180t RH工艺技术优化与改进

针对180 t RH精炼工艺存在的真空度低、超低碳钢处理时间长、钢中氧含量高及脱硫效率低等问题,研究并优化了RH真空脱气、脱碳升温、脱氧、脱硫等工艺,使RH工作真空度提高到100 Pa以下,超低碳钢处理时间缩短至平均36.5 min,超低碳钢钢中氧的质量分数最低为13×10-6。优化工艺降低了钢中[H]、[N]、[C]、[O]、[S]等元素的含量,提高了钢水洁净度,缩短了RH精炼时间,提高了RH精炼生产率。     

RH-MFB生产超低碳钢实践

采用工业试验,研究RH-MFB生产超低碳钢过程中的脱碳规律和RH脱碳后的增碳规律。试验结果:(1)采用真空室快速压降速率、较长的极限真空保持时间,可使RH具有强大的脱碳能力,RH脱碳结束后钢水w(C)可达到8×10-6的水平。(2)钢包、钢包覆盖剂、中包覆盖剂和连铸保护渣等采用低碳材料,可以有效防止RH脱碳后的钢水增碳,可以将增碳量控制在4×10-6的水平。     

RH-KTB预熔渣深脱硫实践

在宝钢炼钢厂300 t RH-KTB上进行了超低碳超低硫钢的预熔渣深脱硫试验。试验共12炉,预熔渣加入量为4 kg/t。试验结果表明,在RH平均初始w(S)为42.1×10-6条件下,处理终点平均w(S)达到30×10-6,最低w(S)达到22×10-6,最高脱硫率达到36.6%,平均脱硫率达到28.6%,取得了较好的深脱硫效果。采用预熔渣处理过程钢中w(TO)及w(N)均有所降低。试验炉次钢中最低w(TO)为12×10-6,平均w(TO)为13.3×10-6,最低w(N)为11×10-6,平均w(N)为13.8×10-6。RH终点钢中的夹杂物主要是Al2O3,95.1%的夹杂物小于5μm。     

RH复合脱硫剂的开发及在太钢精炼工序中的试验

提供了一种适合超低碳钢用RH真空处理脱硫剂,解决了现有技术中RH真空处理脱硫时存在脱硫率低,对耐火材料侵蚀较大,熔化慢,对钢液有增碳风险的问题。该脱硫剂能提高脱硫效率,稳定脱硫率大于30%,提高钢水纯净度,且能提高耐材使用寿命,与使用配加萤石的方式相比,可提高耐火材料寿命,降低综合生产成本。     

罩型环流机械真空精炼装置脱碳实践

敬业钢铁有限公司新建一台罩型环流机械真空精炼设备,生产无取向硅钢和工业纯铁等超低碳品种钢,控制环节上从转炉碳温协调出钢、制定罩型环流机械真空精炼装置的脱碳工艺、控制原材料碳含量等方面入手,冶炼出w(C)≤20×10~(-6)的工业纯铁等超低碳钢。结果表明:超低碳钢生产过程中,转炉出钢碳质量分数要控制在0.025%～0.040%,采用真空吹氧的条件下转炉出钢碳质量分数可以放宽到0.060%以下,且转炉终点要注意碳温协调出钢,出钢过程严禁加含铝或硅的脱氧合金;真空脱碳需要分段控制脱碳期真空度和钢包底吹驱动气体流量。为防止钢液增碳,应采用碳含量低的合金和耐材。     

IF钢的RH-KTB工艺优化

介绍了RH-KTB深脱碳热力学及动力学原理,并结合梅山150t RH生产IF钢实践,重点从改善动力学条件出发,优化超低碳钢RH-KTB处理工艺,通过采取一系列措施如将真空度达到15kPa作为最佳KTB时机,优化KTB吹氧制度,提高RH真空度,提高循环流量,增加浸渍管插入深度等,使RH冶炼IF钢终点碳的质量分数由18×10-6稳定控制在15×10-6以下,对超低碳钢终点碳含量控制已达到国内先进水平。     

