WO2021203851A1 - 一种利用长水口喷粉进行钢水镁钙处理的方法 - Google Patents

一种利用长水口喷粉进行钢水镁钙处理的方法 Download PDF

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Publication number
WO2021203851A1
WO2021203851A1 PCT/CN2021/077322 CN2021077322W WO2021203851A1 WO 2021203851 A1 WO2021203851 A1 WO 2021203851A1 CN 2021077322 W CN2021077322 W CN 2021077322W WO 2021203851 A1 WO2021203851 A1 WO 2021203851A1
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Prior art keywords
powder
shroud
magnesium
calcium
molten steel
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PCT/CN2021/077322
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English (en)
French (fr)
Inventor
胡绍岩
王德永
屈天鹏
王慧华
田俊
侯栋
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苏州大学
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Publication of WO2021203851A1 publication Critical patent/WO2021203851A1/zh

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Classifications

    • 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
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/072—Treatment with gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • B22D41/58—Pouring-nozzles with gas injecting means

Definitions

  • the invention belongs to the technical field of clean steel smelting, and specifically relates to a method for treating molten steel with magnesium and calcium by spraying powder with a long nozzle.
  • Non-metallic inclusions in steel are the most direct cause of various defects in steel materials. Due to the complex sources of inclusions, it is difficult to completely remove them during the steelmaking process. Therefore, modification treatment and harmless control of inclusions have become An important method of clean steel production.
  • the commonly used inclusion modification treatment methods include magnesium treatment and calcium treatment. By adding metallic magnesium or metallic calcium to molten steel, the composition, size and morphology of the inclusions are transformed to reduce the harm of inclusions to steel; moreover, Studies have shown that only a small amount (less than 30ppm) of [Mg] and [Ca] in molten steel can be used to modify inclusions. The beneficial effects of magnesium treatment and calcium treatment on improving the quality of steel products have been extensively proven.
  • magnesium and calcium has troubled steel workers for a long time.
  • Magnesium metal and calcium metal are extremely active, with low boiling point and high vapor pressure. Direct addition of molten steel can easily cause explosion and splash accidents.
  • the commonly used method in industrial production is the wire feeding method, which mixes magnesium/calcium with aluminum, silicon, iron and other alloys to prepare a passivation alloy, and the low-carbon iron sheet is wrapped around it to make a magnesium alloy wire or a calcium alloy wire.
  • the wire feeding machine is used The magnesium alloy wire or calcium alloy wire is quickly fed through the slag layer into the lower part of the ladle.
  • magnesium and calcium are very volatile, a large amount of magnesium vapor or calcium vapor overflows into the ladle without being dissolved.
  • the yield of magnesium/calcium by the wire feeding method in industrial production is not only low but also unstable, and the yield is only 5% ⁇ 15%;
  • alloying elements such as aluminum and silicon fed together with magnesium/calcium will also cause fluctuations in the composition of molten steel.
  • the prior art discloses a method for magnesium treatment in a tundish.
  • a breathable brick and an electric heating gasification chamber are installed at the bottom of the tundish.
  • Magnesium powder is sprayed into the electric heating gasification chamber by inert gas.
  • the indoor gasification becomes magnesium vapor, and the magnesium vapor enters the molten steel through the air-permeable brick to achieve the effect of magnesium treatment; however, the magnesium powder may not be 100% vaporized after entering the electric heating gasification chamber. It is easy to cause the bottom-blowing and ventilating bricks to block and fail. Once the bottom-blowing and ventilating bricks fail, the replacement cost is high and the time is long.
  • the present invention provides a new method for spraying magnesium powder or calcium powder into the steel stream using the shroud.
  • the steel stream enters the tundish and is evenly dissolved in the molten steel to complete the modification treatment of the inclusions.
  • the principle of the present invention is: (1) Unlike the bottom blowing of the ladle or the bottom blowing of the tundish, the inner wall of the shroud does not bear the static pressure of the molten steel, and even if the width of the powder spraying slit is large, no molten steel inverted accident will occur; (2) The amount of metal magnesium powder or metal calcium powder required for magnesium treatment or calcium treatment is very small, the amount of steel per ton is less than 0.05kg, combined with the casting speed of the ladle, the powder injection flow rate is less than 0.5kg/min, and it is feasible to spray in the shroud (3) The long nozzle is a consumable, which is easy to replace and low in cost; (4) The buoyancy effect of argon, magnesium vapor, and calcium vapor can help slow down the flow rate of the steel stream and reduce the injection area of the tundish by the steel stream. The impact.
