WO2013060101A1

WO2013060101A1 - Method for smelting high-aluminum-low-silicon ultrapure ferritic stainless steel

Info

Publication number: WO2013060101A1
Application number: PCT/CN2012/070096
Authority: WO
Inventors: 徐迎铁; 陈兆平; 李实�
Original assignee: 宝山钢铁股份有限公司
Priority date: 2011-10-25
Filing date: 2012-01-06
Publication date: 2013-05-02
Also published as: IN2014CN01547A; CN102329920B; JP5833767B2; CN102329920A; JP2015501382A; EP2772554A1; EP2772554B1; KR101787179B1; EP2772554A4; KR20140092800A

Abstract

A method for smelting high-aluminum-low-silicon ultrapure ferritic stainless steel. First, vacuum oxygen decarburization (VOD) and free decarburization treatment is performed on molten ferritic stainless steel in a VOD furnace, then a reduction process of a VOD vacuum treatment process is improved, and measures such as preliminary deoxidation, final deoxidation, vacuum breaking, addition of high-density aluminum iron, control of the alkalinity of slag followed by wire feeding treatment, and protected casting in a continuous casting process are taken, so as to obtain high-aluminum-low-silicon ultrapure ferritic stainless steel during the continuous casting treatment, improve acid pickling performance of the ultrapure ferritic stainless steel, further improve the purity of the molten steel and the castable performance in the continuous casting process, meanwhile effectively suppress the formation of the harmful inclusion of the magnesia aluminum spinel, effectively remove the inclusion of Al₂O₃, suppress oxidation of titanium in titanium-containing steel, and avoid blockage of a tundish nozzle in the continuous casting process.

Description

一种高铝低硅超纯铁素体不锈钢的冶炼方法技术领域 Smelting method of high-aluminum low-silicon ultra-pure ferritic stainless steel

本发明涉及不锈钢冶炼领域，具体地，涉及一种铁素体不锈钢的冶炼方法，更具体地，涉及一种高铝低硅超纯铁素体不锈钢的冶炼方法。背景技术 The present invention relates to the field of stainless steel smelting, and in particular to a smelting method for ferritic stainless steel, and more particularly to a smelting method for high alumina low silicon ultra pure ferritic stainless steel. Background technique

超纯铁素体不锈钢是铁素体不锈钢的精品，一般要求碳氮总含量小于 150ppm，总氧含量低于 40ppm，且夹杂物的数量、尺寸和类型得到有效控制，且超纯铁素体不锈钢可部分替代奧氏体不锈钢，由于其不要求含镍元素，起到了节约镍资源的作用。超纯铁素体不锈钢的冶炼过程一般要经过真空吹氧脱碳炉（简称 VOD 炉）进行超真空条件下吹氧深脱碳、脱氮处理，所述 VOD炉的常规操作如下：一、经 AOD处理完的钢水用钢包运输进入 VOD处理工位，测定温度和成分，合格后进入真空处理室，先与丑真空并底搅拌；二、真空条件下开始吹氧脱碳处理，底搅拌条件下顶吹氧脱碳，根据炉气成分来判定是否终止吹氧，当炉气中 CO+CO₂含量低于一定值时，停止吹氧；三、超真空条件下自由脱碳处理，采用大搅拌；四、还原过程，加入硅铁、铝、石灰和萤石进行脱氧和硅的合金化处理；五、破真空；六、大气条件下喂丝并软搅拌，最后送浇铸。然而，在上述第二步的吹氧脱碳处理过程中，吹氧不能完全用于脱碳，有相当一部分氧要进入熔池以氧化铬或溶解氧的形式存在，所以在第三部自由脱碳过后，还要进行脱氧处理。其中，硅、铝是常用的脱氧元素。欧洲各钢铁公司最初采用的是纯硅脱氧技术，原因是采用铝脱氧会大量形成的 Α1₂Ο₃夹杂，进而对多数钢种产生不良影响，然而硅脱氧的钢中全氧含量非常高，铸坯中全氧在 60ppm以上，从而影响最终产品的性能。 Ultra-pure ferritic stainless steel is a fine product of ferritic stainless steel. It generally requires a total carbon and nitrogen content of less than 150ppm, a total oxygen content of less than 40ppm, and the number, size and type of inclusions are effectively controlled, and ultra-pure ferritic stainless steel. It can partially replace austenitic stainless steel, and it does not require nickel-containing elements, which plays a role in saving nickel resources. The smelting process of ultra-pure ferritic stainless steel is generally carried out by vacuum oxygen decarburization furnace (referred to as VOD furnace) for deep decarburization and denitrification under ultra-vacuum conditions. The conventional operation of the VOD furnace is as follows: The molten steel treated by AOD is transported into the VOD treatment station by ladle, and the temperature and composition are measured. After passing the test, it enters the vacuum processing chamber and is stirred with the ugly vacuum. Second, the oxygen decarburization treatment is started under vacuum conditions. The top blowing oxygen decarburization determines whether to terminate the oxygen blowing according to the composition of the furnace gas. When the CO+CO ₂ content in the furnace gas is lower than a certain value, the oxygen is stopped; 3. The free decarburization treatment under the ultra-vacuum condition, using the large stirring Fourth, the reduction process, adding ferrosilicon, aluminum, lime and fluorite for deoxidation and silicon alloying; Fifth, breaking the vacuum; Sixth, under the atmospheric conditions, the wire is fed with soft agitation, and finally sent to cast. However, in the oxygen blowing and decarburization treatment in the second step above, the oxygen blowing cannot be completely used for decarburization, and a considerable portion of the oxygen enters the molten pool in the form of chromium oxide or dissolved oxygen, so it is freely removed in the third part. After the carbon has passed, it is also deoxidized. Among them, silicon and aluminum are commonly used deoxidizing elements. European steel companies initially used pure silicon deoxidation technology because of the large amount of Α1 ₂ Ο ₃ inclusions formed by aluminum deoxidation, which adversely affects most steel grades. However, the oxygen content of silicon deoxidized steel is very high, casting The total oxygen in the billet is above 60ppm, from And affect the performance of the final product.

随着对超纯铁素体不锈钢的要求越来越高，需要其总氧含量也处于极低水平，人们开始尝试采用硅铝复合脱氧工艺，以进一步降低钢中氧含量，对于硅铝复合脱氧工艺，目前主要存在如下专利问下： As the demand for ultra-pure ferritic stainless steel is getting higher and higher, and the total oxygen content is required to be at an extremely low level, people have begun to try the silicon-aluminum composite deoxidation process to further reduce the oxygen content in the steel. At present, there are mainly the following patents:

日本发明号 JP2002030324(A)给出了硅铝复合脱氧冶炼防止条纹缺陷（也称瓦棱状缺陷）铁素体不锈钢的方法，脱氧过程先加入硅铁，目标硅含量控制在 0.20 3.0wt%，渣碱度（渣中 CaO与 SiO₂的质量比）控制在 1.2 2.4，最后用铝脱氧，要求钢液在浇铸前 A1含量与 Ti含量的比例在 0.01〜0.10之间，此方法可提高钢液在连铸过程的等轴晶率（即晶体凝固后其中形成等轴晶占全部结晶的百分率。如铸坯中心等轴晶率就是中心等轴晶区直径与铸坯直径百分比。 ) 达 60%，并很好地控制夹杂物成分，防止浇铸过程中间包水口堵塞，最终钢液全氧含量也保持在较低水平。然而，此专利渣碱度控制在 1.2〜2.4之间意味着渣的氧活性仍然很高，难以将钢液氧含量降低到极低水平。 Japanese invention No. JP2002030324 (A) gives a method for preventing streaking defects (also called rib-shaped defects) of ferritic stainless steel by silicon-aluminum composite deoxidation and smelting. The desiliconization process is first added with ferrosilicon, and the target silicon content is controlled at 0.20 3.0 wt%. The slag alkalinity (mass ratio of CaO to SiO ₂ in the slag) is controlled at 1.2 2.4. Finally, deoxidation with aluminum requires the ratio of A1 content to Ti content of the molten steel before casting to be between 0.01 and 0.10. This method can improve the molten steel. The equiaxed crystal ratio in the continuous casting process (that is, the percentage of the equiaxed crystals in the total crystals formed after the solidification of the crystal. For example, the equiaxed crystal ratio of the center of the billet is the diameter of the central equiaxed crystal region and the diameter of the billet.) Up to 60% , and control the composition of the inclusions well, to prevent blockage of the water in the middle of the casting process, and finally the total oxygen content of the molten steel is kept at a low level. However, the patented slag basicity controlled between 1.2 and 2.4 means that the oxygen activity of the slag is still high, and it is difficult to reduce the oxygen content of the molten steel to an extremely low level.

中国专利 CN101058837 , 专利名称：一种超纯铁素体不锈钢脱碳、脱氮的冶炼方法中，给出了一种超纯铁素体不锈钢的冶炼方法，钢液真空处理脱碳后，在真空条件下（真空度 5mbar ) ，先加入硅铁脱氧，再加入铝深脱氧，脱氧时间 5〜10分钟，然后再用合金微调，此脱氧方法处理时间短，脱氧效果不错，被广泛应用。 Chinese patent CN101058837, patent name: In a method of smelting decarburization and denitrification of ultra-pure ferritic stainless steel, a smelting method of ultra-pure ferritic stainless steel is given, after vacuum decarburization of molten steel, in vacuum Under the condition (vacuum degree 5 mbar), first add ferrosilicon deoxidation, then add aluminum deep deoxidation, deoxidation time 5~10 minutes, and then finely adjust with alloy. This deoxidation method has short processing time and good deoxidation effect, and is widely used.

然而 JP2002030324(A)和 CN 101058837并没有给出具体添加铝到钢液中的方法，由于铝块或铝粒密度大大低于钢液密度，在 VOD真空条件下直接加入将上浮在钢液上部与渣直接接触而反应并大量放热，很难有效进入钢液熔池进行沉淀脱氧，这就导致直接添加铝很难控制钢在处理结束后的铝含量，从而无法保证沉淀脱氧效果。 However, JP2002030324(A) and CN 101058837 do not give a specific method for adding aluminum to molten steel. Since the density of aluminum or aluminum particles is much lower than the density of molten steel, direct addition under VOD vacuum will float up on the upper part of the molten steel. The slag is directly contacted and reacts and emits a large amount of heat. It is difficult to effectively enter the molten steel bath for precipitation deoxidation, which results in the direct addition of aluminum, which is difficult to control the aluminum content of the steel after the treatment, and thus the precipitation deoxidation effect cannot be ensured.

同时，采用硅铝复合脱氧涉及的硅、铝元素最终含量对钢的脱氧效果、后工序处理以及钢的组织性能也有一定的影响，主要表现在：一）、如果钢中铝含量低，脱氧效果则不明显，即钢液中氧含量偏高，如果随后要喂钛处理，则会形成大量的氧化钛夹杂，大量的氧化钛夹杂可能会堵塞中间包水口；二）、最新研究表明，高硅含量（一般认为含量高于 0.3%) 的铁素体不锈钢在后工序酸洗难度大，影响了不锈钢产品表面光洁度。所以，为了进一步提高产品质量并保证生产顺利，对于很多超纯铁素体不锈钢品种，脱氧元素含量的控制朝着低硅、高铝方向发展，具体为硅含量要求小于 0.3%或更低，下限根据钢种其他要求确定，铝含量控制在 0.01〜0.1%的范围内，可有效地降低全氧含量，并能防止随后钛合金化过程钛的氧化。对于低硅、高铝超纯铁素体不锈钢的冶炼，前面也提到，相关专利以及常规方法不能在 VOD处理过程中有效地提高钢中铝含量到目标含量范围，同时，如果提高了铝含量，一旦炉渣碱度控制不合适，钢中硅含量也很难控制在合适范围内。如果仿照碳钢冶炼过程的铝脱氧方法，即通过喂铝丝来提高钢中铝含量，由于真空条件下喂丝难度太大，那么只能在真空处理结束并破真空后的非真空条件才能喂铝丝，这的确能提高钢中铝含量，然而，喂铝丝后不能再对不锈钢钢液进行大搅拌，生成的 Α1₂Ο₃夹杂很难迅速长大并排除，且非真空条件下喂铝丝会增大钢液吸氮的风险，并延长处理时间，所以，非真空条件下喂铝丝并不是科学方法。如果在真空条件下喷吹铝粉，可以实现提高钢中铝含量，但真空喷吹设备复杂，且控制难度很大。因此，现有技术和常规操作并没有能够切实解决在真空条件下提高钢中铝含量并有效控制硅含量的技术问题。发明内容 At the same time, the final content of silicon and aluminum involved in the deoxidation of silicon-aluminum composites is used to deoxidize the steel. The post-process treatment and the microstructure of the steel also have certain effects, mainly in: a), if the aluminum content in the steel is low, the deoxidation effect is not obvious, that is, the oxygen content in the molten steel is too high, if the titanium is subsequently treated, A large amount of titanium oxide inclusions will form, and a large amount of titanium oxide inclusions may block the tundish; 2) New research shows that ferritic stainless steel with high silicon content (generally considered to be higher than 0.3%) is difficult to pickle in the later process. Large, affecting the surface finish of stainless steel products. Therefore, in order to further improve product quality and ensure smooth production, for many ultra-pure ferritic stainless steel varieties, the control of deoxidizing element content is moving toward low silicon and high aluminum, specifically the silicon content requirement is less than 0.3% or lower, the lower limit. According to other requirements of steel grades, the aluminum content is controlled within the range of 0.01 to 0.1%, which can effectively reduce the total oxygen content and prevent the oxidation of titanium in the subsequent titanium alloying process. For the smelting of low-silicon, high-aluminum ultra-pure ferritic stainless steel, it is also mentioned above that related patents and conventional methods cannot effectively increase the aluminum content in the steel to the target content range during the VOD treatment, and at the same time, if the aluminum content is increased Once the slag basicity control is not suitable, the silicon content in the steel is also difficult to control within a suitable range. If the aluminum deoxidation method in the carbon steel smelting process is modeled, that is, the aluminum content in the steel is increased by feeding the aluminum wire, since the feeding of the wire under vacuum is too difficult, the non-vacuum condition can only be fed after the vacuum treatment is finished and the vacuum is broken. Aluminum wire, which does increase the aluminum content in the steel. However, after the aluminum wire is fed, the stainless steel liquid can no longer be stirred agitated, and the resulting Α1 ₂ Ο ₃ inclusions are difficult to grow and remove quickly, and the aluminum is fed under non-vacuum conditions. Filament increases the risk of nitrogen absorption by the molten steel and prolongs the processing time. Therefore, feeding aluminum wire under non-vacuum conditions is not a scientific method. If the aluminum powder is sprayed under vacuum conditions, the aluminum content in the steel can be increased, but the vacuum blowing equipment is complicated and the control is very difficult. Therefore, the prior art and conventional operations have not been able to effectively solve the technical problem of increasing the aluminum content in steel under vacuum conditions and effectively controlling the silicon content. Summary of the invention

