提高连铸生产能力的措施与效果

铁水增多所导致的转炉生产节奏加快以及连铸机改造后差异性的扩大,使宝钢分公司第一连铸分厂的产能压力和生产组织难度增大。为此,优化了连铸生产组织,并从连铸机生产计划的分工、工序和生产线交叉、特殊钢种的生产组织、中间包利用最大化、浇铸速度和异钢种连浇的优化等方面,提出了提高连铸产能的措施,且实施后取得了明显效果,连铸日浇钢增加了2.4炉。     

提高连铸生产能力的措施与效果

铁水增多所导致的转炉生产节奏加快以及连铸机改造后差异性的扩大,使宝钢分公司第一连铸分厂的产能压力和生产组织难度增大。为此,优化了连铸生产组织,并从连铸机生产计划的分工、工序和生产线交叉、特殊钢种的生产组织、中间包利用最大化、浇铸速度和异钢种连浇的优化等方面,提出了提高连铸产能的措施,且实施后取得了明显效果,连铸日浇钢增加了2.4炉。     

Development of indices for quantification of nozzle clogging during continuous slab casting

Abstract

Deposition of alumina inclusions inside the submerge entry nozzle is a long standing problem in continuous casting of aluminium killed steel. Clogging of the casting nozzle severely affects productivity and also causes degradation of product quality. Unfortunately, very few numerical tools are available for precise quantification of the magnitude of clogging. Tools for quantifying the extent of clogging were developed during the present work and have been integrated with the control system of a running continuous slab casting shop. Reasonable match has been observed between the estimation from the developed program and the actual observations in the casting shop and subsequent products. In addition to process control, the tools were also found useful for comparing the castability of different steel grades. This feature has been utilised to study nozzle clogging during casting of steel grades that are commonly believed to have poor castability.     

Determination of the hardness and the mechanical properties of steel during melting,secondary refining,and continuous casting in an arc-furnace shop

The density and the ultimate tensile strength of steel are studied during melting, secondary refining, and continuous casting in an arc-furnace shop.     

Development of the continuous casting of steel at the Chelyabinsk Metallurgical Combine

In 2007, the electric steelmaking shop at the Chelyabinsk Metallurgical Combine operated with two continuous slab casters made by Uralmash, while the oxygen converter shop had two continuous section casters made by the Danieli company. It was decided that the two Uralmash casters will be replaced by a single Danieli caster. The shop has also mastered a technology for casting corrosion-resistant, reinforcement-grade, pseudo-rimming, and low-and medium-carbon steels. Plans call for further expansion of the range of grades of steel that can be cast.     

Empowerment with knowledge— toward the intelligent mold for the continuous casting of steel billets

A never-ending challenge to the competitiveness of the steel industry is the application of knowledge on the shop floor where, finally, productivity and quality are realized. The impedi-ments to the effective implementation of knowledge are largely people related and range from the level of education of the work force to entrenched attitudes of management. The develop-ment of the continuous-casting process for the production of steel billets, upon which this lecture focuses, is but one example. Looking back over 20 years, it is clear that the billet industry, in its infancy, was in a state of confusion, operating without casting standards coupled to quality, such that individual companies had developed very different practices. Research over 2 decades has established the knowledge base for the continuous casting of quality billets and set much needed standards for the design, operation, and maintenance of casting machines. The challenge now is in knowledge transfer and implementation with the aid of expert systems. Thus, the expert system for continuous casting and the concept of the intelligent billet casting mold have evolved to transcend other forms of knowledge transfer like publications and short courses. The intelligent mold effectively transfers knowledge on line to the shop floor through the combi-nation of sensors (thermocouples and load cells), signal recognition based on years of research, mathematical models of heat flow in the solidifying shell and mold, understanding of the mech-anisms of quality problems, and the formulation of a response to a given set of casting con-ditions, all controlled by an expert system. In this lecture, the drive to develop, transfer, and implement knowledge on the continuous casting of quality billets is explored. Lessons for the future are drawn from successes, failures, and frustrations in the past.     

20Mn23AlV钢用低反应性连铸保护渣的开发

20Mn23AlV高锰无磁钢的高铝含量导致连铸过程中钢水与连铸保护渣的剧烈反应,连铸坯产生大量裂纹缺陷,影响其连铸正常生产。为提高铸坯质量,保证20Mn23AlV高锰钢连铸生产顺行,本研究对现场生产20Mn23AlV的连铸工艺和采用的连铸保护渣进行了系统的研究和分析。通过实验室的感应加热炉进行渣-金反应试验,并结合化学分析和扫描电镜等方法研究开发出20Mn23AlV低反应性连铸保护渣,并采用工业试验证明采用低反应性连铸保护渣可以消除连铸坯表面裂纹缺陷,20Mn23AlV高锰钢铸坯修磨量可由8%降低至1%。     

