模铸保护渣的应用研究

本文阐述了保护渣的作用与特性，对低碳、中碳和高碳复合渣的应用进行了分析研究，形成了石墨渣系高、中、低碳系列保护渣。文中指出试制的以高炉水渣－电厂灰为基配制的复合可用于钢锭保护浇注。     

MC系列模铸保护渣的研究

本文介绍了MC系列模铸保护渣的广泛适应性和良好的使用效果。分析了该系列保护渣的特性,阐述了以电厂灰和硅灰石为基料,采用复合配碳,适当调整熔剂材料的种类和配比,使保护渣成分设计合理、理化性能优良、融熔结构稳定,按钢种、锭型和浇铸工艺的不同,实现保护渣系列化的理论依据和研究实践。     

鞍钢模铸保护渣的技术进步

本文着重叙述模铸保护渣的设计原则、模铸保护渣的一般要求、结构模型、配方、物性检验、保护渣的生产试验方法、生产应用、使用效果以及模铸保护渣的今后发展.总结了十年来,鞍钢在使用保护渣技术上取得的可喜进步,为提高成材率做出了应有的贡献。     

攀钢模铸用复合渣的研制与应用

针对炼钢模铸“三位一体”工艺存在的成本高，工艺复杂，污染环境问题，研制了一种新型铸钢用复合保护渣。将其应用于生产后，可简化操作，并具有安全可靠，减轻环境污染，降低铸钢成本等作用。     

模铸38CrMoAI用新型保护渣试验研究

本文论述了38CrMoAl钢对保护渣性能、成分设计、配方选择的要求,及新型保护渣配方设计及研制过程。对新型Z-2固体绝热型保护渣的理化性能及其使用效果与固体发热型保护渣进行了对比分析讨论,并对Z-2保护渣吸附夹杂能力和对钢成分的影响进行了热模拟研究,从而认定了Z-2保护渣的优越性。通过扩大试验和工业性试验生产的实践讨论,说明了Z-2保护渣具有良好的理化性能,适宜于38CrMoAl钢锭浇铸,并具有较好的经济效益和社会效益。     

模铸保护渣在含氮钢的研究与应用

通过对比BN-45(JJ)、BN-45、MS-1三种不同类型模铸用保护渣的软化温度、半球温度和流淌温度,并在含氮钢进行保护渣对比试验,甄选合适的保护渣,以解决该钢种出现的皮下夹渣、裂纹等缺陷。试验研究表明,三种试验保护渣的熔化温度与熔化时间由高到低依次为:BN-45(JJ)、MS-1、BN-45,熔化温度区间由大到小依次为:MS-1、BN-45、BN-45(JJ)。在相同条件下,通过三种保护渣的等量对比试验可知,BN-45(JJ)保护渣不适用于含氮钢的浇铸,而BN-45、MS-1两种保护渣在含氮钢上的使用效果良好,初轧坯低倍取样未见渗渣情况,盘圆矫直顺利,解决了钢锭皮下渗渣难题,并验证了优选合适品种的保护渣有利于提升产品质量与过程控制水平。     

连铸结晶器保护渣的熔化

１保护渣熔化过程和机理保护渣在钢水面上形成了所谓粉渣层－烧结层－液渣层的三层结构。保护渣熔化过程为：（１）试样中有机物氧化（脱水和汽化）；（２）碳质料的燃烧损失，时间较长，说明了渣粒烧结和熔化过程的延缓程度，与渣内所含碳粒类型和数量有关；（３）熔化突...     

Behavior of Mold Slag Used for 20Mn23Al Nonmagnetic Steel During Casting

 Because of the addition of significant quantities of Al and Mn, the great challenge of casting 20Mn23Al non-magnetic steel is to design a mold slag that is chemically compatible with this steel chemistry. In this paper, a new mold slag with low melting point, low basicity was proposed. The initial slag (the base mold slag) and two corresponding spent mold slag (8min slag and 15min slag), which was sampled from the caster after 8 minutes and 15minutes of casting, were investigated, the changes of mold slag composition and properties of molten slag were discussed. The results showed that:(i) The slag quickly changed in chemistry to a slag that contained a low quantity of silica and a higher quantity of alumina, and the basicity increased obviously; (ii) Heat flux density through the slag film decreased appreciably with the time increase; (iii) Mold slag used for non-magnetic steel precipitated CaF2 crystals; (iv) The slab has good surface quality with not occurrences of longitudinal face cracks and slag inclusions; (v) The Al2O3 content in the molten slag pool increased with time, and Al2O3 concentration of the pool can be regarded as being in a practically equilibrium state after about 600sec.     