为解决上述存在的问题，本发明的目的在于提供一种高铝低硅超纯铁素体不锈钢的冶炼方法，通过对 VOD真空处理过程的还原过程加以改进，加入高密度的铝铁、控制炉渣碱度、随后进行喂丝处理并在连铸过程采用保护浇铸等措施，实现从 VOD到连铸处理过程中冶炼出高铝低硅超纯铁素体不锈钢，提高超纯铁素体不锈钢的酸洗性能，并进一步提高钢水的纯净度和连铸过程的可浇铸性能，同时有效抑制有害夹杂物镁铝尖晶石的形成，有效去除 Α1₂Ο₃夹杂物，并在含钛钢中抑制了钛的氧化，避免了连铸过程的中间包水口堵塞。 In order to solve the above problems, the object of the present invention is to provide a high aluminum low silicon ultra-pure ferritic stainless steel smelting method, by improving the reduction process of the VOD vacuum process, adding High-density aluminum-iron, control of slag alkalinity, subsequent feeding process and protective casting in the continuous casting process to achieve high-alumina low-silicon ultra-pure ferritic stainless steel from VOD to continuous casting process Ultra-pure ferritic stainless steel pickling performance, and further improve the purity of molten steel and castability of continuous casting process, while effectively inhibiting the formation of harmful inclusions of magnesium-aluminum spinel, effectively removing Α1 ₂ Ο ₃ inclusions, And the oxidation of titanium is inhibited in the titanium-containing steel, and the blockage of the intermediate water in the continuous casting process is avoided.

为达到上述目的，本发明采取如下技术方案： In order to achieve the above object, the present invention adopts the following technical solutions:

本发明提供一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，包括如下步骤： The invention provides a method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel, which comprises the following steps:

( 1 ) 、将铁素体不锈钢钢液在 VOD炉内进行真空吹氧脱碳及自由脱碳处理，处理后得到的铁素体不锈钢钢液主要成分要求：铬质量百分含量 10-23%, 碳质量百分含量小于 0.01%，氮质量百分含量小于 0.01%; (1) The ferritic stainless steel liquid steel is subjected to vacuum oxygen decarburization and free decarburization treatment in the VOD furnace. The main components of the ferritic stainless steel molten steel obtained after the treatment are as follows: Chromium mass percentage 10-23% , the carbon content percentage is less than 0.01%, and the nitrogen mass percentage is less than 0.01%;

( 2 ) 、预脱氧：在经步骤（1 ) 处理后得到的铁素体不锈钢钢液中，加入硅铁和 /或铝块进行预脱氧处理，并加入石灰和萤石进行造渣，然后在高真空强搅拌条件下，处理时间 5~10min; (2) Pre-deoxidation: In the ferritic stainless steel molten steel obtained after the step (1) treatment, ferrosilicon and/or aluminum blocks are added for pre-deoxidation treatment, and lime and fluorite are added for slag formation, and then Under high vacuum and strong agitation conditions, the treatment time is 5~10min;

( 3 ) 、终脱氧：在经步骤（2 ) 处理后得到的铁素体不锈钢钢液中，加入铝铁进行终脱氧处理，所述铝铁中铝的质量百分含量为 20〜60%，并加入石灰和萤石进行造渣，接着在真空条件下，中强度搅拌 2〜5min，然后在高真空强搅拌条件下，处理 12〜18min; (3), final deoxidation: in the ferritic stainless steel molten steel obtained after the step (2) treatment, adding aluminum iron for final deoxidation treatment, the aluminum alloy has a mass percentage of 20 to 60%, And adding lime and fluorite for slagging, and then under vacuum, stirring at medium strength for 2~5min, and then under high vacuum and stirring, 12~18min;

( 4 ) 、破真空； (4), breaking the vacuum;

( 5 ) 、在常压条件下，将所述铁素体不锈钢钢液软搅拌 8〜10min，然后在常压条件下，向所述铁素体不锈钢钢液喂钙丝，喂钙丝结束后，软搅拌 5~10min; (5), under normal pressure conditions, the ferritic stainless steel liquid is softly stirred for 8 to 10 minutes, and then, under normal pressure, the calcium wire is fed to the ferritic stainless steel liquid, after the calcium wire is fed. , soft agitation 5~10min;

( 6 ) 、继续软搅拌 15〜30min，之后将铁素体不锈钢钢液在保护气氛中进行连铸，最终得到高铝低硅超纯铁素体不锈钢。 (6), continue soft agitation for 15~30min, then ferritic stainless steel in a protective atmosphere Continuous casting is carried out to obtain high-aluminum low-silicon ultra-pure ferritic stainless steel.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，步骤（2 ) 中，所述硅铁和 /或铝块总加入量为 4〜9kg/t，所述硅铁中硅的质量百分含量为 70〜80%，所述石灰加入质量取值为如下两个范围中的较大值：硅铁加入质量的 4〜6倍或铝块加入质量的 2〜3倍；所述萤石加入质量为石灰加入质量的 0.05〜0.3倍，经步骤（2 ) 处理后，所述铁素体不锈钢钢液中硅的质量含量小于 0. 1%、大于 0，要求氧的质量含量大于 0.01%。 According to the present invention, a method for smelting a high-alumina low-silicon ultra-pure ferritic stainless steel, in the step (2), the total amount of the ferrosilicon and/or aluminum block is 4 to 9 kg/t, The mass percentage of silicon in the ferrosilicon is 70-80%, and the mass of the lime added is the larger of the following two ranges: 4 to 6 times the mass of the ferrosilicon or the mass of the aluminum block. 1%以上 greater than 0. The mass content of silicon in the ferritic stainless steel liquid is less than 0.1%, greater than 0. The mass of the ferritic stainless steel liquid is less than 0.1%, greater than 0. The oxygen content is required to be greater than 0.01%.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，步骤（3 ) 中，所述铝铁中纯铝的加入量为 2〜6kg/t，所述石灰的加入量为铝铁中纯铝加入量的 2〜3倍，萤石加入量为石灰加入质量的 0.05〜0.3倍，经步骤（3 ) 处理后，所述铁素体不锈钢钢液中硅的质量含量小于 0.3%、大于 0，铝的质量含量为 0.01〜0. 1%，氧的质量含量小于 0.003%。 According to the present invention, a method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel is provided, wherein, in step (3), the amount of pure aluminum added to the aluminum-iron is 2 to 6 kg/t, The amount of lime added is 2 to 3 times of the amount of pure aluminum added in the aluminum iron, and the amount of fluorite added is 0.05 to 0.3 times the mass of the lime added. After the step (3), the silicon in the ferritic stainless steel liquid is The mass content of the aluminum is less than 0.3%, greater than 0, and the mass content of aluminum is 0.01 to 0.1%, and the mass content of oxygen is less than 0.003%.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，在步骤（5 ) 中，所述喂钙丝为向铁素体不锈钢钢液中喂入纯钙丝，所述纯钙丝喂入量为 0. 1〜0.3kg/t，经步骤（5 ) 处理后，所述铁素体不锈钢钢液中钙的质量含量为 15~30ppm。 According to the present invention, a method for smelting a high-alumina low-silicon ultra-pure ferritic stainless steel, in the step (5), the calcium-feeding wire is fed with pure calcium into a ferritic stainless steel molten steel. The amount of calcium in the ferritic stainless steel molten steel is 15 to 30 ppm after the step (5).

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，在步骤（5 ) 中，喂完钙丝并软搅拌后，向铁素体不锈钢钢液中喂入钛丝，所述钛丝中的纯钛量为 l~3kg/t。 According to the present invention, a high aluminum low silicon ultra-pure ferritic stainless steel smelting method is adopted. In the step (5), after feeding the calcium wire and softly stirring, feeding to the ferritic stainless steel molten steel The titanium wire is inserted into the titanium wire, and the amount of pure titanium in the titanium wire is 1-3 kg/t.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，在最终所制得的高铝低硅超纯铁素体不锈钢中，硅质量百分含量小于 0.3%，铝质量百分含量为 0.01 0. 1%。 According to the present invention, a method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel is adopted, wherein in the finally obtained high-aluminum low-silicon ultra-pure ferritic stainless steel, the silicon mass percentage is less than 0.3. %%。 The mass percentage of aluminum is 0.01 0.1%.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，步骤（2 ) 中，当要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值为 0.3%时，全部加入硅铁； A method for smelting a high-aluminum low-silicon ultra-pure ferritic stainless steel according to the present invention, wherein, in step (2), When the upper limit of the silicon mass content of the high-alumina low-silicon ultra-pure ferritic stainless steel finally required is 0.3%, all of the ferrosilicon is added;

当要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值低于或者等于 0.2%时，全部加入铝块； When the upper limit of the mass content of silicon in the high-aluminum low-silicon ultra-pure ferritic stainless steel finally required is less than or equal to 0.2%, all aluminum blocks are added;

当要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值在 0.2〜0.3%之间时，加入硅铁和铝块，所述硅铁和铝块的加入比例 = (最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值 - 0.2%) I ( 0.3% -最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值）。 When the upper limit value of the silicon mass content in the finally obtained high-aluminum low-silicon ultra-pure ferritic stainless steel is required to be between 0.2 and 0.3%, ferrosilicon and aluminum blocks are added, and the proportion of the ferrosilicon and aluminum blocks is added. = (The upper limit of the mass content of silicon in the final high-alumina low-silica ultra-pure ferritic stainless steel - 0.2%) I (0.3% - the quality of silicon in the final high-alumina low-silica ultra-pure ferritic stainless steel The upper limit of the content).

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是，步骤（3 ) 中，所述铝铁形状为块状或球状，密度为 4.5〜6.5g/cm³，直径 3〜6cm; 经步骤（3 )处理后，炉渣中 CaO与 SiO₂的质量比高于 2.8，炉渣中 CaO 与 Α1₂Ο₃的质量比高于 1。 According to the present invention, a method for smelting a high-alumina low-silicon ultra-pure ferritic stainless steel is provided. In the step (3), the aluminum-iron is in the form of a block or a sphere, and has a density of 4.5 to 6.5 g/cm. ³ , diameter ³ ~6cm; after the step (3), the mass ratio of CaO to SiO ₂ in the slag is higher than 2.8, and the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag is higher than 1.

根据本发明提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，采用的是， According to the present invention, a method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel is adopted,

所述高真空强搅拌的条件为：真空压力控制在 800Pa以下， VOD炉底部吹氩流量控制在 4~8 L/(min* t)之间； The high vacuum strong agitation condition is: the vacuum pressure is controlled below 800 Pa, and the argon flow rate at the bottom of the VOD furnace is controlled between 4 and 8 L/(min* t);

所述中强度搅拌的条件为：真空压力控制在 2000Pa以下， VOD炉底部吹氩流量控制在 1~4 L/(min* t)之间； The medium-strength agitation condition is: the vacuum pressure is controlled below 2000 Pa, and the argon flow rate at the bottom of the VOD furnace is controlled between 1 and 4 L/(min* t);

所述软搅拌的条件为：在常压条件下， VOD炉底部吹氩流量控制 l~5L/(min* t)之间。 The conditions of the soft agitation are: under normal pressure conditions, the flow rate of argon blowing at the bottom of the VOD furnace is between l~5L/(min*t).

