1.5MPa, and feeding the rare earth into a blowing pipe once or for a plurality of times to homogenize the action of the rare earth components;
4) after rare earth is added into the first molten steel deeply, the blowing pipe is lifted to the molten steel depth of 1/3, the rare earth is sent into the blowing pipe once or for a plurality of times, the pressure is 0.8MPa, the argon drives the rare earth to enter the molten steel, and meanwhile, the argon also plays a role in stirring the molten steel; reducing the flow of argon;
5) and (4) keeping the blowing pipe away from the slag air interface, and adding the rare earth steel to enter the next procedure.
Although the present invention has been described in detail by referring to the drawings in conjunction with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and substance of the present invention, and these modifications or substitutions are intended to be within the scope of the present invention/any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (4)
1. The utility model provides a device to add tombarthite in molten steel, a serial communication port, including the support frame, set up the lift rotating system in the upper end of support frame, this lift rotating system is connected with the jetting pipe, and the one end of jetting pipe is the jetting pipe head, and the gas holder is connected to the other end of this jetting pipe, sets up gas flow pressure control system in the export of gas holder, is provided with the tombarthite feed bin on the jetting pipe between gas flow pressure control system and jetting pipe head, sets up feed arrangement between tombarthite feed bin and jetting pipe.
2. The apparatus for adding rare earth to molten steel of claim 1, wherein the material of the outer layer of the blowing tube is refractory and the material of the inner layer is steel.
3. The apparatus for adding rare earth into molten steel according to claim 2, wherein the inner layer of the blowing tube has a diameter of 10 to 30 mm.
4. The apparatus for adding rare earth to molten steel according to claim 1, wherein the blowing tube head (4) has a horn shape or a straight tube shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921762845.9U CN211689145U (en) | 2019-10-18 | 2019-10-18 | Device for adding rare earth into molten steel |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921762845.9U CN211689145U (en) | 2019-10-18 | 2019-10-18 | Device for adding rare earth into molten steel |
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| CN211689145U true CN211689145U (en) | 2020-10-16 |
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| CN201921762845.9U Active CN211689145U (en) | 2019-10-18 | 2019-10-18 | Device for adding rare earth into molten steel |
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