  • the technical scheme of the present invention is: a method for treating molten steel with powder spraying for magnesium and calcium treatment includes the following steps: a slit nozzle is arranged on the inner side wall below the bowl of the nozzle; during the molten steel casting process, the magnesium powder flows or The flow of calcium powder is sprayed into the cavity of the shroud from a slit nozzle to complete the magnesium-calcium treatment of molten steel.
  • the shroud for powder spraying for molten steel magnesium-calcium treatment includes a shroud and a slit nozzle; the two ends of the shroud are the shroud bowl mouth and shroud outlet; Slot nozzle.
  • a device for powder spraying based on a shroud for the treatment of magnesium and calcium for molten steel includes a shroud and a slit nozzle; the two ends of the shroud are the shroud bowl and shroud outlet respectively; on the side wall of the shroud, under the bowl A slit nozzle is provided; the slit nozzle is connected with the powder spraying system through a powder conveying pipeline.
  • the upper surface of the bowl mouth of the shroud is provided with a sealing material; the bowl mouth of the shroud is provided with vent holes, which are used for blowing argon gas to avoid air entrainment between the ladle nozzle and the bowl mouth of the shroud ;
  • the slit nozzle is connected with the powder spraying system, and the width of the slit nozzle is 0.1 ⁇ 2mm.
  • the magnesium powder flow or the calcium powder flow uses argon gas as the carrier gas; the powder spraying flow rate of the magnesium powder or calcium powder is 0.01 ⁇ 0.5kg/min; the solid-gas ratio of the magnesium powder flow or the calcium powder flow is 10-50 ; Too much solid-gas ratio can easily block the powder conveying pipeline, and too small solid-gas ratio can easily cause the molten steel in the tundish injection zone to churn violently, and the molten steel is prone to secondary oxidation.
  • the upper surface of the shroud bowl is provided with a sealing material for sealing the shroud and the ladle drain.
  • the specific sealing material is an existing product, which can be bonded to the upper surface of the shroud bowl.
  • the specific position is not limited, as long as it can Just play a sealing role.
  • the bowl mouth of the shroud is provided with a vent hole for introducing gas after the shroud is sealed with the ladle lower nozzle to prevent air from being drawn into the shroud, and it can also inhibit the overflow of magnesium vapor or calcium vapor during the powder spraying process; It is a conventional method to connect the existing argon gas nozzle to the vent hole to transport argon; the size and number of the vent hole are not limited, and those skilled in the art design according to actual production.
  • the disclosed method for treating molten steel with magnesium and calcium by spraying powder with a long nozzle specifically includes the following steps.
  • a sealing material is provided between the bowl mouth of the shroud and the ladle drain.
  • the argon gas is sprayed into the bowl mouth and under the ladle through the vent hole on the upper edge of the bowl mouth.
  • the argon gas is sprayed into the bowl mouth and under the ladle through the vent hole on the upper edge of the bowl mouth.
  • the particle size of the magnesium powder or calcium powder is 100-400 mesh.
  • argon gas is sprayed between the bowl mouth of the shroud and the lower nozzle of the ladle for sealing to prevent the steel flow from entraining air and magnesium vapor and calcium vapor from overflowing.
  • the inner wall surface below the bowl mouth of the shroud is provided for spraying.
  • the slit nozzle for powder is connected to the powder spraying system through the powder conveying pipeline; in the molten steel casting process, the powder spraying system uses argon as the carrier gas to inject fine magnesium powder or calcium powder, magnesium powder or calcium powder After flowing through the powder conveying pipeline, the slit nozzle is sprayed into the inner cavity of the shroud.
  • the magnesium powder or calcium powder and the molten steel circulating in the shroud are mixed vigorously and further in the tundish injection area.
  • the dissolution is uniform, and the residence time of the molten steel in the tundish is used to complete the modification treatment of the inclusions in the molten steel by magnesium or calcium.
  • the present invention opens the argon gas required for the sealing of the shroud, opens the powder spraying carrier gas, does not spray powder temporarily, and drains the air inside the shroud; opens the ladle nozzle slide plate, and the molten steel in the ladle passes through the nozzle The nozzle flows into the tundish, and when the liquid level in the injection zone of the tundish submerges the outlet of the shroud, start to spray magnesium powder or calcium powder continuously according to the calculated flow; before the end of casting, first stop the powder spraying and keep the powder spraying carrier gas to continue Spray until there is no steel flow in the shroud at the end of casting, turn off the powder carrier gas, and turn off the argon required for sealing.
  • the slit nozzle has a width of 0.1-2 mm; when spraying magnesium powder or calcium powder, a dense phase conveying method is adopted, and the solid-gas ratio is 10-50.