本发明所提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法有益效果在于： The smelting method of the high aluminum low silicon ultra pure ferritic stainless steel provided by the invention has the beneficial effects of:

1、可在 VOD冶炼过程中有效地提高铝沉淀脱氧效率，有效地提高钢中铝含量，并防止渣中硅元素返回到钢液中，以控制硅含量处于较低水平，实现了高铝低硅含量超纯铁素体不锈钢的冶炼； 1. It can effectively improve the deoxidation efficiency of aluminum precipitation in the VOD smelting process, effectively increase the aluminum content in the steel, and prevent the silicon element in the slag from returning to the molten steel to control the silicon content at a lower level. Smelting of high-aluminum and low-silicon content ultra-pure ferritic stainless steel;

2、连铸过程采用保护浇铸措施，可防止高铝含量钢液的二次氧化，结合钙处理，可避免中间包水口的堵塞；再者，由于在 VOD过程就实现了铝脱氧效果和铝含量目标控制，生成的 Α1₂Ο₃夹杂在 VOD大搅拌过程可充分长大，破真空后能有效上浮，进而提高了钢水的纯净度； 2. The continuous casting process adopts protective casting measures to prevent secondary oxidation of high aluminum content molten steel. Combined with calcium treatment, it can avoid the blockage of the tundish water inlet; furthermore, aluminum deoxidation effect and aluminum content are realized in the VOD process. Target control, the generated Α1 ₂ Ο ₃ inclusions can be fully grown in the VOD large mixing process, and can effectively float after breaking the vacuum, thereby improving the purity of the molten steel;

3、由于所加高密度铝铁的铝能充分进入钢液，大大减小了其与渣中 MgO 直接反应生成镁铝尖晶石的概率，有效抑制有害夹杂物镁铝尖晶石的形成， Α1₂Ο₃夹杂的有效去除和抑制镁铝尖晶石的形成同样可避免中间包水口的堵塞； 4、由于铝含量的提升，如钢种需要钛合金化，则在喂钛过程中可大大抑制钛的氧化，可提高钛的收得率，本发明对防止由于氧化钛引起的水口堵塞有积极作用； 3. Since the aluminum added with high-density aluminum-iron can fully enter the molten steel, the probability of directly reacting with MgO in the slag to form magnesium-aluminum spinel is greatly reduced, and the formation of the harmful inclusion magnesium-aluminum spinel is effectively suppressed.有效_{1 2} Ο ₃ The effective removal of inclusions and the inhibition of the formation of magnesium-aluminum spinel can also avoid the blockage of the tundish; 4, due to the increase of aluminum content, such as the need for titanium alloying of steel, it can be greatly improved in the process of feeding titanium. Inhibiting the oxidation of titanium, the yield of titanium can be improved, and the present invention has a positive effect on preventing clogging of the nozzle due to titanium oxide;

5、本发明设计的方法安全可靠，可操作性能强，能大大提高冶炼的稳定性和产品质量。具体实施方式 5. The method designed by the invention is safe and reliable, has strong operability, and can greatly improve the stability of smelting and product quality. detailed description

本发明的工艺原理如下：一、本发明要求冶炼超纯铁素体不锈钢的目标硅、铝含量为：硅质量百分含量小于 0.3%，铝质量百分含量在 0.01〜0. 1%之间的目的在于：硅含量要求小于 0.3%主要是为了提高此不锈钢的酸洗性能，如果硅含量高于 0.3%，则钢的酸洗难度变大，影响了钢的光洁度，另外，此含量范围的硅可确保钢的靭性，提高其加工性能；铝质量要求在 0.01〜0. 1%之间，主要是从脱氧效果来考虑的，经过热力学计算， 1550 °C条件下，对于不同 Cr含量的铁素体不锈钢液， A1含量为 0.01%对应的溶解氧范围为 0.002〜0.0025% (；即 20~25ppm) ,由于全氧中还包含有夹杂物，所以，当铸坯中全氧要求小于 30ppm 的条件下，本专利涉及的铝含量要求高于 0.01%; 同时，铝含量上限为 0. 1%，主要考虑针对一些含钛钢种，需要保证铝-钛含量比大于 0.15，铝含量上限为 0.1%可保证钛含量可设计上限为 0.7%, 当然，如果铝含量超过 0.1%，冶炼成本变大，且没有必要。 Between the 0.01% and 0.1%, the content of the aluminum content is between 0.01% and 0.1%, and the content of the aluminum is between 0.01% and 0.1%. The purpose of the silicon content is less than 0.3%, mainly to improve the pickling performance of the stainless steel. If the silicon content is higher than 0.3%, the pickling difficulty of the steel becomes large, which affects the smoothness of the steel. In addition, the content range is Silicon can ensure the toughness of steel and improve its processing performance. The quality of aluminum is between 0.01~0.1%, mainly considering the deoxidation effect. After thermodynamic calculation, under the condition of 1550 °C, iron with different Cr content The body-made stainless steel solution has an A1 content of 0.01% and a dissolved oxygen range of 0.002 to 0.0025% (ie, 20 to 25 ppm). Since the inclusions are contained in the total oxygen, the total oxygen requirement in the slab is less than 30 ppm. 1%, The upper limit of the aluminum content is 0.1%, The main consideration is that for some titanium-containing steels, it is necessary to ensure that the aluminum-titanium content ratio is greater than 0.15, and the upper limit of aluminum content is 0.1% to ensure that the titanium content can be designed with an upper limit of 0.7%. Of course, if the aluminum content exceeds 0.1%, the smelting cost becomes large. And not necessary.

二、预脱氧和终脱氧： Second, pre-deoxidation and final deoxygenation:

对于如上硅铝含量范围的铁素体不锈钢的冶炼，本发明采用先用硅铁和铝块进行预脱氧，再加铝铁进行终脱氧，如步骤（2 ) 和（3 ) 所示。本发明还要求采用加硅铁、铝块和铝铁进行脱氧的方式，原因在于，如果整个脱氧过程只加入铝铁，由于铝铁成本较硅铁高，则整个冶炼成本会提升，且容易造成增碳严重；如果只加入硅铁和铝块，由于铝块轻，不能有效进入钢液，则不能完成提高钢中铝含量的目的；而如果硅铁、铝块和铝铁一起加入实现终脱氧，由于铝与氧的结合能力远大于硅与氧的结合力，在渣中 Cr₂O₃被基本还原的情况下，铝会与 SiO₂发生强烈反应，导致钢中硅含量快速升高，很有可能不能满足终点硅含量小于 0.3%的要求。所以，本发明采用先加硅铁和部分铝块进行预脱氧的方式，预脱氧过程中，钢中氧含量并不能降到很低，根据硅、氧平衡的热力学公式，预脱氧过程硅元素可大量地与氧反应，从而保证了处理过程钢中硅含量处于较低值范围。预脱氧处理过后，加入铝铁进行终脱氧，由于铝铁的密度要高于纯铝块很多，则铝铁可以保证进入钢液熔池后大部分能沉在钢液中，熔化后释放的铝则可先进入钢液，实现有效的沉淀脱氧，并有效地提高钢中铝含量，当然，还会有部分熔化后的铝会直接进入渣中进行反应，但此并不妨碍钢中铝含量的快速提升。 For the smelting of ferritic stainless steel having the above silicon-aluminum content range, the present invention employs pre-deoxidation using ferrosilicon and aluminum blocks, followed by aluminum-iron for final deoxidation, as shown in steps (2) and (3). The invention also requires a method of deoxidizing by adding ferrosilicon, aluminum block and aluminum iron, because if only aluminum iron is added in the whole deoxidation process, since the cost of aluminum iron is higher than that of ferrosilicon, the whole smelting cost will increase, and it is easy to cause If the addition of ferrosilicon and aluminum blocks is only possible, because the aluminum block is light and cannot effectively enter the molten steel, the purpose of increasing the aluminum content in the steel cannot be completed; and if the ferrosilicon, aluminum block and aluminum-iron are added together to achieve the final deoxidation Since the bonding ability of aluminum and oxygen is much greater than the bonding force of silicon and oxygen, in the case where Cr ₂ O ₃ is substantially reduced in the slag, aluminum reacts strongly with SiO ₂ , resulting in a rapid increase in silicon content in the steel. It may not be possible to meet the requirement that the end silicon content be less than 0.3%. Therefore, the present invention adopts a method of pre-deoxidizing by first adding ferrosilicon and a part of aluminum block. In the process of pre-deoxidation, the oxygen content in the steel cannot be lowered to a very low level. According to the thermodynamic formula of silicon and oxygen balance, the pre-deoxidation process can be silicon element. A large amount of reaction with oxygen ensures that the silicon content of the steel in the process is in a lower range. After the pre-deoxidation treatment, aluminum iron is added for final deoxidation. Since the density of aluminum iron is much higher than that of pure aluminum, the aluminum iron can ensure that most of the aluminum can sink into the molten steel after entering the molten steel bath, and the aluminum released after melting. Then it can enter the molten steel first, realize effective precipitation deoxidation, and effectively increase the aluminum content in the steel. Of course, some of the molten aluminum will directly enter the slag for reaction, but this does not hinder the aluminum content in the steel. Rapid improvement.

1 ) 、预脱氧 1), pre-deoxidation

本发明步骤（2 ) 预脱氧，加硅含量质量百分比为 70〜80%的硅铁和 /或铝块进行预脱氧处理，硅铁和 /或铝块总加入量为 4〜9kg/t，并加石灰和萤石进行造渣，石灰加入质量为硅铁加入质量的 4〜6倍与铝块加入量的 2〜3倍中的较大值，萤石加入质量为石灰加入质量的 0.05〜0.3倍，高真空强搅拌条件下处理时间 5~10min，处理结束后要求硅质量含量小于 0.1%，氧质量含量大于 0.01%。 Step (2) pre-deoxidation of the present invention, adding a silicon iron and/or aluminum block having a silicon content of 70% to 80% by mass for pre-deoxidation treatment, and the total amount of ferrosilicon and/or aluminum block is 4 to 9 kg/t, and Adding lime and fluorite to slag, the quality of the lime added is 4 to 6 times the mass of ferrosilicon and 2 to 3 times the amount of aluminum added. The value of fluorite is 0.05~0.3 times of the mass of lime added, and the treatment time is 5~10min under high vacuum and strong stirring. After the treatment, the silicon content is less than 0.1% and the oxygen content is more than 0.01%.

此步骤前，钢液刚经过了吹氧脱碳的处理，熔池中有大量的溶解氧和氧化铬，加硅铁和铝块进行预脱氧的目的是要利用硅铁或铝块将氧化铬中的铬还原出，而尽量不降低钢中的氧含量，铝块具有很强的还原能力，可直接与渣中 Cr₂O₃反应，这里主要讨论硅的还原能力，硅还原反应方程如下： Before this step, the molten steel has just been subjected to oxygen decarburization treatment. There is a large amount of dissolved oxygen and chromium oxide in the molten pool. The purpose of pre-deoxidation with ferrosilicon and aluminum blocks is to use chromium iron or aluminum blocks to chrome oxide. The chromium in the reduction is reduced, and the oxygen content in the steel is not reduced as much as possible. The aluminum block has a strong reducing ability and can directly react with Cr ₂ O _{3 in the} slag. Here, the reduction ability of silicon is mainly discussed. The silicon reduction reaction equation is as follows:

1.5[Si] + (Cr₂O₃)=2[Cr]+1.5(SiO₂) 1.5[Si] + (Cr ₂ O ₃ )=2[Cr]+1.5(SiO ₂ )