Reaching the Design Capacity of a Continuous Section Caster

A new growth strategy has been devised for the West Siberian Metallurgical Combine. The cornerstone of the plan is the reconstruction of the combine's steelmaking facilities, which will involve a complete changeover to continuous casting. Oxygen-converter shop No. 2 is the first shop to be rebuilt. In October 2002, the shop added a continuous section caster with a nominal capacity of 1.2–1.4 million tons of continuous-cast semifinished products a year. The caster reached this level of output in September 2003 (11 months after startup). The design parameters of the caster were attained thanks to a combination of technological, technical, and organizational factors: development and optimization of new technologies for steelmaking, out-of-furnace treatment of the steel, and continuous casting; optimization of the steelmaking-casting schedule; modernization of the caster's equipment. The addition of a “ladle-furnace” unit and reconstruction of the main components of the caster will boost its capacity beyond the original limit, which will in turn allow the combine to make competitive, high-quality products and react quickly to changes in the market.     

Solidification and microstructure of a high alloy stainless steel

The steel considered in the present work can be classified as a 6Mo austenitic stainless steel, which has a much higher corrosion resistance than many other commercially available stainless steels. However, because of macrosegregation during solidification of ingot casting, the high alloy content in the steel, especially Mo, N, C, enhances precipitation of intermetallic phases such asa phase. Such precipitation mainly occurs in the center of the material and has normally no significant effect on mechanical properties or surface corrosion resistance. The introduction of modern production methods such as continuous casting of slabs for stainless sheet production has reduced the macrosegregation tendency and related precipitation. However, the microsegregation in a small scale may be enhanced as the higher cooling rate prevents the diffusion in the solidified region. In the present work, the continuous casting solidification process was simulated in a laboratory gradient     

“十三五”中国炼钢关键技术进步及思考

“十三五”时期,中国炼钢技术快速发展,在机理创新、关键工艺技术和装备研发、高品质钢高效生产、智能化控制、低碳绿色发展等方面都取得了长足的进步。中国粗钢产量持续增加,达到了世界产量的56.49%,在发展的同时逐步实现炼钢结构优化,高品质钢的高效绿色生产为中国经济高速发展提供很好的支持作用。通过回顾和分析“十三五”期间中国炼钢共性关键技术取得的科技成果,对“十三五”期间炼钢科技进步进行了总结。代表性关键技术成果总结为两个方面,即“高品质钢炼钢-连铸关键技术开发与应用”和“洁净钢高效、低碳绿色炼钢-连铸技术研发”。“高品质钢炼钢-连铸关键技术开发与应用”技术主要的发展表现在高品质不锈钢脱氧及夹杂物控制技术,薄板坯连铸连轧生产电工钢技术,重载车轴钢冶金技术,高速和重载铁路钢轨用钢炼钢技术,特殊高合金钢品种冶炼及连铸关键技术;“洁净钢高效、低碳绿色炼钢-连铸技术研发”的主要发展体现在大型转炉高效、绿色冶炼关键技术,绿色电炉高效冶炼技术,高品质特殊钢绿色高效电渣重熔关键技术,高品质钢高效连铸技术。同时,炼钢-连铸智能化控制技术的应用取得了进展。实现关键钢铁材料的自主保障和前沿技术的突破是“十四五”...     

钢铁生产连铸连轧新工艺

介绍近年来世界钢铁生产工艺中出现的连铸连轧新工艺,以及连铸连轧工艺发展的状况,并以ＣＳＰ和ＩＳＰ两种类型薄板坯连铸连轧为例进行了阐述,最后就我国连铸连轧的发展情况也进行了介绍,指出ＣＳＰ和ＩＳＰ生产技术是中小型钢厂的发展方向     

高碳钢连铸工艺优化

阐述了影响高碳钢(碳含量在0．40％以上，以捆带钢为例)连铸生产质量的因素。通过生产组织优化给出了高碳钢连铸生产顺行的方案；通过生产工艺对比试验优化了高碳钢冶炼成分及连铸工艺参数；通过试验重点阐述了钙对高碳钢内外部质量的影响；研究开发了适合高碳钢连铸专用保护渣。     

Extending the life of the tundish and lining of the intermediate ladle in a six-strand continuous bar-casting machine

Continuous steel-bar casting on a multistrand machine in superlong series is limited by the working-layer wear of the intermediate ladle’s lining within the slag band and the region of jet incidence. The lining life may be significantly increased by using high-strength concrete tundishes of special geometric shape, taking account of the specific ladle and the casting conditions. A fundamentally new metal-intake design for the casting of superlong series at multistrand continuous bar-casting machines is investigated. In the converter shop at OAO Enakievskii Metallurgicheskii Zavod, a casting series of maximum length 64 melts proves possible. This corresponds to the casting of 9300 t of steel from a single intermediate ladle. For optimal organizational and technological conditions, increase in this characteristic by a factor of 1.5–1.6 may be expected.     