  • the beneficial effects of the present invention are: (1) In the condition that the bowl mouth of the shroud is well sealed, the magnesium powder or calcium powder is sprayed into the shroud, and the magnesium powder or calcium powder and the steel flow circulating in the shroud are fully Contact and mix uniformly, the molten steel flowing downward can effectively inhibit the floating and overflow of magnesium vapor or calcium vapor, greatly improving the yield of metallic magnesium or calcium, and the yield of magnesium or calcium can reach more than 50%; (2) Utilization The residence time of molten steel in the tundish, [Mg] or [Ca] dissolved in molten steel can achieve excellent inclusion modification effects; (3) The equipment of the present invention is simple, and only a small modification to the structure of the shroud is required.
  • the size of the slit nozzle is larger than the bottom blowing element, and it is not easy to be blocked; (4) The replacement of the shroud is convenient and low in cost; (5) The magnesium powder or calcium powder of the present invention does not touch the air during the blowing process, and directly enters the inside of the molten steel , The safety factor is high.
  • Figure 1 is a schematic diagram of related devices mentioned in the present invention; Figure: 1. Ladle; 2. Ladle nozzle slide plate; 3. Ladle lower nozzle; 4. Long nozzle; 4-1, Long nozzle bowl; 4-2 , Vent holes; 4-3, slit nozzles; 4-4, the outlet of the shroud; 5, the tundish; 6, the powder conveying pipeline; 7, the powder spraying system.
  • the powder conveying pipeline, the powder injection system, the shroud and the ladle nozzle are existing components, and the specific shape and number of the slit nozzles are not limited; the inventiveness of the present invention lies in the inner wall surface below the bowl mouth of the shroud
  • the sealing material is designed to combine with the vent hole to input argon gas to prevent the steel stream from entraining air and magnesium vapor and calcium vapor from overflowing.
  • the present invention does not require other structural changes or the use of treatment agents, overcomes the technical prejudice that the prior art adopts wire feeding method for magnesium-calcium modification, and creatively proposes the structure and method of adding magnesium-calcium powder in the molten steel flow process. Obviously improve the yield of calcium and magnesium, especially the adopted structure is very simple and safe, the method is very easy and does not change the existing process, which is a significant improvement.
  • the shroud for powder spraying for molten steel magnesium-calcium treatment includes shroud 4 and slit nozzle 4-3; both ends of the shroud are shroud bowl mouth 4-1 and shroud outlet 4-4; the shroud On the side wall, a slit nozzle is arranged under the mouth of the bowl; the slit nozzle is a nozzle structure commonly used in the field.
  • a device for spraying powder for molten steel magnesium-calcium treatment based on a shroud is used in the following embodiments, which includes a shroud 4 and a slit nozzle 4-3; both ends of the shroud are the shroud 4 -1.
  • sealing materials 4-5 used to seal the shroud and the ladle drain.
  • the specific sealing material is an existing product, which can be glued to the upper surface of the shroud bowl.
  • the specific position is not limited, as long as it can play a sealing role.
  • the orientation of the present invention is the positional relationship during actual production; the shroud bowl is provided with vent holes 4-2, which are used to pass air after the shroud and the ladle drain are sealed to prevent air from being drawn into the shroud and spraying Magnesium vapor can also be prevented from overflowing during the powder process; the existing argon nozzle can be connected to the vent hole, which is a conventional method for argon delivery; the size and number of the vent hole are not limited, and those skilled in the art can design according to actual production.
  • the bowl mouth 4-1 of the shroud is connected to the ladle nozzle 3
  • the ladle nozzle slide plate 2 is opened, and the molten steel flows into the tundish, which is a conventional process.
  • Example 1 The present invention is applied in the casting process of a 250t ladle.
  • the upper edge of the nozzle of the shroud is provided with vent holes, and the inner wall of the bottom of the bowl is provided with two symmetrical slit nozzles, each of which has a width of 1.5 mm, the length is 20mm, the length direction of the slit nozzle is parallel to the axial direction of the shroud, and the two slits are respectively connected to the powder spraying system through two powder conveying pipes;
  • the flow parameter involved in the present invention is each slit type The flow parameter of the nozzle.
  • the total flow rate of magnesium powder in this embodiment is 0.1 kg/min, so the flow rate of magnesium powder in each slit is 0.05 kg/min.
  • the molten steel is treated with magnesium.
  • the target [Mg] content of the molten steel is 0.001% ⁇ 0.002%; the total casting time of a 250t ladle is 50min, and the molten steel flow rate during the casting process is 5t/min.
  • the processing steps are as follows.