经过热力学计算，假定氧化物 (Cr₂O₃)和（SiO₂)的以纯物质为标准的热力学活度均为 1，计算得出在铬含量为 18%的不锈钢中，硅含量需要大于 0.6%才能促使反应正向进行，这就意味着硅铁的密度不能太大，要确保硅铁上浮在钢液上方直接与渣中的 (； Cr₂O₃)进行反应，保证与渣接触的钢液局部硅含量大于 0.6%，由此，本专利选择常用的硅铁，其硅含量为 70〜80%，可满足硅铁密度不太高的要求，当然，随着石灰的熔化，渣相中 SiO₂活度降低，也加快了硅进行预脱氧。本发明之所以还选择铝进行预脱氧，主要是针对目标硅含量要求更低的一些钢种，文后有进一步的论述。由于含 75%硅的硅铁与等重量的铝块脱氧量接近于 1，所以对于硅铁和铝块加入量范围，当钢中铬含量低同时初始碳含量也低的情况，需要硅铁和铝块加入总量是比较少的，相反，钢中铬含量高同时初始碳含量也高，需要硅铁和铝块总量是比较多的，以下以两种在生产中可能出现的极端情况作为分析的例子，以此确定硅铁和铝块加入总量的范围。经过计算，对于低铬含量的铁素体不锈钢冶炼，如铬含量为 11.6%的钢种，钢水进入 VOD 前初始碳为 0.3%条件下，吨钢吹氧量大约 7Nm³/t可在真空条件下将碳脱除，根据以往经验，约有 30〜40%的氧会氧化铬形成 Cr₂O₃，则需要大约 2.6〜3.45kg的纯硅或 3.5〜4.6kg纯铝，考虑到硅铁中硅的含量，本发明设定需求硅铁和铝块总量的下限值为 4kg/t，而对于高铬钢的冶炼，如铬含量为 22.6%的钢种，进入 VOD前初始碳为 0.6% 的情况下，吨钢吹氧量大约 13Nm³/t可在真空条件下将碳脱除，根据以往经验，约有 35〜45% 的氧会氧化铬形成 Cr₂O₃，则需要大约 5.6〜7.24kg的纯硅或 7.5〜9.7kg 的纯铝，考虑到硅铁中硅的含量，本发明设定需求硅铁和铝块总加入量的上限值为 9kg/t。石灰的加入量是根据生成的 SiO₂ 量来确定的，要满足碱度要求的范围，本发明确定石灰加入质量为硅铁加入质量的 4〜6倍与铝块加入量的 2〜3倍中的较大值，可满足炉渣碱度控制在 2.8以上的范围，炉渣中 CaO与 Α1₂Ο₃的质量比例高于 1。对于萤石的加入，主要目的是加快石灰的溶解和熔化，其加入量要根据石灰本身熔化的难易程度确定，根据生产经验，确定萤石加入质量为石灰加入质量的 0.05〜0.3倍。由于步骤（2 ) 中加入的硅铁和铝块并不明显地降低钢中溶解氧含量，并要求氧含量大于 0.01%，可以确保反应过后钢中硅含量小于 0.1%。本步骤虽然规定了硅铁和铝块总加入量的范围，在实际执行过程中，还要根据冶炼过程的脱碳过程所吹氧气在脱碳、二次燃烧、损失、进入熔池的具体分配比例来确定硅铁和铝块需脱去的氧量，由于脱碳量是已知的，二次燃烧率可根据炉气成分分析出，损失量也可根据历史数据回归出，则氧气进入熔池的比例是可以计算得出的，由此可计算出硅铁和铝块总加入量的具体值，此值在本发明确定的范围内。 After thermodynamic calculations, it is assumed that the thermodynamic activities of the oxides (Cr ₂ O ₃ ) and (SiO ₂ ) are 1 based on pure substances. It is calculated that in stainless steel with a chromium content of 18%, the silicon content needs to be greater than 0.6%. In order to promote the reaction forward, this means that the density of ferrosilicon should not be too large, to ensure that the ferrosilicon floats above the molten steel and react directly with the slag (Cr ₂ O ₃ ) to ensure the molten steel in contact with the slag. The local silicon content is greater than 0.6%. Therefore, the silicon iron commonly used in this patent has a silicon content of 70 to 80%, which can meet the requirement that the ferrosilicon density is not too high. Of course, with the melting of lime, the SiO in the slag phase _{2 The} activity is reduced, which also accelerates the pre-deoxidation of silicon. The reason why the invention also selects aluminum for pre-deoxidation is mainly for some steel grades with lower target silicon content, which will be further discussed later. Since the deoxidization amount of the silicon iron containing 75% silicon and the aluminum block of equal weight is close to 1, the range of the amount of ferrosilicon and aluminum block is required, and when the chromium content in the steel is low and the initial carbon content is also low, ferrosilicon and The total amount of aluminum is relatively small. On the contrary, the chromium content in steel is high and the initial carbon content is also high. The total amount of ferrosilicon and aluminum blocks is required. The following two extreme situations may occur in production. An example of analysis to determine the extent to which the ferrosilicon and aluminum blocks are added. After calculation, for low chromium content ferritic stainless steel smelting, such as steel with a chromium content of 11.6%, the initial carbon of the molten steel before entering VOD is 0.3%, and the oxygen per ton of steel is about 7Nm ³ /t. Under the carbon removal, according to past experience, about 30~40% of oxygen will chrome oxide to form Cr ₂ O ₃ , then about 2.6~3.45kg of pure silicon or 3.5~4.6kg of pure aluminum is needed, considering the ferrosilicon The content of silicon, the lower limit of the total amount of ferrosilicon and aluminum blocks required by the present invention is 4 kg/t, and for high chromium steel Smelting, such as a steel with a chromium content of 22.6%, with an initial carbon of 0.6% before VOD, the oxygen per ton of steel is about 13Nm ³ /t, which can be removed under vacuum. According to past experience, 35~45% of oxygen will oxidize chromium to form Cr ₂ O ₃ , then about 5.6~7.24kg of pure silicon or 7.5~9.7kg of pure aluminum is needed. Considering the content of silicon in ferrosilicon, the present invention sets the demand for ferrosilicon The upper limit of the total amount of aluminum and aluminum is 9kg/t. The amount of lime added is determined according to the amount of SiO ₂ produced. To meet the range of alkalinity requirements, the present invention determines that the lime addition mass is 4 to 6 times the mass of the ferrosilicon and 2 to 3 times the amount of the aluminum block. The larger value can satisfy the range of slag basicity control above 2.8, and the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag is higher than 1. For the addition of fluorite, the main purpose is to accelerate the dissolution and melting of lime. The amount of lime added is determined according to the difficulty of melting the lime itself. According to the production experience, the quality of the fluorite is determined to be 0.05 to 0.3 times the mass of the lime added. Since the ferrosilicon and aluminum blocks added in the step (2) do not significantly reduce the dissolved oxygen content in the steel and require an oxygen content of more than 0.01%, it is ensured that the silicon content in the steel after the reaction is less than 0.1%. Although this step stipulates the total amount of ferrosilicon and aluminum blocks to be added, in the actual implementation process, according to the decarburization process of the smelting process, the specific distribution of oxygen in the decarburization, secondary combustion, loss, and entering the molten pool. The ratio determines the amount of oxygen that needs to be removed from the ferrosilicon and aluminum blocks. Since the amount of decarburization is known, the secondary combustion rate can be analyzed according to the composition of the furnace gas, and the amount of loss can also be returned based on historical data. The ratio of the pool can be calculated, whereby the specific value of the total amount of ferrosilicon and aluminum blocks added can be calculated, which is within the range determined by the present invention.

本发明对于步骤（2 ) ，还要求确定涉及的硅铁和 /或铝块的加入比例： a、如果要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量（即目标硅含量）上限为 0.3% 时，全部加入硅铁； For the step (2), the present invention also requires determining the proportion of the involved ferrosilicon and/or aluminum block: a. If the silicon content of the high-aluminum low-silicon ultra-pure ferritic stainless steel finally obtained is required (ie, the target silicon) When the upper limit is 0.3%, all of the ferrosilicon is added;

b、如果要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量上限要求更低，即当上限值低于 0.2% (包括 0.2%) 时，要求全部加入铝块； b. If the upper limit of the silicon content of the high-alumina low-silicon ultra-pure ferritic stainless steel required to be finally produced is required to be lower, that is, when the upper limit is less than 0.2% (including 0.2%), all aluminum blocks are required to be added;

c、当要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量上限为在 0.2〜0.3%之间时，硅铁和铝块的加入比例= (最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值 - 0.2% ) I ( 0.3% -最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值）。 c. When the upper limit of silicon mass content in the high-alumina low-silicon ultra-pure ferritic stainless steel that is finally required is between 0.2 and 0.3%, the proportion of ferrosilicon and aluminum block is added = (the final high aluminum content is low) Silicon ultrapure ferrite The upper limit of the mass content of silicon in stainless steel - 0.2%) I (0.3% - the upper limit of the mass content of silicon in the finally obtained high-aluminum low-silicon ultra-pure ferritic stainless steel).

其中，所述最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值表示硅含量不能超过的值。 Wherein, the upper limit value of the silicon mass content in the finally obtained high-aluminum low-silicon ultra-pure ferritic stainless steel indicates a value that the silicon content cannot exceed.

本发明之所以还选择铝进行预脱氧，主要是针对目标硅含量要求更低的一些钢种，当目标硅含量仅要求小于 0.3%时候，此处全部加硅铁并通过其后的碱度控制可实现这一目标，然而，如果目标硅含量要求小于 0.2%，考虑到终脱氧过程也会形成一定的增硅量，大约在 0. 1〜0.2%左右，则此处如果加硅铁形成增硅就不能满足最终硅含量小于 0.2%的要求，所以，这种情况要求全部加铝，对于目标硅质量含量上限值在 0.2〜0.3%之间，本发明设计硅铁和铝块混加，具体比例根据目标硅含量上限值要求确定，可满足要求。 The reason why the invention also selects aluminum for pre-deoxidation is mainly for some steel grades with lower target silicon content. When the target silicon content is only required to be less than 0.3%, all the ferrosilicon is added here and the alkalinity is controlled thereafter. This can be achieved. However, if the target silicon content is required to be less than 0.2%, a certain amount of silicon is formed in consideration of the final deoxidation process, which is about 0.1 to 0.2%. Silicon can not meet the requirement of the final silicon content less than 0.2%. Therefore, this situation requires all aluminum addition. For the target silicon mass content upper limit value is between 0.2% and 0.3%, the present invention designs a mixture of ferrosilicon and aluminum blocks. The specific ratio is determined according to the upper limit of the target silicon content and can meet the requirements.

2 ) 、终脱氧 2), final deoxygenation

本发明的步骤（3 ) 终脱氧过程，加入铝铁进行终脱氧处理，铝铁含铝质量百分含量 20〜60%,，碳质量含量小于 0. 1%，其余为铁和一些微量杂质元素，铝铁中纯铝的加入量 2〜6kg/t，并补加石灰和萤石，石灰补加量为铝铁中纯铝量的 2〜3倍，萤石加入质量为石灰加入质量的 0.05〜0.3倍，物料加入后先在真空条件下中强度搅拌 2〜5min，然后高真空强搅拌条件下处理 12〜18min，处理结束后可保证硅质量含量小于 0.3%, 铝质量含量 0.01〜0. 1%, 氧质量含量小于 0.003%。 The step (3) of the present invention, the final deoxidation process, adding aluminum iron for the final deoxidation treatment, the aluminum alloy containing aluminum mass percentage of 20~60%, the carbon mass content is less than 0.1%, the rest is iron and some trace impurity elements , the amount of pure aluminum in aluminum-iron is 2~6kg/t, and lime and fluorite are added. The amount of lime added is 2~3 times of the amount of pure aluminum in aluminum-iron. The quality of fluorite is 0.05. ~0.3 times, after the material is added, the medium is stirred under vacuum for 2~5min, then treated under high vacuum and stirred for 12~18min. After the treatment, the silicon content is less than 0.3%, and the aluminum content is 0.01~0. 1%, the oxygen content is less than 0.003%.

选择用密度相对高的铝铁作为终脱氧的脱氧剂，正如前面所论述，铝铁加入后，其包含的铝可以进入钢液熔池，而不象纯铝那样加入后大量地与渣中氧化物反应而基本不进入钢液熔池，生产实践已经证明了这一点，选择铝铁中铝质量百分含量 20〜60%除了满足密度要求范围外，还考虑了如果铝含量低于 20%，则含铁过大，由于本发明对纯铝的加入量是有要求的，则会导致铝铁本身加入量过大，不仅会导致增碳量增大，而且会导致熔池温降过大，经计算 lkg铝参加反应释放的能量可满足约 4kg铁从室温加热到钢水当前的 1700 °C，由此，确定铝铁终铝含量应高于 20%，铝铁中铝含量低于 60%主要从密度控制要求考虑的，铝铁要求密度高于 4.5g/cm³，对应铝含量为 60%。要求铝铁中碳含量小于 0.01%，主要是从控制增碳的方面考虑的，由于冶炼钢种为超低碳钢，应该控制铝铁加入后增碳越小越好，对于铝铁含碳为 0.1%的情况，吨钢加铝铁量 10kg的情况下，钢液增碳量为 10ppm，这基本还是可以接受的，所以要求铝铁中含碳量应小于 0.1%，这也是铝铁生产可实现的碳含量范围。铝铁的加入量按其中的纯铝来计，本发明要求纯铝加入量在 2〜6kg/t，铝加入不仅要脱去钢中的溶解氧，还要进一步还原预脱氧过程硅铁没能去除的渣中 Cr₂O₃，约消耗纯铝 0.5〜2.4kg/t，并有可能与渣中 SiO₂进一步反应，导致的回硅量 0.1%〜0.2%，约消耗纯铝 1.4〜2.6kg/t，另外还满足最终铝含量的目标 0.01〜0.1%，约消耗纯铝 0.1〜lkg/t，将如上下限值相加和上限值相加，得出纯铝加入量的范围 2〜6kg/t，铝铁加入量为纯铝加入量除以其含铝量。补加石灰的目的是继续保证炉渣中 CaO与 Α1₂Ο₃的质量比例。本发明要求此步骤物料加入后先在真空条件下中强度搅拌 2〜5min，其目的是一方面要求对钢液有一定强度的搅拌，促使铝进入钢液，另一方面，如果搅拌强度过大，会把铝铁喷到渣面上，导致铝进入不了钢液中，所以，这里采取中强度搅拌。本步骤要求高真空强搅拌处理时间 12〜18***要要保证充分的时间让 Α1₂Ο₃夹杂长大，才能在其后的大气条件下的软搅拌过程充分上浮得以去除。另外，需要指出的是，由于铝铁中的铝可以充分进入钢液，在脱氧到一定程度时，避免了铝直接进入渣中去还原渣中的 MgO，从而大大制约了镁铝尖晶石的形成，对于不锈钢，镁铝尖晶石是非常有害的夹杂物，会导致产品缺陷。正因为采用铝铁实现了铝的控制和硅的控制，处理结束后可保证硅质量含量小于 0.3%, 铝质量含量 0.01 0.1%, 氧质量含量小于 0.003%。 Aluminium iron with a relatively high density is selected as the final deoxidizing deoxidizer. As discussed above, after the aluminum iron is added, the aluminum contained therein can enter the molten steel bath, instead of being oxidized in a large amount with the slag after being added like pure aluminum. The material reaction does not basically enter the molten steel bath. The production practice has proved this point. The selection of aluminum content in the aluminum alloy is 20~60%, in addition to meeting the density requirements, it is also considered if the aluminum content is less than 20%. If the iron content is too large, since the amount of pure aluminum added in the present invention is required, it will result in If the amount of aluminum-iron itself is too large, it will not only lead to an increase in carbon increase, but also cause the temperature drop of the molten pool to be too large. The energy released by the reaction of lkg aluminum can be calculated to heat about 4kg of iron from room temperature to the current 1700 ° of molten steel. C, Therefore, it is determined that the aluminum content of aluminum iron should be higher than 20%, and the aluminum content of aluminum iron is less than 60%, which is mainly considered from the density control requirements. The required density of aluminum iron is higher than 4.5g/cm ³ , and the corresponding aluminum content is 60%. It is required that the carbon content in the aluminum-iron is less than 0.01%, mainly considering the aspect of controlling carbon increase. Since the smelting steel is ultra-low carbon steel, the aluminum alloy should be controlled to increase the carbon as small as possible. In the case of 0.1%, in the case of 10kg of steel and aluminum iron, the carbon content of the molten steel is 10ppm, which is basically acceptable. Therefore, the carbon content of the aluminum iron should be less than 0.1%, which is also the production of aluminum and iron. The range of carbon content achieved. The amount of aluminum-iron added is based on the pure aluminum. The invention requires that the amount of pure aluminum added is 2~6kg/t. The addition of aluminum not only removes the dissolved oxygen in the steel, but also further reduces the pre-deoxidation process. The removed Cr ₂ O ₃ in the slag consumes about 0.5~2.4kg/t of pure aluminum, and may further react with SiO _{2 in the} slag, resulting in a silicon return of 0.1%~0.2%, and about 1.4~2.6kg of pure aluminum. /t, in addition, the target of the final aluminum content is 0.01~0.1%, about 0.1~lkg/t of pure aluminum is consumed, and the upper limit value is added and the upper limit is added to obtain the range of pure aluminum addition amount 2~ 6kg/t, the amount of aluminum and iron added is the amount of pure aluminum added divided by its aluminum content. The purpose of adding lime is to continue to ensure the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag. The invention requires the step material to be stirred under vacuum condition for 2~5min under the condition of adding, the purpose of which is to require a certain intensity of stirring on the molten steel to promote the entry of aluminum into the molten steel, and on the other hand, if the stirring strength is too large , aluminum iron will be sprayed onto the slag surface, so that aluminum can not enter the molten steel, so here, medium-strength agitation is adopted. This step requires high vacuum and strong agitation treatment time of 12~18min. It is mainly necessary to ensure sufficient time for the Α1 ₂ Ο ₃ inclusions to grow up, so that the soft agitation process under the atmospheric conditions can be fully removed. In addition, it should be pointed out that since aluminum in aluminum-iron can fully enter the molten steel, when deoxidation to a certain extent, aluminum is directly prevented from entering the slag to reduce MgO in the slag, thereby greatly restricting the magnesium-aluminum spinel. Formed, for stainless steel, magnesium aluminate spinel is a very harmful inclusion that can cause product defects. Because aluminum and aluminum are used to control the aluminum and control the silicon, the silicon content is less than 0.3% after the treatment. The aluminum content is 0.01 0.1%, and the oxygen content is less than 0.003%.