板坯连铸结晶器非稳态流场的模拟研究

本文运用数值模拟研究方法,研究高拉速厚板坯连铸非稳态结晶器流动特性,研究浸入式水口堵塞、水口不对中对结晶器流场、液面流速和对初生坯壳的影响。高拉速厚板坯连铸,铸坯质量下降,90%表面缺陷集中在铸坯边角区域,最严重的缺陷是铸坯中心和角部纵裂。非稳态工况对结晶器的流场影响因素更为显著,研究发现水口堵塞程度、水口出口流速、流量分配比是结晶器液面流速不对称、液面波动的主要影响因素,水口不对中是钢液流股对结晶器初生坯壳局部热冲击的主要因素,因此高拉速连铸应尽量避免非稳态工况操作,确保产品质量和效率的双赢。     

Controlling Nozzle Clogging by Secondary Steelmaking Without Reheating

Ever since continuous casting was introduced, nozzle clogging has been a recurring subject of metallurgical research and publications. Nozzle clogging is caused by the deposition of non‐metallic inclusions – on the casting equipment – which are solid at the temperature of casting. Calcium treatment already represents a possible solution to eliminate this phenomenon, but there are special steel grades which do not allow its application either because they are price sensitive or for certain other reasons.³ Cleaning the steel melt by agitation is an alternative solution, but it has time constraints due to the cooling of the melt. Over extensive cooling can be prevented by heating the melt (in ladle), but its introduction and operational costs per heat are often too high for an individual steelmaking plant to afford. The goal of our research is to find metallurgical solution to reduce the rate of nozzle clogging in plants which do not possess a ladle furnace and the time devoted to treatment or the price of the product do not allow Ca‐treatment to be applied.     

连铸工艺生产铁道车轴钢力学性能及质量控制

 连铸工艺生产车轴钢具有高效、经济、质量优等特点,为了满足铁道部门对高质量车轴钢坯的需求,开展了大方坯连铸工艺生产铁道车轴钢的试验研究。针对连铸生产车轴钢的技术条件要求,研究了微量元素钒在车轴钢中的作用,利用钒的析出强化,显著提高了车轴钢的力学性能指标,其强度稳定提高10%,并具有良好的塑韧性。用户加工车轴的力学性能及实物质量优良,完全满足连铸技术条件及铁道运输的发展需要。     

Rebuilding the secondary cooling system on the continuous slab caster at the Kamastal’ Metallurgical Plant

A new system has been developed for the water-air cooling of ingots. The system functions in the automatic regime, including during transients in the casting operation. It increases casting speed and improves the quality of both the surface and the macrostructure of the slab. The cooling system developed for low-speed continuous casters provides for low-intensity cooling of the slab by a water-air mist, which prevents local overcooling of the part of the ingot surface that first comes into contact with the coolant water. The system has passed factory tests and has been adopted for use on all of the grades of steel made in the shop.     

大型板坯连铸机漏钢分析和控制

通过对武钢二炼钢厂2号大板坯连铸机漏钢原因的分析，得出结晶器内弧铜板振幅小、结晶器偏摆超过标准要求、保护渣水分超过0．5％、操作不当等是造成漏钢的主要原因。通过对连铸机设备精度、保护渣质量等进行动态监控，稳定铸温和铸速，调整振动机构使结晶器内弧振幅达6．8mm，偏摆降至0．2mm，使漏钢率由2002年的0．093％降至2003年的O．019％。     

连铸机钢水流动性差的原因分析与改进

针对连铸机新开浇次前期钢水流动性较差问题,对新开浇次水口堵塞物检测分析,发现其主要原因是钢水温度高、钢水二次氧化严重、中包冲刷等。通过采取提高中包开浇时液面,增加前4炉精炼炉渣量、延长LF处理周期、制定连铸机开浇操作标准化等技术措施,有效地改善了新开浇次钢水流动性。     

Numerical Simulation of Influence of Casting Speed Variation on Surface Fluctuation of Molten Steel in Mold

The influences of casting speed variation on surface fluctuation of the molten steel in mold during continuous casting were investigated with numerical simulation method.It was found that when the casting speed was evenly decreased from 1.4 m·min-1 to 0.6 m·min-1,the increase of the surface fluctuation of the molten steel in mold was observed only on time that was at the start of casting speed change.While,in experiment of increasing casting speed evenly from 0.6 m·min-1 to 1.4 m·min-1,the increase of the surface fluctuation of the molten steel in mold was observed only at the time when the casting speed was stopped to increase after it had been increased to 1.4 m·min-1.For surface fluctuation of the molten steel in mold which was produced during the casting speed evenly increasing or decreasing period and at the time when increasing or decreasing the casting speed at low casting speed level(0.6 m·min-1),the influence of casting speed change is very small.In addition,it is found that,at high casting speed level(1.4 m·min-1),even a little change of casting speed could result in remarkable increase of the surface fluctuation.Thus,at high casting speed,changing casting speed should be avoided or much slower speed changing rate should be used.