  • the implementation results show that the average [Mg] content in the cast steel slab is 0.0011%, the recovery rate of magnesium powder can reach 55%, the number of inclusions in the steel slab is significantly reduced, and the cluster-like Al 2 O 3 is all modified to Small-sized MgO or MgO ⁇ Al 2 O 3 inclusions can significantly improve the quality of steel.
  • the yield difference of magnesium powder is at most 2%, and the inclusions are obviously reduced, and the quality of steel is obviously improved; it shows that the magnesium powder yield of the method of the present invention is high and stable.
  • Comparative Example 1 On the basis of Example 1, the solid-gas ratio was adjusted to 5, and the rest remained unchanged. The yield of magnesium powder was 31%. Slag entrapment and secondary oxidation of molten steel occurred in the tundish. The number of large-particle inclusions has increased significantly.
  • Example 2 The present invention is applied in the casting process of a 120t ladle.
  • the upper edge of the nozzle of the shroud is provided with a vent hole, and a slit nozzle is provided on the inner wall of the bottom of the bowl.
  • the width of the slit is 1mm and the length is 20mm.
  • the length of the slit is parallel to the axial direction of the shroud, and the slit is connected with the powder spraying system through a powder conveying pipe.
  • the molten steel is treated with calcium.
  • the target [Ca] content of the molten steel is 0.001% ⁇ 0.002%; the total casting time of the 120t ladle is 40min, and the molten steel flow rate during the casting process is 3t/min.
  • the specific treatment Proceed as follows.
  • the implementation results show that the average [Ca] content in the cast steel billet is 0.0012%, the recovery rate of calcium powder can reach 60%, and the cluster-like Al 2 O 3 inclusions in the steel billet are significantly reduced; moreover, due to the recovery of calcium