本专利对步骤（3 ) 所加铝铁的形状和密度作了要求，对于步骤（3 ) 涉及的铝铁，要求其形状为块状或球状，实密度 4.5〜6.5g/cm³，直径 3〜6cm。 This patent requires the shape and density of the aluminum iron added in the step (3). For the aluminum iron involved in the step (3), the shape is required to be a block or a sphere, and the solid density is 4.5 to 6.5 g/cm ³ , and the diameter is 3 . ~6cm.

形状为块状或球状为了方便制造和方便加入，而直径如果小于 3cm，可能会导致铝铁从料仓进入钢液熔池后，其冲击深度不够，而尺寸需小于 6cm，主要考虑尺寸太大后不方便加料。对于密度范围要求 4.5〜6.5g/cm³，主要是为了满足其加入后要 2/3部分浸入在钢液中，钢液密度 6.9〜7.2 g/cm³左右，所以要求密度要大于 4.5 g/cm³, 同时考虑铝含量不能低于 20%，则密度上限为 6.5g/cm³。 The shape is block or spherical. In order to facilitate the manufacture and convenient addition, if the diameter is less than 3cm, the aluminum iron may not be enough impact depth after entering the molten steel pool from the silo, and the size should be less than 6cm. It is not convenient to add afterwards. For the density range of 4.5~6.5g/cm ³ , it is mainly to meet the 2/3 part of the molten steel after the addition. The density of the molten steel is about 6.9~7.2 g/cm ³ , so the density is required to be greater than 4.5 g/ Cm ³ , while considering that the aluminum content cannot be less than 20%, the upper limit of the density is 6.5 g/cm ³ .

本专利对于冶炼步骤（3 ) ，要求终脱氧后，炉渣碱度即渣中 CaO与 SiO₂ 的质量比控制高于 2.8，炉渣中 CaO与 Α1₂Ο₃的质量比例高于 1。 In the smelting step (3), after the final deoxidation is required, the slag basicity, that is, the mass ratio of CaO to SiO ₂ in the slag is controlled to be higher than 2.8, and the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag is higher than 1.

终脱氧后要求炉渣碱度高于 2.8主要是从控制 SiO₂活度上考虑的，根据 CaO-SiO₂-Al₂O₃三元活度图，此碱度值条件下以纯物质为标准态 SiO₂的活度系数大约为 0.028，经过热力学计算，对于冶炼 22.6%Cr含量的超纯铁素体不锈钢为例，钢中 0.01%的铝含量和 0.3%的硅含量对应的渣中平衡 SiO₂活度为 0.009，在此碱度条件下，进一步反算出 SiO₂在渣中摩尔分数 0.32，由于碱度已经设定高于 2.8，则 SiO₂ 的百分含量必然小于 26%，此范围基本可以得出其摩尔分数一般可控制在 0.32内，由此可看出，此碱度范围可保证如上硅铝含量条件下 A1不再去还原渣中的 SiO₂。对于其他铬含量的钢种，如果铬含量小于 22.6%，由于铬是降低硅活度而提高铝活度的元素，根据冶炼热力学原理，钢中硅活度变大而铝活度降低， A1元素进一步不能去还原渣中的 SiO₂。反之， A1 元素肯能去还原渣中 SiO₂。考虑到铬含量高于 22.6%的钢种不是很多，且可以通过调节渣中 SiO₂含量的方式来阻止 A1进一步还原渣中 SiO₂，且碱度下限设定太高会导致渣量增大，所以，本发明最终确定炉渣碱度应高于 2.8，这也是对炉渣碱度值的最低要求。对于炉渣碱度，没有上限要求，主要考虑到如果铝含量要求更高，渣中 Α1₂Ο₃增大，炉渣碱度可能会上调，甚至最终的炉渣变为 SiO₂含量非常低的铝钙渣，即炉渣以 CaO-Al₂O₃为主要成分的渣，这在本发明中是允许的。本发明要求炉渣中 CaO与 Α1₂Ο₃的质量比例高于 1，主要是针对炉渣中 SiO₂ 含量较低，演变为铝钙渣的情况，要求中 CaO与 Α1₂Ο₃的质量比例高于 1，可很好地保证炉渣具有很好地吸收 Α1₂Ο₃的能力，对于铝钙渣， CaO与 Α1₂Ο₃的质量比在 1.1-1.4情况下，炉渣具有很好吸收夹杂物的能力，且具有很好的流动性。本发明对 CaO与 Α1₂Ο₃的比例上限也没有制约，主要也是针对非铝钙渣系列的情况，允许 Α1₂Ο₃在低含量范围。对于炉渣中 CaO含量的控制，已经在步骤（2 ) 和（3 ) 石灰加入量的设定中进行了控制。 After the final deoxidation, the slag basicity is higher than 2.8, which is mainly considered from the control of SiO ₂ activity. According to the ternary activity diagram of CaO-SiO ₂ -Al ₂ O ₃ , the pure substance is used as the standard SiO under the alkalinity value. The activity coefficient of ₂ is about 0.028. After thermodynamic calculation, for the ultra-pure ferritic stainless steel with smelting 22.6% Cr content, the equilibrium SiO ₂ in the slag corresponding to 0.01% aluminum content and 0.3% silicon content in steel The degree is 0.009, and under this alkalinity condition, the molar fraction of SiO ₂ in the slag is further calculated to be 0.32. Since the alkalinity has been set higher than 2.8, the percentage of SiO ₂ is inevitably less than 26%, which is basically obtained. The molar fraction can generally be controlled within 0.32, and it can be seen that this alkalinity range ensures that A1 no longer reduces SiO ₂ in the slag under the above silicon-aluminum content. For other chromium content steels, if the chromium content is less than 22.6%, since chromium is an element that reduces the silicon activity and increases the aluminum activity, according to the smelting thermodynamics principle, the silicon activity in the steel becomes larger and the aluminum activity decreases, A1 element Further, SiO ₂ in the slag cannot be reduced. On the contrary, the A1 element is able to reduce the SiO _{2 in the} slag. Considering the chromium content is not much higher than the 22.6% of the steel, and may be further reduced to prevent A1 SiO ₂ in the slag, and the lower limit is set too high will cause basicity of slag is increased by adjusting the amount of SiO ₂ content in the slag manner, Therefore, the present invention finally determines that the slag basicity should be higher than 2.8, which It is also the minimum requirement for the slag basicity value. For slag basicity, there is no upper limit requirement, mainly considering that if the aluminum content is higher, the slag Α _{1 2} Ο ₃ increases, the slag alkalinity may be increased, and even the final slag becomes a very low SiO ₂ content. That is, the slag has slag containing CaO-Al ₂ O ₃ as a main component, which is permissible in the present invention. The invention requires that the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag is higher than 1, mainly for the case that the SiO ₂ content in the slag is low and evolves into the aluminum calcium slag, and the mass ratio of CaO to Α1 ₂ Ο ₃ is required to be higher than 1, can well ensure that the slag has a good ability to absorb Α1 ₂ Ο ₃ , for the aluminum-calcium slag, the mass ratio of CaO to Α1 ₂ Ο ₃ is 1.1-1.4, the slag has a good ability to absorb inclusions. , and has good fluidity. The present invention has no restriction on the upper limit of the ratio of CaO to Α1 ₂ Ο ₃ , and mainly for the non-aluminum calcium slag series, allowing Α1 ₂ Ο _{3 to be} in a low content range. The control of the CaO content in the slag has been controlled in the setting of the amount of lime added in steps (2) and (3).

三、对于步骤（5 ) Third, for the steps (5)

1 ) 、软搅拌 1), soft mixing

喂入纯钙丝前的软搅拌让在真空条件下已经长大的夹杂物 Α1₂Ο₃夹杂物上浮进入渣相，喂入纯钙丝后的软搅拌促进喂钙后生成的低熔点铝酸钙夹杂进一步上浮进入渣相。 The soft agitation before feeding the pure calcium wire allows the inclusions that have grown up under vacuum to Α1 ₂ Ο ₃ inclusions to float into the slag phase, and the soft agitation after feeding the pure calcium wire promotes the low melting point aluminate produced after the calcium is fed. The calcium inclusions further float up into the slag phase.

2)、喂丝 2), feeding wire

A) 、喂钙丝（即钙处理工艺） A), feeding calcium wire (ie calcium treatment process)

钙处理工艺，即在常压下用喂丝机向钢液喂入纯钙丝，纯钙喂入量为 0.1〜0.3kg/t，喂完钙丝后，在常压条件下，底部吹氩对钢液进行软搅拌，软搅拌时间 5〜10min，处理结束后要求钢中钙的质量含量控制在 15〜30ppm。 Calcium treatment process, that is, feeding the pure calcium wire to the molten steel by the wire feeder under normal pressure, the pure calcium feeding amount is 0.1~0.3kg/t, after feeding the calcium wire, under the normal pressure condition, the bottom is blowing argon. The molten steel is softly stirred, and the soft stirring time is 5 to 10 min. After the treatment, the mass content of calcium in the steel is required to be controlled at 15 to 30 ppm.

由于本发明冶炼的是高铝钢，脱氧过程铝的加入量相对很大，虽然通过各种措施对生成的 Α1₂Ο₃夹杂进行了从钢液中排出，并防止二次氧化，然而，在生产实践中仍存在 Α1₂Ο₃堵塞中间包水口的风险，原因是在铝含量高的情况下，铝仍然有可能还原渣中的 MgO，形成的镁铝尖晶石夹杂很难排除，从而可能形成堵塞的起源，加上没有排除干净的 Α1₂Ο₃夹杂，从而具有水口堵塞的风险。本案已经通过各种措施将此风险降到很低，然而，为了确保高铝钢生产的高度稳定，本发明还是采用了钙处理技术，以避免水口堵塞形成的风险。钙处理主要是将 Α1₂Ο₃夹杂改变为 12CaO_7Al₂O₃的低熔点夹杂，一般认为，钢中 Α1₂Ο₃含量最大为 0.01%，将此量的 Α1₂Ο₃变为 12CaO Al₂O₃需要的钙含量为 67ppm，同时钙处理结束后钙元素自身的溶解含量一般要求为铝含量的 0.09倍至 0.15倍，如果铝含量 0.03%，则溶解钙含量约要求 30ppm，这样需要进入钢水的纯钙量则为 lOOppm即 0.01%，考虑到对于高铝钢喂钙过程钙的收得率高于 30%，最终确定纯钙喂入量为 0.1〜0.3kg/t，并最终确定钙含量控制范围 15〜30ppm，可满足本发明铝含量范围的钙处理，实现夹杂物的有效变性，若最终钙含量高于 30ppm，有侵蚀中间包水口的风险。 Since the present invention smelts high-aluminum steel, the amount of aluminum added during the deoxidation process is relatively large, although the generated Α1 ₂ Ο ₃ inclusions are discharged from the molten steel by various measures and prevent secondary oxidation, however, production practice there is still the risk of clogging of the tundish nozzle Α1 ₂ Ο _3, because of a high aluminum content in the case where aluminum is still possible to restore the slag MgO, spinel form inclusions difficult to exclude such The origin of the blockage may be formed, plus the inclusion of a clean Α1 ₂ Ο ₃ inclusion, thereby posing a risk of clogging of the nozzle. The case has been reduced to a very low level by various measures. However, in order to ensure a high degree of stability in the production of high alumina steel, the present invention also employs a calcium treatment technique to avoid the risk of clogging of the nozzle. The calcium treatment is mainly to change the Α1 ₂ Ο ₃ inclusion to the low melting point inclusion of 12CaO_7Al ₂ O ₃ . It is generally believed that the content of Α _{1 2} Ο _{3 in the} steel is 0.01% at maximum, and the amount of Α1 ₂ Ο _{3 is} changed to 12CaO Al ₂ O. _{3 The} required calcium content is 67 ppm, and the dissolved content of the calcium element itself is generally required to be 0.09 times to 0.15 times of the aluminum content after the end of the calcium treatment. If the aluminum content is 0.03%, the dissolved calcium content is required to be about 30 ppm, which requires entering the molten steel. The pure calcium content is lOOppm or 0.01%. Considering that the calcium yield of high alumina steel is higher than 30%, the pure calcium feed is determined to be 0.1~0.3kg/t, and the calcium content is finally determined. The range of 15 to 30 ppm can satisfy the calcium treatment of the aluminum content range of the present invention, and the effective denaturation of the inclusions can be achieved. If the final calcium content is higher than 30 ppm, there is a risk of eroding the intermediate water-filling port.