转炉出钢过程中渣洗脱硫的试验研究

通过试验研究了转炉渣洗脱硫的效果和影响因素,以及该工艺对精炼环节和钢水成分的影响。结果表明：不同预熔渣的渣洗脱硫率差别较大,其脱硫率决定于其物化性能;渣洗脱硫可缩短LF精炼时间;采用渣洗工艺后可减轻低碳钢在精炼过程中的增碳和增硅现象。     

CaO-Al_2O_3-MgO-SiO_2-CaF_2渣系RH脱硫动力学实验研究

采用动力学分析和真空感应炉实验的方法对RH深脱硫工艺进行了研究。结果表明:RH深脱硫主要受钢液和炉渣的初始硫含量、表观传质系数和钢-渣质量比的影响;当钢中的初始硫含量约为0.01%时,终点[S]含量可以降至0.003%以下,平均脱硫率为81.2%;模型预测值与实际检测值误差在±2×10-6以内的比例为82.9%,模型预测值与实验值较为接近;实验室RH脱硫的限制性环节为硫在钢水中的传质,渣量控制在5%~8%时,增加钢-渣界面的反应面积与硫的传质速度可以提高脱硫效率,脱硫效果良好。     

RH精炼脱硫低碳石灰生产工艺的开发及应用

从石灰焙烧原理、RH精炼脱硫工艺指标要求、石灰石原矿现状三方面综合分析设计开发出适合太钢炼钢二厂RH真空深度脱硫用低碳石灰生产工艺。该工艺选用传统回转窑对石灰石进行煅烧,成本低,产能大,工艺指标稳定;采用该工艺煅烧的低碳石灰在太钢炼钢二厂使用效果良好,平均终点硫含量(质量分数)为30×10-6,试验炉次平均脱硫率达到37.73%,平均脱硫(硫含量)量为20×10-6,加入后几乎不增碳。该工艺在RH精炼中被广泛应用,该工艺煅烧的低碳石灰石在其他精炼炉如AOD上作为造渣熔剂使用。     

超低碳钢方坯连铸钢水关键精炼工艺研究

介绍了小方坯连铸超低碳钢水的转炉冶炼、LF精炼和RH真空处理的生产工艺,针对钢水可浇性差和钢中Si含量偏高问题进行工艺技术优化。试验研究表明,降低LF脱硫任务,采用少渣精炼,造渣料石灰加入量控制在6. 5~7. 5 kg/t有利于钢包顶渣改质和控制钢中[Si]含量;RH根据经验公式确定吹氧量,既能满足强制脱碳的需要又可防止钢水过氧化,破真空后用高铝渣对顶渣进行改质,控制渣中TFe质量分数小于1. 0%,并对钢水Ca处理,有效提高了钢水的可浇性,顺利实现超低碳钢小方坯连铸。     

CaO-Al2O3-CaF2-MgO-SiO2五元预熔渣系钢水深脱硫实验研究

文中采用二次正交回归实验设计方法对CaO-Al2O3-CaF2-MgO-SiO2五元预熔渣系钢水深脱硫效果进行了实验研究，分析了实验条件下预熔渣光学碱度，渣中Al2O3含量，CaF2含量与钢水脱硫率的关系，并获得了该预熔渣系的最佳组成。     

铝灰在管线钢脱硫中的作用

通过实验室脱硫实验,研究了不同铝灰代替精炼渣中的三氧化二铝构成的铝灰脱硫剂的脱硫效果。结果表明,铝灰脱硫效果令人满意,管线钢中w(S)可从0.005〖KG-*9〗0%降至0.002〖KG-*9〗0%左右。比较几种铝灰脱硫剂,按照脱硫率从大到小的顺序依次为：无氟电解铝灰渣系、实验室自配渣、预熔电解铝灰渣系、电解铝灰渣系、预熔熔铸铝灰渣系、熔铸铝灰渣系,脱硫率分别达63.3%、57.4%、55.7%、53.7%、52.8%和46.3%。无氟电解铝灰脱硫剂配方的脱硫效果最好,且用电解铝灰作脱硫剂原料可节省甚至无需氟化钙作助熔剂。     