  • the yield is stable, accurate calcium treatment is easier to achieve, and the high melting point Al 2 O 3 inclusions are transformed into the low melting point 12CaO ⁇ 7Al 2 O 3 inclusions, and the quality of the steel is significantly improved.
  • the prior art adopts the thread feeding method, and the yield of calcium and magnesium is low and unstable.
  • the current calculation formula for the yield of calcium and magnesium is as follows (taking calcium as an example): .
  • the yield of pure calcium wire treatment disclosed in the prior art is as follows: .
  • the invention overcomes the defects of serious spattering, low yield and instability of the wire feeding method, and pioneers the method of continuous powder spraying for magnesium-calcium treatment during the casting process, which can not only avoid the influence of other elements in the magnesium-calcium alloy wire, but also Can greatly increase the yield of magnesium and calcium.

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
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Abstract

一种在钢水浇铸过程中，利用长水口（4）喷粉进行钢水镁钙处理的方法。在长水口（4）的内壁面上设置有狭缝式喷嘴（4-3），浇铸过程中通过狭缝式喷嘴（4-3）连续地向长水口（4）内喷吹微细镁粉或钙粉，镁粉或钙粉与长水口（4）内向下流动的钢水剧烈混合并快速溶解，利用钢水在中间包（5）内的停留时间完成镁或钙对钢水中夹杂物的改性处理。仅需对长水口（4）的结构进行调整，成本低廉，更换便捷，安全高效，可以将镁或钙的收得率提高至50％以上。

Description

一种利用长水口喷粉进行钢水镁钙处理的方法 技术领域
本发明属于洁净钢冶炼技术领域，具体涉及一种利用长水口喷粉进行钢水镁钙处理的方法。
 背景技术
钢中非金属夹杂物是导致钢铁材料出现各类缺陷的最直接诱因，由于夹杂物来源复杂，炼钢过程中难以将其完全去除，因此，对夹杂物进行改性处理和无害化控制成为洁净钢生产的重要方法。目前常用的夹杂物改性处理方法包括镁处理和钙处理，通过向钢水中加入金属镁或金属钙的方式实现夹杂物成分、尺寸和形貌的转变，降低夹杂物对钢的危害；而且，研究表明钢水中只需微量（小于30ppm）的[Mg]和[Ca]便可以实现夹杂物的改性处理。镁处理和钙处理对改善钢铁产品质量的有益效果已经得到了广泛的实践证明。
但是，长期以来镁和钙的加入方式一直困扰着炼钢工作者。金属镁和金属钙的性质极为活泼，沸点低，蒸气压高，直接加入钢水易引起***和喷溅事故。目前在工业生产中常用的方法是喂线法，将镁/钙与铝、硅、铁等合金混合制备钝化合金，***包裹低碳铁皮制成镁合金线或钙合金线，利用喂线机将镁合金线或钙合金线快速穿过渣层喂入钢包下部。但是，由于镁和钙极易挥发，大量镁蒸气或钙蒸汽尚未溶解便溢出钢包，目前工业生产中喂线法的镁/钙收得率不仅低而且不稳定，收得率仅为5%~15%；此外，随镁/钙一同喂入的铝、硅等合金元素也将造成钢水成分波动。
现有技术公开了一种在中间包进行镁处理的方法，在中间包底部安装透气砖和电加热气化室，利用惰性气体将镁粉喷吹到电加热气化室，镁粉在气化室内气化成镁蒸气，镁蒸气通过透气砖进入钢水中，起到镁处理的效果；但是，镁粉进入电加热气化室后未必能够100%气化，部分镁粉在惰性气体和镁蒸气的带动下上升进入透气砖，极易造成底吹透气砖堵塞失效，底吹透气砖一旦失效，更换的成本高、时间长。
 技术问题
为了解决炼钢过程中的镁/钙加入问题，本发明提供一种利用长水口将镁粉或钙粉喷入钢流的新方法，镁粉或钙粉在长水口内部与钢水混合，并随钢流进入中间包，均匀溶解在钢水中，完成夹杂物的改性处理。