B ) 、喂钛丝 B), feeding titanium wire

对于要求冶炼含钛的钢种，可再向铁素体不锈钢钢液中喂入钛丝，所述钛丝中纯钛量为 l〜3kg/t，实现钛合金化。其中，纯钛量为钛丝喂入量乘以钛在钛丝中含量。 For the steel which is required to smelt titanium, the titanium wire may be further fed into the ferritic stainless steel liquid, and the amount of pure titanium in the titanium wire is l~3 kg/t, thereby realizing titanium alloying. Among them, the amount of pure titanium is the amount of titanium wire fed multiplied by the content of titanium in the titanium wire.

四、对于步骤（6 ) Fourth, for the step (6)

1 ) 、软搅拌 15~30min 1), soft stirring 15~30min

此软搅拌时间充分保证夹杂物的进一步上浮，进一步提高了钢液的纯净度。 This soft agitation time fully ensures the further floating of the inclusions, further improving the purity of the molten steel.

2 ) 、要求对钢液在保护气氛下进行连铸 2), requires continuous casting of molten steel under protective atmosphere

保护气氛下进行连铸包括了大包水口的氩气保护和中间包水口的氩气保护以及中间包上方的氩气保护，目的是防止钢液的二次氧化，对于高铝钢冶炼，这些保护也是需要的，这些为可实现的成熟连铸技术，此处不过多描述。五、对于所述中强度搅拌、高真空强搅拌和软搅拌 Continuous casting under a protective atmosphere includes argon protection of the large package and argon protection of the tundish and argon protection above the tundish to prevent secondary oxidation of the molten steel. For high aluminum steel smelting, these protections Also needed, these are achievable mature continuous casting techniques, but are not described here. 5. For the medium strength stirring, high vacuum stirring and soft stirring

其中，相关参数的设定是根据生产实践来确定的，真空条件下中强度搅拌要确保渣面不激烈翻腾，高真空强搅拌条件要保证钢液喷溅不影响生产，而软搅拌要保证渣面不被吹开，在上述条件下，根据生产摸索，最终确定了相关的底吹流量范围。 Among them, the setting of relevant parameters is determined according to the production practice. Under vacuum conditions, the medium-strength mixing should ensure that the slag surface is not drastically tumbling, and the high-vacuum strong stirring condition should ensure that the molten steel splash does not affect the production, while the soft mixing should ensure the slag. The surface is not blown off. Under the above conditions, according to the production groping, the relevant bottom blowing flow range is finally determined.

需要说明的是，本发明涉及的单位中符号 " t"表示吨钢液， " L "为升， " min" 表示分钟， " kg/t" 表示向每吨钢液中加入的公斤量， " L/(min* t) " 表示向每吨钢中、每分钟吹入的氩气量。 It should be noted that the symbol "t" in the unit of the present invention means ton of molten steel, "L" is liter, "min" means minute, and "kg/t" means the amount of kilogram added to each ton of molten steel, " L/(min* t) " indicates the amount of argon gas blown per ton of steel per minute.

实施例 Example

以下结合实施例详细说明本发明方法在生产低硅高铝铁素体不锈钢的实施方式和取得的效果，分别以生产 409、 443和 445这 3个牌号钢种的超纯铁素体不锈钢为例加以说明。 Hereinafter, the embodiment and the effect obtained by the method of the present invention for producing low-silicon high-alumina ferritic stainless steel will be described in detail with reference to the examples, respectively, taking the production of ultra-pure ferritic stainless steels of three grades of 409, 443 and 445, respectively. Explain.

实施例 1 Example 1

本实施例对精炼设备 VOD炉的要求：设备可处理钢水 120t，极限真空度小于 300Pa，底部吹氩总吹气能力高于 60Nm³/h，钢包耐火材料为镁钙砖。钢种为 409，钢液量 116000kg, 即 116t， VOD冶炼前钢液初始成分为： The requirements of the VOD furnace for refining equipment in this embodiment: The equipment can process molten steel 120t, the ultimate vacuum degree is less than 300Pa, the total blowing capacity of the bottom argon blowing is higher than 60Nm ³ /h, and the ladle refractory material is magnesia-calcium brick. The steel grade is 409, the molten steel volume is 116000kg, which is 116t. The initial composition of the molten steel before VOD smelting is:

C: 0.3%， Si: 0.25%, Cr: 11.6%， S : 0.010%， N: 0.025%, Mn: 0.56%， P: 0.015%，全 O : 0.02%， Ti: 0.01%， Al: 0.001%，其余为 Fe和微量杂质元素。 C: 0.3%, Si: 0.25%, Cr: 11.6%, S: 0.010%, N: 0.025%, Mn: 0.56%, P: 0.015%, all O: 0.02%, Ti: 0.01%, Al: 0.001% , the rest are Fe and trace impurity elements Prime.

钢液初始温度 1580°C。 The initial temperature of the molten steel is 1580 °C.

本实施例硅含量目标小于 0.26%，铝含量 0.03%左右，具体步骤如下： In this embodiment, the silicon content target is less than 0.26%, and the aluminum content is about 0.03%. The specific steps are as follows:

1) 钢液经吹氧脱碳和自由脱碳处理后，氧气消耗量为 885Nm³，自由脱碳时间 15min，处理结束后，钢液温度 1630°C，成份如下： 1) After oxygen decarburization and free decarburization, the oxygen consumption is 885Nm ³ and the free decarburization time is 15min. After the treatment, the molten steel temperature is 1630°C. The composition is as follows:

C: 0.003%， Si: 0.01%， Cr: 11.1%， S: 0.008%, N: 0.007%, Mn: 0.14%， P: 0.015%，全 O: 0.04%， Ti: 0.01%， Al: 0.001%，其余为 Fe和微量杂质元素。 C: 0.003%, Si: 0.01%, Cr: 11.1%, S: 0.008%, N: 0.007%, Mn: 0.14%, P: 0.015%, total O: 0.04%, Ti: 0.01%, Al: 0.001% The rest are Fe and trace impurity elements.

2) 预脱氧，根据最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量要求上限值为 0.27%，加入含硅 77%的硅铁 400kg (即 3.45 kg/t ，换算方法： 2) Pre-deoxidation, according to the final high-aluminum low-silicon ultra-pure ferritic stainless steel, the upper limit of silicon content is 0.27%, and the silicon-containing 77% ferrosilicon 400kg (ie 3.45 kg/t, conversion method) :

400kg÷钢液量 116t，在实施例 1范围内，除去石灰和萤石的质量外，换算方法下同）和铝块 200kg (即 1.71 kg/t) 合计 600kg (即 5.16 kg/t) 进行预脱氧，并加入石灰 1.6t，萤石 200kg进行造渣，物料加入后真空压力控制在 800Pa以下，底吹氩气搅拌强度 600L/min (即 5.17 L/(min* t)，换算方法： 600 L/min ÷ 钢液量 116t，在实施例 1范围内，换算方法下同），处理时间 8min,保证石灰初步熔化。处理结束后硅含量 0.08%, 氧含量 0.015%。 The amount of 400kg of strontium steel is 116t. In the range of Example 1, except for the mass of lime and fluorite, the equivalent of the conversion method and the 200kg of aluminum block (ie 1.71 kg/t) total 600kg (ie 5.16 kg/t). Deoxidation, adding 1.6t of lime, 200kg of fluorite for slag formation, the vacuum pressure is controlled below 800Pa after the material is added, and the stirring intensity of bottom argon gas is 600L/min (ie 5.17 L/(min* t), conversion method: 600 L /min ÷ The amount of molten steel is 116t, in the range of Example 1, the same method as the conversion method, and the treatment time is 8min to ensure the initial melting of lime. After the treatment, the silicon content was 0.08% and the oxygen content was 0.015%.

3) 终脱氧，加入含铝 40%的铝铁 650kg，铝铁直径 5cm，密度 5.4g/cm³，含碳 0.008%,，含纯铝 260kg (即 2.24 kg/t) ，并补加石灰 600kg，萤石 50kg，进行终脱氧，物料加入后调整底搅拌吹氩流量到 150L/min，中强度搅拌 3min，随后进行高强度搅拌，底吹氩气流量 800L/min (即 6.90 L/(min* t)) ，处理时间 15min。处理结束后，硅含量 0.19%，铝含量 0.054%，氧含量 7.8ppm。炉渣主要成分为： CaO 60%、 SiO₂12%、 Al₂O₃17%、 MgO 3%, 满足炉渣碱度要求和 CaO与 Α1₂Ο₃ 比值大于 1。处理结束后温度 1570°C。 3) Final deoxidation, adding 650kg of aluminum and aluminum containing 40% aluminum, 5cm diameter of aluminum iron, density 5.4g/cm ³ , containing 0.008% carbon, containing 260kg of pure aluminum (ie 2.24 kg/t), and adding 600kg of lime 50kg of fluorite, final deoxidation, adjust the bottom argon flow rate to 150L/min after the material is added, stir at medium strength for 3min, then carry out high-strength stirring, and the bottom argon flow rate is 800L/min (ie 6.90 L/(min*) t)), processing time 15min. After the treatment, the silicon content was 0.19%, the aluminum content was 0.054%, and the oxygen content was 7.8 ppm. The main components of the slag are: CaO 60%, SiO ₂ 12%, Al ₂ O ₃ 17%, MgO 3%, satisfying the slag basicity requirement and the ratio of CaO to Α1 ₂ Ο ₃ is greater than 1. The temperature after the end of the treatment was 1570 °C.

4) 破真空。 5 ) 软搅拌 10min，底吹氩气搅拌强度 200L/min (即 1.72 L/(min' t) ) 。钙处理，通过喂丝机加入纯钙丝 20kg (即 0.17kg/t) ，喂丝结束后软搅拌 lOmin, 底吹氩气搅拌强度 200L/min (即 1.72 L/(min* t) ) 。本钢种需要喂入钛丝进行钛合金化，钛丝中的纯钛量为 150kg (即 1.38kg/t) ，终点钛 0.1%。 4) Break the vacuum. 5) Soft agitation for 10 min, bottom argon gas agitation strength 200 L / min (ie 1.72 L / (min' t)). Calcium treatment, adding 20kg of pure calcium wire (ie 0.17kg/t) through the wire feeder, soft agitation lOmin after the end of the feeding, and the bottom argon stirring intensity is 200L/min (ie 1.72 L/(min* t)). The steel grade needs to be fed with titanium wire for titanium alloying. The amount of pure titanium in the titanium wire is 150 kg (ie 1.38 kg/t), and the end point titanium is 0.1%.

6 )继续软搅拌 20min，底吹氩气搅拌强度 180L/min (即 1.55L/(min* t) ) 。保护气氛中连铸，大包水口、中间包水口均有吹氩保护。 6) Continue soft agitation for 20 min, and the bottom argon gas agitation intensity is 180 L/min (ie 1.55 L/(min* t)). The continuous casting in the protective atmosphere, the large package nozzle and the tundish nozzle are protected by argon blowing.

浇铸过程中中间包水口开口度非常稳定，不发生剧烈的波动，且总的波动范围在 3%以内，表明没有发生水口结塞，也没有发生水口侵蚀。 During the casting process, the opening angle of the tundish is very stable, no sharp fluctuations occur, and the total fluctuation range is within 3%, indicating that no nozzle clogging occurs and no nozzle erosion occurs.

最终钢液被浇铸成坯，成分如下： The final molten steel is cast into a billet with the following composition:

C : 0.006%， Si : 0.20%, Cr: 11.7%, S : 0.001%， N : 0.008%, Mn: C : 0.006%, Si : 0.20%, Cr: 11.7%, S : 0.001%, N : 0.008%, Mn:

0.23%, P : 0.015%，全 O : 0.0020%， Ti: 0.09%， Al: 0.044%，其余为 Fe和微量杂质元素。 0.23%, P: 0.015%, all O: 0.0020%, Ti: 0.09%, Al: 0.044%, and the balance is Fe and trace impurity elements.

其中硅含量在破真空后略有上升，可能是渣中 SiO₂ 少量被铝还原的结果；而铝含量略有下降，原因是随着温度的降低和时间的推移以及可能的二次氧化，促使了铝与氧的接触，导致其成分略微下降；脱氧过程由于加入的铝铁含有一定量的碳,导致碳含量相对处理前有一定程度上升,但仍在超纯的范围内。 The silicon content increases slightly after vacuum breaking, which may be the result of a small reduction of SiO ₂ in the slag by aluminum; while the aluminum content decreases slightly due to the decrease in temperature and the passage of time and possible secondary oxidation. The contact between aluminum and oxygen causes a slight decrease in its composition. The deoxidation process has a certain amount of carbon due to the addition of a certain amount of carbon, which is still in the ultrapure range.