Control of Ultra Low Titanium in Ultra Low Carbon Al-Si Killed Steel

 Titanium is the impurity in some special steel grades. The existence of titanium decreases the grain size, depresses the yield strength, and results in the low quality of these steels in various properties. Thus, titanium should be removed to the minimum. Based on the industrial production of ultra low carbon Al-Si killed steel, the physical-chemical behavior of titanium was investigated in vacuum degassing refining (RH) process with and without desulfurization. The influences of titanium content in hot metal, ladle slag composition, and ladle slag quantity, etc, on titanium content of refined liquid steel were discussed. The results showed that the partition ratio of titanium between ladle slag and liquid steel is in inverse proportion to the 4/3 square of aluminum content. The maximum partition ratio of titanium between top slag and liquid steel can be obtained by adjusting an optimum slag composition including contents of FeOx and Al2O3 and the slag basicity, and the suitable range of them should be controlled higher than 6%, less than 20%, and within 1. 5 to 3. 0, respectively. Moreover, desulfurization refining by RH decreases the partition ratio of titanium between ladle slag and liquid steel significantly. To ensure the titanium content stably less than 15×10-6 in a 300 t ladle, the titanium content in hot metal must be less than 500×10-6 and the thickness of basic oxygen furnace (BOF) slag carrying over must be less than 50 mm.     

Experimental Research on Refining Slag Systems Containing BaO for Ultra-Low Sulphur Steel

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Technical Study on Ultra-Low Sulfur Steel Production in Ansteel

Based on the fact of long period deep desulfurization treatment in LF,the relationships among top slag constituent in LF,molten steel constituent,stirring ability of blowing argon,molten steel temperature and desulphurization rate were analyzed.Through the experiments,the parameters about treatment technology of top slag in LF,the [Als] content in molten steel,slag charge match,molten steel temperature and the argon flow for stirring have been optimized.The desulphurization treatment period in LF can be shortened by 5～8 minutes.The target sulfur content in molten steel can be controlled below 30 ppm within one LF treatment period which is only 36 minutes.The LF treatment period of ultra-low sulfur steel can primarily match with the continuous casting period,multi-heat continuous casting can be ensured.     

碳铝顶渣改质剂在低碳钢生产中的应用实践

钢包顶渣的改质是防止钢水二次氧化、钢液深度脱氧、优化钢液和夹杂物去除的重要工艺方法.120 t转炉+LF+板材生产线生产低碳铝镇静钢SPHC和330CL时,LF精炼采用碳铝改质剂(/％:≥35Al2O3,15～30C,5～ 15Al,≤5SiO2,6～12CaF2)较无碳改质剂(/％:40～ 60Al2O3,≥20Al...     

采用LD-RH-CC工艺生产低碳铝镇静钢技术开发与实践

莱钢炼钢厂为了提高LD-RH-CC工艺生产低碳铝镇静钢技术水平,通过开发全工序低硫冶炼控制技术,构建RH环流模型,开发新型炉渣改质剂,开发连铸机无氧化全保护浇注工艺技术,提高了钢水洁净度,实现了LD-RH-CC工艺稳定控制。其中RH精炼炉终点硫的质量分数控制在0.006%,连铸机浇注炉数达到10炉以上,钢中氮、氧的质量分数达到0.02%以内,稳步推进RH精炼炉冶炼低碳铝镇静钢工艺技术发展。     

沙钢管线钢LF精炼的低成本深脱硫工艺

 根据沙钢对管线钢的生产需求及制造成本的控制,结合LF钢包精炼深脱硫的相关理论,开发了适用于管线钢的深脱硫精炼渣和低成本深脱硫工艺。使用该工艺,可完全不使用CaF2,只需使用石灰、铝脱氧产物和转炉下渣即可完成造渣,减少了石灰的消耗,降低了生产成本。180t LF生产实践表明:该工艺可将管线钢的硫含量稳定控制在10×10-6以下,精炼平均脱硫率高于85%。同时,该精炼渣具有较强的夹杂物吸附能力,精炼终点的非酸溶铝含量为（20~100）×10-6。     

Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out. For pre-treatment of hot metal, both desulphurization and dephosphorization are improved with the increase of CaO in slag, but deteriorated with the increase of CaF2 in slag. The average desulphurization and dephosphorization rate is 68.83% and 78.46 %, respectively. For molten steel, the sub-stitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization. The desulphurization and dephosphorization rate is higher than 90 % and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0. 001 2 % and 0. 010%, respectively. The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.