本发明的原理是：（1）与钢包底吹或中间包底吹不同，长水口内壁面不承受钢水静压力，即使喷粉的狭缝宽度较大也不会发生钢水倒灌事故；（2）镁处理或钙处理所需的金属镁粉或金属钙粉用量很小，吨钢用量小于0.05kg，结合钢包的浇铸速度，喷粉流量小于0.5kg/min，具备在长水口内喷吹的可行性；（3）长水口为消耗品，更换简便，成本低廉；（4）利用氩气、镁蒸气、钙蒸汽的浮力作用有助于减缓钢流的流速，减轻钢流对中间包注流区的冲击。
 技术解决方案
本发明的技术方案是：利用长水口喷粉进行钢水镁钙处理的方法，包括以下步骤：在长水口碗口下方的内侧壁上设置狭缝式喷嘴；在钢水浇铸过程中，镁粉流或钙粉流由狭缝式喷嘴喷入长水口的内腔，完成钢水镁钙处理。
钢水镁钙处理喷粉用长水口，包括长水口以及狭缝式喷嘴；所述长水口两端分别为长水口碗口、长水口出口；所述长水口内侧壁面上、碗口下方设置有狭缝式喷嘴。
基于长水口的钢水镁钙处理喷粉用装置，包括长水口以及狭缝式喷嘴；所述长水口两端分别为长水口碗口、长水口出口；所述长水口侧壁上，碗口下方设置有狭缝式喷嘴；狭缝式喷嘴通过输粉管道与喷粉***相连。
本发明中，长水口的碗口上表面设有密封材料；长水口的碗口上设有透气孔，所述透气孔用于喷吹氩气，避免钢包下水口与长水口碗口之间卷吸空气；狭缝式喷嘴与喷粉***相连，狭缝式喷嘴的宽度为0.1~2mm。
本发明中，镁粉流或钙粉流以氩气为载气；镁粉或钙粉的喷粉流量为0.01~0.5kg/min；镁粉流或钙粉流的固气比为10~50；固气比太大容易堵塞输粉管道，固气比太小容易导致中间包注流区的钢水剧烈翻腾，钢水容易二次氧化。
本发明中，在钢水浇铸过程中，当长水口的碗口与钢包下水口对接后，通过透气孔喷吹氩气，然后输入喷粉载气，最后喷入镁粉流或钙粉流。
优选的，长水口碗口上表面设有密封材料，用于将长水口与钢包下水口密封，具体密封材料为现有产品，其可粘接在长水口碗口上表面，具***置没有限定，只要可以起到密封作用即可。
优选的，长水口碗口上设有透气孔，用于在长水口与钢包下水口密封后通入气体，避免空气卷入长水口，在喷粉过程中也可以抑制镁蒸气或钙蒸汽外溢；可以将现有氩气喷嘴接入透气孔，为常规方法，进行氩气的输送；透气孔的大小以及数量没有限定，本领域技术人员根据实际生产设计。
本发明公开的利用长水口喷粉进行钢水镁钙处理的方法具体包括以下步骤。
（1）将镁粉或者钙粉加入喷粉***内。
（2）将长水口的碗口与钢包下水口对接，碗口上的透气孔喷吹氩气，打开喷粉载气，暂不喷吹镁粉或钙粉，然后打开钢包水口滑板，开始浇铸。
（3）待中间包注流区的液面淹没长水口出口时，开始喷吹镁粉或钙粉。
（4）在钢包浇铸结束前，停止喷吹镁粉或者钙粉，并保持打开喷粉载气；然后停止浇铸，当长水口内没有钢流时，关闭喷粉载气；完成钢水镁钙处理。
本发明中，浇铸结束前为本领域常识。
优选的，长水口的碗口与钢包下水口之间设有密封材料。
优选的，将长水口的碗口与钢包下水口对接后，输入氩气，在密封材料密封下，打开密封所需的氩气，氩气通过碗口上沿的透气孔喷入碗口与钢包下水口之间，避免空气卷入长水口，在喷粉过程中也可以抑制镁蒸气或钙蒸气外溢。
优选的，镁粉或者钙粉的粒度为100~400目。
本发明在长水口的碗口与钢包的下水口之间喷吹氩气进行密封，防止钢流卷吸空气和镁蒸汽、钙蒸汽溢出，在长水口碗口下方的内壁面上设置有用于喷粉的狭缝式喷嘴，狭缝式喷嘴通过输粉管道与喷粉***相连；在钢水浇铸过程中，喷粉***以氩气为载气喷吹微细镁粉或钙粉，镁粉或钙粉流经输粉管道后由狭缝式喷嘴喷入长水口的内腔，受钢流的卷吸作用，镁粉或钙粉与长水口内流通的钢水剧烈混合，并在中间包注流区进一步溶解均匀，利用钢水在中间包内的停留时间完成镁或钙对钢水中夹杂物的改性处理。
本发明在开启钢包水口滑板之前，打开长水口密封所需的氩气，打开喷粉载气，暂不喷粉，将长水口内部的空气排净；打开钢包水口滑板，钢包内的钢水经由长水口流入中间包，待中间包注流区的液面淹没长水口出口时，开始按照计算的流量连续喷吹镁粉或钙粉；在浇铸结束之前，首先停止喷粉，保持喷粉载气继续喷吹，直至浇铸结束长水口内没有钢流，关闭喷粉载气，关闭密封所需氩气。
优选的，所述狭缝式喷嘴宽度为0.1~2mm；喷镁粉或者钙粉时，采用浓相输送方式，固气比为10~50。
 有益效果
本发明的有益效果是：（1）在长水口的碗口部位良好密封的情况下，将金属镁粉或钙粉喷入长水口内，镁粉或钙粉与长水口内流通的钢流充分接触并混合均匀，向下流动的钢水可以有效抑制镁蒸气或钙蒸汽的上浮溢出，大幅提高金属镁或钙的收得率，镁或钙的收得率可达50%以上；（2）利用钢水在中间包内的停留时间，溶解于钢水的[Mg]或[Ca]可实现优异的夹杂物改性效果；（3）本发明的设备简单，只需对长水口的结构进行小幅改动，狭缝式喷嘴的尺寸大于底吹元件，不易堵塞；（4）长水口的更换便捷，成本低廉；（5）本发明的镁粉或钙粉在喷吹过程中不接触空气，直接进入钢水内部，安全系数高。