铸坯中镁铝尖晶石夹杂物数量相对常规流程大大减少，夹杂物主要是尺寸在 5 μ m以下的 TiN或 Ti(CN)夹杂和 10 μ m以下的球状的塑性 CaO-Al₂O₃-SiO₂夹杂（部分含少量 MgO ) ，对钢的性能尤其表面性能无有害影响。 The amount of Mg-Al spinel inclusions in the slab is greatly reduced compared to the conventional process. The inclusions are mainly TiN or Ti(CN) inclusions below 5 μm and spherical plastic CaO-Al ₂ O ₃ below 10 μm. - SiO ₂ inclusions (partially containing a small amount of MgO) has no detrimental effect on the properties of the steel, especially the surface properties.

实施例 2 Example 2

本实施例对精炼设备 VOD的要求：设备可处理钢水 120t，极限真空度小于 300Pa，底部吹氩总吹气能力高于 60Nm³/h，钢包耐火材料为镁钙砖。钢种为 443，钢液量 108400kg, 即 108.4t， VOD冶炼前钢液初始成分为： The requirements of the refining equipment VOD in this embodiment: The equipment can process molten steel 120t, the ultimate vacuum degree is less than 300Pa, the total blowing capacity of the bottom argon blowing is higher than 60Nm ³ /h, and the ladle refractory material is magnesia-calcium brick. Steel grade For 443, the amount of molten steel is 108400kg, which is 108.4t. The initial composition of the molten steel before VOD smelting is:

C : 0.36%， Si: 0.018%, Cr: 20.8%, S : 0.005%, N: 0.015%， Mn: 0.3%， P : 0.010%，全 O : 0.02%， Ti : 0.01%， A 0.001%，其余为 Fe和微量杂质元素。 C: 0.36%, Si: 0.018%, Cr: 20.8%, S: 0.005%, N: 0.015%, Mn: 0.3%, P: 0.010%, all O: 0.02%, Ti: 0.01%, A 0.001%, The rest are Fe and trace impurity elements.

钢液初始温度 1600°C。 The initial temperature of the molten steel is 1600 °C.

本实施例硅含量目标小于 0.2%，铝含量 0.02%左右，具体步骤如下： In this embodiment, the silicon content target is less than 0.2%, and the aluminum content is about 0.02%. The specific steps are as follows:

1 ) 钢液经吹氧脱碳和自由脱碳处理后，氧气消耗量为 1266Nm³，自由脱碳时间 20min，处理结束后，钢液温度 1670°C，成份如下： 1) After oxygen decarburization and free decarburization, the oxygen consumption is 1266Nm ³ and the free decarburization time is 20min. After the treatment, the molten steel temperature is 1670 °C. The composition is as follows:

C : 0.005%， Si : 0.01%， Cr: 19.7%, S : 0.004%， N : 0.004%， Mn: 0.14%， P : 0.015%，全 O : 0.05%， Ti: 0.01%， Al: 0.001%，其余为 Fe和微量杂质元素。 C: 0.005%, Si: 0.01%, Cr: 19.7%, S: 0.004%, N: 0.004%, Mn: 0.14%, P: 0.015%, Total O: 0.05%, Ti: 0.01%, Al: 0.001% The rest are Fe and trace impurity elements.

2 ) 预脱氧，根据最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量要求上限值为 0.2%，此要求条件下全部加入铝块，而不加硅铁，避免增硅，加入铝块 780kg (即 7.20kg/t ，换算方法： 780kg ÷钢液量 108.4t，在实施例 2 范围内，除去石灰和萤石的质量外，换算方法下同）进行预脱氧,并加入石灰 1.6t，萤石 100kg进行造渣，物料加入后真空压力控制在 800Pa以下，底吹氩气搅拌强度 700L/min (即 6.46L/(min* t)，换算方法： 700L/min÷钢液量 108. 4t，在实施例 2范围内，换算方法下同），处理时间 6min,保证石灰初步熔化。处理结束后硅含量 0.04%, 氧含量 0.02%。 2) Pre-deoxidation, according to the final high-aluminum low-silicon ultra-pure ferritic stainless steel, the upper limit of silicon content is 0.2%. Under this requirement, all aluminum blocks are added without adding ferrosilicon to avoid silicon. Add 780kg of aluminum block (ie 7.20kg/t, conversion method: 780kg ÷Steel liquid volume 108.4t, in the range of Example 2, remove the quality of lime and fluorite, the same method as the conversion method), pre-deoxidize, and join Lime 1.6t, fluorite 100kg for slag formation, the vacuum pressure is controlled below 800Pa after the material is added, and the bottom argon gas agitation strength is 700L/min (ie 6.46L/(min* t), conversion method: 700L/min strontium steel The amount of 108. 4t, in the range of Example 2, the same method as the conversion method, and the treatment time of 6 minutes, ensure the initial melting of the lime. After the treatment, the silicon content was 0.04% and the oxygen content was 0.02%.

3) 终脱氧，加入含铝 40%的铝铁 500kg (即 4.61kg/t) ，铝铁直径 5cm，密度 5.4g/cm³，含碳 0.01%，含纯铝 200kg (即 1.85kg/t) ，并补加石灰 400kg，萤石 50kg，进行终脱氧，物料加入后调整底搅拌吹氩流量到 200L/min (即 1.85L/(min - t) ) ，中强度搅拌 4min，随后进行高强度搅拌，底吹氩气流量 800L/min (即 7.38 L/(min* t) ) ，处理时间 18min。处理结束后，硅含量 0.20%，铝含量 0.018%，氧含量 10ppm。炉渣主要成分为： CaO 55% 、 SiO₂ 2%、 Α1₂Ο₃ 37%、 MgO 5%，满足炉渣碱度要求和 CaO与 Α1₂Ο₃ 比值大于 1。处理结束后温度 1605 °C。 3) Final deoxidation, adding 500kg of aluminum-containing aluminum 500kg (ie 4.61kg/t), aluminum iron diameter 5cm, density 5.4g/cm ³ , carbon content 0.01%, containing pure aluminum 200kg (ie 1.85kg/t) And add 400kg of lime, 50kg of fluorite, and finally deoxidize. After the material is added, adjust the bottom argon flow to 200L/min (ie 1.85L/(min - t)), stir at medium strength for 4min, then carry out high-strength stirring. The bottom argon flow rate is 800L/min (ie 7.38 L/(min* t)) and the treatment time is 18 min. After the treatment, the silicon content is 0.20%. The aluminum content is 0.018% and the oxygen content is 10 ppm. The main components of the slag are: CaO 55%, SiO ₂ 2%, Α1 ₂ Ο ₃ 37%, MgO 5%, satisfying the slag basicity requirement and the ratio of CaO to Α1 ₂ Ο ₃ is greater than 1. The temperature after the treatment was 1605 °C.

4 ) 破真空。 4) Break the vacuum.

5 ) 软搅拌 9min，底吹氩气搅拌强度 200L/min (即 1.85L/(min* t) ) 。钙处理，通过喂丝机加入纯钙丝 12.8kg (即 0.12kg/t)，喂丝结束后软搅拌 lOmin, 底吹氩气搅拌强度 200L/min (即 1.85 L/(min* t) ) 。本钢种需要喂入钛丝进行钛合金化，所述钛丝中纯钛量为 300kg (即 2.77 kg/t) ，终点钛 0.2%。 5) Soft agitation for 9 min, bottom argon agitation intensity 200 L / min (ie 1.85 L / (min * t)). Calcium treatment, adding 12.8kg (ie 0.12kg/t) of pure calcium wire through the feeding machine, soft stirring lOmin after the feeding, and stirring strength of 200L/min (ie 1.85 L/(min* t)). The steel grade needs to be fed with titanium wire for titanium alloying, wherein the amount of pure titanium in the titanium wire is 300 kg (i.e., 2.77 kg/t), and the end point titanium is 0.2%.

6 )继续软搅拌 25min，底吹氩气搅拌强度 160L/min (即 1.48 L/(min- t) ) 。保护气氛中连铸，大包水口、中间包水口均有吹氩保护。 6) Continue soft agitation for 25 min, and the bottom argon gas agitation intensity is 160 L/min (ie 1.48 L/(min-t)). The continuous casting in the protective atmosphere, the large package nozzle and the tundish nozzle are protected by argon blowing.

C : 0.008%, Si : 0.20%, Cr: 20.8%, S : 0.001%， N : 0.006%， Mn_: 0.21%, P : 0.015%，全 O : 0.0018%， Ti: 0.15%， Al: 0.019%，其余为 Fe和微量杂质元素。 C : 0.008%, Si : 0.20%, Cr: 20.8%, S : 0.001%, N : 0.006%, Mn _: 0.21%, P : 0.015%, Total O : 0.0018%, Ti: 0.15%, Al: 0.019% The rest are Fe and trace impurity elements.

其中铝含量略有上升，这是由于喂钛进一步降低钢液氧势的原因；而硅含量保持不变，原因是渣中 SiO₂含量极低，避免了铝或钛进一步还原渣中硅脱氧过程；由于加入的铝铁含有一定量的碳,导致碳含量相对处理前有一定程度上升，但仍在超纯的范围内。 The aluminum content is slightly increased, which is because the feeding of titanium further reduces the oxygen potential of the molten steel; while the silicon content remains unchanged, because the SiO ₂ content in the slag is extremely low, avoiding the deoxidation process of silicon in the further reduction of aluminum or titanium. Since the added aluminum iron contains a certain amount of carbon, the carbon content is increased to some extent before the treatment, but it is still in the ultrapure range.

铸坯中镁铝尖晶石夹杂物数量相对常规流程大大减少，夹杂物主要是尺寸在 5 μ m以下的 TiN或 Ti(CN)夹杂和 10 μ m以下的球状的塑性 CaO-Al₂O₃-SiO₂夹杂（部分含少量 MgO ) ，对钢的性能尤其表面性能无有害影响。实施例 3 The amount of Mg-Al spinel inclusions in the slab is greatly reduced compared to the conventional process. The inclusions are mainly TiN or Ti(CN) inclusions below 5 μm and spherical plastic CaO-Al ₂ O ₃ below 10 μm. - SiO ₂ inclusions (partially containing a small amount of MgO) has no detrimental effect on the properties of the steel, especially the surface properties. Example 3

本实施例对精炼设备 VOD的要求：设备可处理钢水 120t，极限真空度小于 300Pa，底部吹氩总吹气能力高于 60Nm3/h，钢包耐火材料为镁钙砖。钢种为 444，钢水量 110000kg, 即 110t， VOD冶炼前钢液初始成分为： The requirements of the VOD of the refining equipment in this embodiment: The equipment can process molten steel 120t, the ultimate vacuum is less than 300Pa, the total blowing capacity of the bottom argon blowing is higher than 60Nm3/h, and the ladle refractory material is magnesia-calcium brick. The steel grade is 444, the molten steel volume is 110000kg, which is 110t. The initial composition of the molten steel before VOD smelting is:

C : 0.40 %， Si: 0.06%， Cr: 18.8%, S : 0.005%, N: 0.012%, Mn: C : 0.40 %, Si: 0.06%, Cr: 18.8%, S : 0.005%, N: 0.012%, Mn:

0.3%， P : 0.010%，全 O : 0.02%， Ti : 0.01%， A 0.001%，其余为 Fe和微量杂质元素。 0.3%, P: 0.010%, all O: 0.02%, Ti: 0.01%, A 0.001%, and the balance is Fe and a small impurity element.

钢液初始温度 1620°C。 The initial temperature of the molten steel is 1620 °C.

本实施例硅含量目标小于 0.3%，铝含量 0.04%左右，具体步骤如下： 1 ) 钢液经吹氧脱碳和自由脱碳处理后，氧气消耗量为 1440Nm³，自由脱碳时间 20min，处理结束后，钢液温度 1700°C，成份如下： In this embodiment, the silicon content target is less than 0.3%, and the aluminum content is about 0.04%. The specific steps are as follows: 1) After the molten steel is deoxidized by deoxygenation and free decarburization, the oxygen consumption is 1440 Nm ³ and the free decarburization time is 20 min. After the end, the molten steel temperature is 1700 ° C, the composition is as follows:

C : 0.006%， Si : 0.20%, Cr: 17.4%, S : 0.005%， N : 0.005%， Mn: 0.14%， P : 0.015%，全 O : 0.05%， Ti: 0.01%， Al: 0.001%，其余为 Fe和微量杂质元素。 C: 0.006%, Si: 0.20%, Cr: 17.4%, S: 0.005%, N: 0.005%, Mn: 0.14%, P: 0.015%, Total O: 0.05%, Ti: 0.01%, Al: 0.001% The rest are Fe and trace impurity elements.