 附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍。
图1为本发明所提及的相关装置示意图；图中：1，钢包；2，钢包水口滑板；3，钢包下水口；4，长水口；4-1，长水口的碗口；4-2，透气孔；4-3，狭缝式喷嘴；4-4，长水口的出口；5，中间包；6，输粉管道；7，喷粉***。
 本发明的实施方式
本发明中，输粉管道、喷粉***、长水口与钢包下水口等为现有部件，狭缝式喷嘴的具体形状以及数量没有限定；本发明的创造性在于在长水口的碗口下方内侧壁面上设置有用于喷粉的狭缝式喷嘴，并且设计密封材料结合透气孔输入氩气，防止钢流卷吸空气和镁蒸汽、钙蒸汽溢出。本发明不需要其他结构变化或处理剂的使用，克服了现有技术都是采用喂线法进行镁钙改性的技术偏见，创造性的提出在钢液流动过程加入镁钙粉的结构与方法，明显提高钙镁收得率，尤其是采用的结构十分简单、安全，方法非常容易且不改变现有工艺，为显著的进步。
下面结合具体实施例对本发明的技术方案作进一步说明。
应当理解的是，以下描述的具体实施例仅用于解释本发明，并不用于限定本发明。凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围内。
钢水镁钙处理喷粉用长水口，包括长水口4以及狭缝式喷嘴4-3；所述长水口两端分别为长水口碗口4-1、长水口出口4-4；所述长水口侧壁上，碗口下方设置有狭缝式喷嘴；狭缝式喷嘴为本领域常用的喷嘴结构。
参见附图1，基于长水口的钢水镁钙处理喷粉用装置用于以下实施例，其包括长水口4以及狭缝式喷嘴4-3；所述长水口两端分别为长水口碗口4-1、长水口出口4-4；所述长水口侧壁上，碗口下方设置有狭缝式喷嘴；狭缝式喷嘴通过输粉管道6与喷粉***7相连；长水口碗口上表面设有密封材料4-5，用于将长水口与钢包下水口密封，具体密封材料为现有产品，其可粘接在长水口碗口上表面，具***置没有限定，只要可以起到密封作用即可，本发明所述方位为实际生产时的位置关系；长水口碗口上设有透气孔4-2，用于在长水口与钢包下水口密封后通入气体，避免空气卷入长水口，在喷粉过程中也可以抑制镁蒸气外溢；可以将现有氩气喷嘴接入透气孔，为常规方法，进行氩气的输送；透气孔的大小以及数量没有限定，本领域技术人员根据实际生产设计。生产过程中，钢包1旋转至浇铸位置后，将长水口的碗口4-1与钢包下水口3对接，打开钢包水口滑板2，将钢液流入中间包，为常规工艺。
实施例 1 ：本发明应用在250t钢包的浇铸过程中，长水口的碗口上沿设置有透气孔，碗口底部内壁上设置有两条对称的狭缝式喷嘴，每条狭缝的宽度为1.5mm，长度为20mm，狭缝式喷嘴的长度方向平行于长水口的轴向，两条狭缝分别通过两条输粉管道与喷粉***相连；本发明涉及的流量参数为每条狭缝式喷嘴的流量参数。此实施例总的镁粉流量为0.1kg/min，因此每条狭缝的镁粉流量为0.05kg/min。
在生产低碳微合金钢时，对钢水进行镁处理，钢水的目标[Mg]含量为0.001%~0.002%；250t钢包的总浇铸时间为50min，浇铸过程中的钢水流量为5t/min，具体的处理步骤如下。
（1）钢包旋转至浇铸位置后，将长水口的碗口与钢包下水口对接，两者之间通过密封材料密封，将现有氩气喷嘴***透气孔，打开密封所需的氩气，氩气通过碗口上沿的透气孔喷入碗口与钢包下水口之间，避免空气卷入长水口，在喷粉过程中也可以抑制镁蒸气外溢。
（2）打开喷粉载气（氩气），每条狭缝式喷嘴的载气流量为2.5L/min，10s后打开钢包水口滑板，开始浇铸。
（3）钢包内的钢水经由长水口流入中间包，待中间包注流区的液面淹没长水口出口时，在喷粉载气流量不变的情况下开始喷吹镁粉，每条狭缝式喷嘴的喷粉流量为0.05kg/min，固气比为11.2，所选镁粉的粒度为200目。
（4）在钢包浇铸结束前，首先停止喷粉，保持喷粉载气继续喷吹，然后关闭钢包水口滑板，停止浇铸，待长水口内没有钢流时，关闭喷粉载气，关闭密封所需氩气（浇铸过程一直存在），拆下长水口，准备下一包钢水的浇铸。
实施结果表明，浇铸所得钢坯中的平均[Mg]含量为0.0011%，镁粉的收得率可达55%，钢坯中的夹杂物数量明显减少，团簇状Al 2O 3全部被改性为小尺寸的MgO或MgO·Al 2O 3夹杂物，钢材质量得到明显改善。
同样的方法浇铸十包钢水，镁粉的收得率相差最大为2%，且夹杂物明显减少，钢材质量得到明显改善；说明本发明方法的镁粉收得率高且稳定。
对比例 1 ：在实施例1的基础上，将固气比调整为5，其余不变，镁粉的收得率为31%，钢水在中间包内发生卷渣和二次氧化，钢坯中的大颗粒夹杂物数量明显增多。
实施例 2 ：本发明应用在120t钢包的浇铸过程中，长水口的碗口上沿设置有透气孔，碗口底部内壁上设置有一条狭缝式喷嘴，狭缝宽度为1mm，长度为20mm，狭缝的长度方向平行于长水口的轴向，狭缝通过输粉管道与喷粉***相连。