2 ) 预脱氧，根据最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量要求上限值为 0.3%，此要求条件下全加入硅铁，而不加入铝块，加入含 77% 硅的硅铁 900kg (即 8.12kg/t，换算方法： 900kg ÷钢液量 110t ，在实施例 3范围内，除去石灰和萤石的质量外，换算方法下同），不加入铝块预脱氧,并加入石灰 3.6t，萤石 200kg进行造渣，物料加入后真空压力控制在 400Pa以下，底吹氩气搅拌强度 800L/min (即 7.27L/(min* t)，换算方法： 800L/min÷钢液量 110t，在实施例 3范围内，换算方法下同），处理时间 lOmin,保证石灰初步熔化。处理结束后硅含量 0.1%, 氧含量 0.013%。 2) Pre-deoxidation, according to the final high-aluminum low-silicon ultra-pure ferritic stainless steel, the upper limit of silicon content is 0.3%. Under this requirement, all ferrosilicon is added without adding aluminum block. % Silicon ferrosilicon 900kg (ie 8.12kg / t, conversion method: 900kg ÷ molten steel volume 110t, in the scope of Example 3, except for the quality of lime and fluorite, the same as the conversion method), do not add aluminum block pre Deoxidation, adding 3.6t of lime, 200kg of fluorite for slagging, the vacuum pressure is controlled below 400Pa after the material is added, and the stirring intensity of argon gas is 800L/min (ie 7.27L/(min* t), conversion method: 800L/ The amount of molten steel of min÷ is 110t, in the range of Example 3, the same as the conversion method, and the treatment time is lOmin to ensure the initial melting of lime. After the treatment, the silicon content was 0.1% and the oxygen content was 0.013%.

3) 终脱氧，加入含铝 47%的铝铁 750kg (即 6.82kg/t) ，铝铁直径 5cm，密度 5.1g/cm³，含碳 0.007%,含纯铝 350kg (即 3.18 kg/t) ，并补加石灰 700kg，萤石 200kg,进行终脱氧，物料加入后调整底搅拌吹氩流量到 200L/min (即 1.82 L/(min- t) )，中强度搅拌 5min，随后进行高强度搅拌，底吹氩气流量 750L/min (即 6.82 L/(min* t) ) ，处理时间 18min。处理结束后，硅含量 0.27%，铝含量 0.035%，氧含量 10ppm。炉渣主要成分为： CaO 65% 、 SiO₂18%、 Α1₂Ο₃ 10%、 MgO5%，满足炉渣碱度要求和 CaO与 Al₂O₃比值大于 1。处理结束后温度 1642 °C。 3) Final deoxidation, add 750kg (ie 6.82kg/t) of aluminum and iron containing 47% aluminum, 5cm diameter of aluminum iron, density 5.1g/cm ³ , 0.007% carbon, 350kg pure aluminum (ie 3.18 kg/t) And add 700kg of lime, Fluorite 200kg, final deoxidation, after the material is added, adjust the bottom stirring argon flow rate to 200L / min (ie 1.82 L / (min - t)), medium strength stirring for 5min, followed by high-intensity mixing, bottom argon flow 750L /min (ie 6.82 L/(min* t) ), processing time 18 min. After the treatment, the silicon content was 0.27%, the aluminum content was 0.035%, and the oxygen content was 10 ppm. The main components of the slag are: CaO 65%, SiO ₂ 18%, Α1 ₂ Ο ₃ 10%, MgO5%, satisfying the slag basicity requirement and the ratio of CaO to Al ₂ O ₃ is greater than 1. The temperature after the end of the treatment was 1642 °C.

4 ) 破真空。 4) Break the vacuum.

5 ) 软搅拌 10min，底吹氩气搅拌强度 200L/min (即 1.82L/(min* t) ) 。钙处理，通过喂丝机加入纯钙丝 25kg (即 0.23kg/t)，喂丝结束后软搅拌 lOmin, 底吹氩气搅拌强度 180L/min (即 1.64 L/(min* t) ) 。本钢种无需钛合金化，故无需喂钛丝。 5) Soft agitation for 10 min, bottom argon gas agitation intensity 200 L / min (ie 1.82 L / (min * t)). Calcium treatment, adding 25kg of pure calcium wire (ie 0.23kg/t) through the wire feeder, soft agitation lOmin after the feeding, and the bottom argon stirring intensity is 180L/min (ie 1.64 L/(min* t)). This steel grade does not require titanium alloying, so there is no need to feed titanium wire.

6 )继续软搅拌 15min，底吹氩气搅拌强度 180L/min (即 1.64 L/(min* t) ) 。保护气氛中连铸，大包水口、中间包水口均有吹氩保护。 6) Continue soft agitation for 15 min, and the bottom argon gas agitation intensity is 180 L/min (ie 1.64 L/(min* t)). The continuous casting in the protective atmosphere, the large package nozzle and the tundish nozzle are protected by argon blowing.

浇铸过程中中间包水口开口度非常稳定，不发生剧烈的波动，且总的波动范围在 5%以内，表明没有发生水口结塞，也没有发生水口侵蚀。 During the casting process, the opening angle of the tundish is very stable, no sharp fluctuations occur, and the total fluctuation range is within 5%, indicating that no nozzle clogging occurs and no nozzle erosion occurs.

C: 0.01%， Si: 0.29%, Cr: 18.6%, S : 0.001%, N: 0.007%, Mn: 0.21%, P: 0.015%，全 O : 0.0017%， Ti: <0.01%， Al: 0.030%, 其余为 Fe和微量杂质元素。 C: 0.01%, Si: 0.29%, Cr: 18.6%, S: 0.001%, N: 0.007%, Mn: 0.21%, P: 0.015%, total O: 0.0017%, Ti: <0.01%, Al: 0.030 %, the rest are Fe and trace impurity elements.

而铝含量略有下降，而硅含量保持略有上升，原因是渣中 SiO₂含量较高，引起了铝进一步还原渣中硅，脱氧过程由于加入的铝铁含有一定量的碳，导致碳含量相对处理前有一定程度上升,但仍在超纯的范围内。 The aluminum content decreased slightly, while the silicon content remained slightly increased, because the SiO ₂ content in the slag was higher, causing the silicon to further reduce the silicon in the slag. The deoxidation process caused the carbon content due to the added aluminum iron. There is a certain increase before the treatment, but it is still in the ultra-pure range.

铸坯中镁铝尖晶石夹杂物数量相对常规流程大大减少，夹杂物主要是尺寸在 ΙΟ μ ηι以下的球状的塑性 CaO-Al₂O₃-SiO₂夹杂（部分含少量 MgO ) ，对钢的性能尤其表面性能无有害影响。 The amount of Mg-Al spinel inclusions in the slab is greatly reduced compared with the conventional process. The inclusions are mainly spherical plastic CaO-Al ₂ O ₃ -SiO ₂ inclusions (partially containing a small amount of MgO) having a size below ΙΟ μ ηι. The properties of the steel, especially the surface properties, have no detrimental effect.

本发明所提供的一种高铝低硅超纯铁素体不锈钢的冶炼方法，可冶炼硅含量小于 0.3%，铝含量 0.01〜0. 1%的低硅高铝超纯净铁素体不锈钢，钢坯全氧含量小于 30ppm，提高了产品的酸洗性能，本方法还可有效抑制有害夹杂物镁铝尖晶石的形成，有效去除 Α1₂Ο₃夹杂物，并在含钛钢中抑制了钛的氧化，避免了连铸过程的中间包水口堵塞。 The invention provides a method for smelting a high-alumina low-silicon ultra-pure ferritic stainless steel, which can smelt a silicon content of less than 0.3%, an aluminum content of 0.01 to 0.1%, a low-silicon high-alloy ultra-pure ferritic stainless steel, a billet The total oxygen content is less than 30ppm, which improves the pickling performance of the product. The method can also effectively inhibit the formation of the harmful inclusion magnesium aluminate spinel, effectively remove the Α1 ₂ Ο ₃ inclusions, and inhibit the titanium in the titanium-containing steel. Oxidation avoids blockage of the tundish in the continuous casting process.

Claims

1. 一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，包括如下步骤： A method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel, comprising the steps of:

( 4 ) 、破真空； (4), breaking the vacuum;

( 6 ) 、继续软搅拌 15〜30min，之后将铁素体不锈钢钢液在保护气氛中进行连铸，最终得到高铝低硅超纯铁素体不锈钢。 (6), continue soft agitation for 15~30min, then cast the ferritic stainless steel in a protective atmosphere, and finally obtain high-alumina low-silicon ultra-pure ferritic stainless steel.

2. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，步骤（2 ) 中，所述硅铁和 /或铝块总加入量为 4〜9kg/t，所述硅铁中硅的质量百分含量为 70〜80%，所述石灰加入质量取值为如下两个范围中的较大值：硅铁加入质量的 4〜6倍或铝块加入质量的 2〜3倍；所述萤石加入质量为石灰加入质量的 0.05〜0.3倍，经步骤（2 ) 处理后，所述铁素体不锈钢钢液中硅的质量含量小于 0. 1%、大于 0，要求氧的质量含量大于 0.01%。 2 . The method for smelting high alumina low silicon ultra pure ferritic stainless steel according to claim 1 , wherein in step ( 2 ), the total amount of the ferrosilicon and/or aluminum block is 4~. 9kg/t, the mass percentage of silicon in the ferrosilicon is 70~80%, and the mass of the lime added is the larger of the following two ranges: the ferrosilicon is added 4~6 times of the mass or aluminum The mass content of silicon in the ferritic stainless steel liquid is less than 0.1, the mass of the ferritic stainless steel liquid is less than 0.1. %, greater than 0, requires a mass content of oxygen greater than 0.01%.

3. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，步骤（3 ) 中，所述铝铁中纯铝的加入量为 2〜6kg/t，所述石灰的加入量为铝铁中纯铝加入量的 2〜3倍，萤石加入量为石灰加入质量的 0.05〜0.3倍，经步骤（3 ) 处理后，所述铁素体不锈钢钢液中硅的质量含量小于 0.3%、大于 0，铝的质量含量为 0.01〜0. 1%，氧的质量含量小于 0.003%。 3. The method for smelting high alumina low silicon ultra-pure ferritic stainless steel according to claim 1, wherein in step (3), the amount of pure aluminum in the aluminum iron is 2 to 6 kg/ t, the lime is added in an amount of 2 to 3 times the amount of pure aluminum added in the aluminum iron, and the fluorite is added in an amount of 0.05 to 0.3 times the mass of the lime added. After the step (3), the ferritic stainless steel is processed. The mass content of silicon in the molten steel is less than 0.3%, greater than 0, and the mass content of aluminum is 0.01 to 0.1%, and the mass content of oxygen is less than 0.003%.

4. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，在步骤（5 ) 中，所述喂钙丝为向铁素体不锈钢钢液中喂入纯钙丝，所述纯钙丝喂入量为 0.1〜0.3kg/t，经步骤（5 ) 处理后，所述铁素体不锈钢钢液中钙的质量含量为 15〜30ppm。 4. The smelting method of a high-alumina low-silicon ultra-pure ferritic stainless steel according to claim 1, wherein in the step (5), the calcium-feeding wire is in a ferritic stainless steel molten steel. The pure calcium wire is fed, and the pure calcium wire is fed in an amount of 0.1 to 0.3 kg/t. After the step (5), the calcium content in the ferritic stainless steel liquid is 15 to 30 ppm.

5. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，在步骤（5 ) 中，喂完钙丝并软搅拌后，向铁素体不锈钢钢液中喂入钛丝，所述钛丝中的纯钛量为 l~3kg/t。 5. The smelting method of a high alumina low silicon ultra-pure ferritic stainless steel according to claim 1, wherein in the step (5), after the calcium wire is fed and softly stirred, the ferritic stainless steel is applied. Titanium wire is fed into the molten steel, and the amount of pure titanium in the titanium wire is 1-3 kg/t.

6. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，在最终所制得的高铝低硅超纯铁素体不锈钢中，硅质量百分含量小于 0.3%，铝质量百分含量为 0.01 0.1%。 6. The smelting method of a high-alumina low-silicon ultra-pure ferritic stainless steel according to claim 1, wherein in the finally obtained high-aluminum low-silicon ultra-pure ferritic stainless steel, silicon quality is 100 The content of the fraction is less than 0.3%, and the mass percentage of aluminum is 0.01 0.1%.

7. 根据权利要求 1或 2所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，步骤（2 ) 中， The smelting method of a high-alumina low-silicon ultra-pure ferritic stainless steel according to claim 1 or 2, wherein in step (2),

当要求最终制得的高铝低硅超纯铁素体不锈钢中硅质量含量的上限值为 0.3%时，全部加入硅铁； When the upper limit of the mass content of silicon in the high-alumina low-silicon ultra-pure ferritic stainless steel finally required is 0.3%, all of the ferrosilicon is added;

8. 根据权利要求 1或 3所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于，步骤（3 ) 中，所述铝铁形状为块状或球状，密度为 4.5~6.5g/cm³，直径 3〜6cm; 经步骤（3 ) 处理后，炉渣中 CaO与 SiO₂的质量比高于 2.8，炉渣中 CaO与 Α1₂Ο₃的质量比高于 1。 The method for smelting high-aluminum low-silicon ultra-pure ferritic stainless steel according to claim 1 or 3, wherein in the step (3), the aluminum-iron is in the form of a block or a sphere, and the density is 4.5~6.5g/cm ³ , diameter ³ ~6cm; After the step (3), the mass ratio of CaO to SiO ₂ in the slag is higher than 2.8, and the mass ratio of CaO to Α1 ₂ Ο ₃ in the slag is higher than 1.

9. 根据权利要求 1所述的一种高铝低硅超纯铁素体不锈钢的冶炼方法，其特征在于， 9. The method for smelting high alumina low silicon ultra-pure ferritic stainless steel according to claim 1, wherein

所述软搅拌的条件为：在常压条件下， VOD 炉底部吹氩流量控制 l~5L/(min* t)之间。 The conditions of the soft agitation are: Under normal pressure conditions, the flow rate of argon blowing at the bottom of the VOD furnace is between l~5L/(min*t).