在生产铝镇静钢时，对钢水进行钙处理，钢水的目标[Ca]含量为0.001%~0.002%；120t钢包的总浇铸时间为40min，浇铸过程中的钢水流量为3t/min，具体的处理步骤如下。
（1）钢包旋转至浇铸位置后，将长水口的碗口与钢包下水口对接，两者之间通过密封材料密封，将现有氩气喷嘴***透气孔，打开密封所需的氩气，氩气通过碗口上沿的透气孔喷入碗口与钢包下水口之间，避免空气卷入长水口，在喷粉过程中也可以抑制钙蒸气外溢。
（2）打开喷粉载气（氩气），载气流量为1.5L/min，10s后打开钢包水口滑板，开始浇铸。
（3）钢包内的钢水经由长水口流入中间包，待中间包注流区的液面淹没长水口出口时，在喷粉载气流量不变的情况下开始喷吹钙粉，喷粉流量为0.06kg/min，固气比为22.4，所选钙粉的粒度为400目。
（4）在钢包浇铸结束前，首先停止喷粉，保持喷粉载气继续喷吹，然后关闭钢包水口滑板，停止浇铸，待长水口内没有钢流时，关闭喷粉载气，关闭密封所需氩气（浇铸过程一直存在），拆下长水口，准备下一包钢水的浇铸。
实施结果表明，浇铸所得钢坯中的平均[Ca]含量为0.0012%，钙粉的收得率可达60%，钢坯中的团簇状Al 2O 3夹杂物明显减少；而且，由于钙的收得率稳定，更容易实现精准钙处理，促进高熔点的Al 2O 3夹杂物转变为低熔点的12CaO·7Al 2O 3夹杂物，钢材质量得到明显改善。
同样的方法浇铸十包钢水，钙粉的收得率相差最大为2.5%，且夹杂物明显减少，钢材质量得到明显改善；说明本发明方法钙粉收得率高且稳定。
现有技术都是采用喂线法，钙镁收得率低且不稳定，现有钙镁收得率计算公式如下（以钙为例）：
Figure 737874dest_path_image001
。
现有技术公开的纯钙线处理收得率如下：
Figure 398663dest_path_image002
。
本发明克服了喂线法喷溅严重、收得率低且不稳定的缺陷，首创在浇铸过程中连续喷粉进行镁钙处理的方法，既能避免镁钙合金线中其他元素的影响，又能大幅提升镁钙收得率。

Claims (10)

  1. 利用长水口喷粉进行钢水镁钙处理的方法，包括以下步骤：在长水口碗口下方的内侧壁上设置狭缝式喷嘴；在钢水浇铸过程中，镁粉流或钙粉流由狭缝式喷嘴喷入长水口的内腔，完成钢水镁钙处理。
  2. 根据权利要求1所述利用长水口喷粉进行钢水镁钙处理的方法，其特征在于，长水口的碗口上表面设有密封材料；长水口的碗口上设有透气孔。
  3. 根据权利要求1所述利用长水口喷粉进行钢水镁钙处理的方法，其特征在于，所述狭缝式喷嘴与浸入式水口的内腔连通；狭缝式喷嘴通过输粉管道与喷粉***相连。
  4. 根据权利要求1所述利用长水口喷粉进行钢水镁钙处理的方法，其特征在于，镁粉流或钙粉流以氩气为载气。
  5. 根据权利要求1所述利用长水口喷粉进行钢水镁钙处理的方法，其特征在于，包括以下步骤：
    （1）将镁粉或者钙粉加入喷粉***内；
    （2）将长水口的碗口与钢包下水口对接，碗口上的透气孔喷吹氩气，打开喷粉载气，不喷吹镁粉或钙粉，然后打开钢包水口滑板，开始浇铸；
    （3）当中间包注流区的液面淹没长水口出口时，开始喷吹镁粉或钙粉；
    （4）在钢包浇铸结束前，停止喷吹镁粉或者钙粉，并保持打开喷粉载气；然后停止浇铸，当长水口内没有钢流时，关闭喷粉载气；完成钢水镁钙处理。
  6. 根据权利要求1所述利用长水口喷粉进行钢水镁钙处理的方法，其特征在于，狭缝式喷嘴的宽度为0.1～2mm。
  7. 钢水镁钙处理喷粉用长水口，包括长水口以及狭缝式喷嘴；所述长水口两端分别为长水口碗口、长水口出口；所述长水口内侧壁面上，碗口下方设置有狭缝式喷嘴。
  8. 基于长水口的钢水镁钙处理喷粉用装置，包括长水口以及狭缝式喷嘴；所述长水口两端分别为长水口碗口、长水口出口；所述长水口内侧壁面上，碗口下方设置有狭缝式喷嘴；狭缝式喷嘴通过输粉管道与喷粉***相连。
  9. 根据权利要求8所述基于长水口的钢水镁钙处理喷粉用装置，其特征在于，长水口碗口上表面设有密封材料；长水口碗口上设有透气孔。
  10. 权利要求8所述基于长水口的钢水镁钙处理喷粉用装置在钢水镁钙处理中的应用。
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CN111304407A (zh) * 2020-04-09 2020-06-19 苏州大学 一种利用长水口喷粉进行钢水镁钙处理的方法
CN111451462A (zh) * 2020-04-09 2020-07-28 苏州大学 利用浸入式水口喷吹镁粉细化连铸坯凝固组织的方法

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