Kinetic Analysis of Alumina Change in Mold Slag for High Aluminum Steel during Continuous Casting

A kinetic calculation model considering both a molten slag reaction with molten steel and an Al₂O₃ inclusion absorption in molten slag was developed to estimate the change in Al₂O₃ in molten slag during the continuous casting of high aluminum steel. Practical casting experiments of high aluminum steel were conducted to investigate the change in composition in the molten slag and to validate the proposed model. The calculated results show that the Al₂O₃ concentration in the molten slag increases quickly during the initial stage and gradually approaches a steady-state value after 900 seconds of casting, which agrees well with the experiment outcome. The change in Al₂O₃ in molten slag is mainly affected by the initial Al₂O₃ concentration w ⁰ of the mold powder, reaction equilibrium concentration of Al₂O₃ w* at the slag-steel interface, mass transfer coefficient \textk_{\textF,\textAl2 \textO3} {\text{k}}_{{{\text{F}},{\text{Al}}_{2} {\text{O}}_{3} }} in molten slag, Al₂O₃ inclusion concentration w _M , and absorption coefficient β in molten steel during continuous casting of high aluminum steel. The experiment result shows that the concentration of Al₂O₃ in molten slag increases significantly and that SiO₂ decreases strongly, while the other components in the molten slag can be negligible comparatively. Mold slag properties at 0, 5, and 45 minutes change greatly, which can deteriorate the performance of the mold slag.     

Inclusions in Runner Steel During Ingot Casting

This paper reported the observation of inclusions in the steel of an ingot runner. Thermodynamic modeling was performed to study the formation mechanism and sources of inclusions. CFD modeling on fluid flow, heat transfer, solidification of molten steel was carried out and the entrapment of inclusions in runner steel was predicted and compared with the measurement. Al2O3-based inclusions were the main ones in the steel samples. MgO?Al2O3 mainly stemmed from the lining refractory. The high MnO inclusions in the runner steel came from the runner slag. The effect of natural convection was very important for the cooling and solidification of the steel in the runner. Both the observation and the modeling show that > 50μm inclusions more accumulated on the upper area in the runner and < 50μm inclusions dispersed well and more accumulated on the lower area of the runner.     

Characteristics of Heat Flux Through Slag Film of Mold slag Used for High Al-TRIP Steel Casting

 Due to its high content in the Al-TRIP steel, [Al] reacts with (SiO2) in the mold slag during the casting process, which results in the increase of w(Al2O3)/w(SiO2) ratio and the Al2O3 content, respectively, the characteristic of heat transfer through the slag film is then changed, which effects the smooth operation of the continuous casting process. In this paper, the mold slag simulator was used to study the change tendency of the heat flux density through slag film and the results were discussed, at the same time, the crystals in the 15# slag were characterized by BSE and XRD. The results obtained show that:(i) Heat flux density decreases with the increase of w(Al2O3)/w(SiO2) ratio; (ii) Heat flux density increases with the increase of Li2O and/or B2O3 content in the mold slag which contain 30% Al2O3; (iii) Compared with the heat flux density of common slag of peritectic steel, an appropriated mold slag contain 4% B2O3 and 4% Li2O is designed. The heat flux density is 0.645MW&#8226;m-2 when w(Al2O3)/w(SiO2)=1.46. (iv) In the equilibrium state, mold slag used for Al-TRIP steel precipitates CaF2 crystals.     

Inclusions Generated during Ingot Casting of Tool Steel

An industrial trial study was carried out at Uddeholm Tooling AB, Sweden, to investigate the mechanisms of the formation of inclusions, especially macro inclusions during ingot casting. Strong evidence of reoxidation was observed. Two types of inclusions generated during casting were detected in the ingot. Inclusions of Type C1 originated from mould powder with reoxidation product Al₂O₃ as a part of it. Inclusions of this type were usually small. The number of Type C1 inclusions increased from the centre of the ingot toward the side wall of the mould. Type C2 inclusions were macro size. They could be the results of reoxidation and erosion of runner.     

20～27t 大型钢锭模的铸造

采用LF炉优化高炉铁水、树脂砂砂型铸造条件及阶梯水口浇注系统，生产制造出符合工艺要求的大型钢锭模。     

B25.6t镇沸两用锭型成坯率的统计分析

通过对Ｂ２５．６ｔ这一目前国内自行设计的最大锭型的成坯率进行统计分析，证明该锭型投入生产后，能有效地节约能源，提高设备生产能力，扩大产品规格等，可提高成坯率及成材率，收到显著的经济效益。     

Study on Magnetic Field Distribution in Electromagnetic Ingot Casting Mold for Extra Heavy Plate

The dual-frequency electromagnetic ingot casting(DFEMIC)method with copper water-cooled ingot mold for extra heavy plate was developed.Electromagnetic field distribution in ingot mold was measured through the teslameter,the shielding effect of the copper ingot mold was judged,it is less than 37.7%of magnetic flux density when there is no ingot mold.The average shielding the magnetic field proportion of copper ingot mold reduced to 54.9%after loading"「"pe the magnetic yoke and adjusting its distribution.Improving electromagnetic power can increase the magnetic field strength.Using the slit combination ingot mold could help increasing magnetic flux density in ingot mold.Steel structure outside ingot mold also have interference on magnetic field distribution in ingot mold,Therefore,it is important to paid more attention to electromagnetic shielding and the uniform symmetry of system structure.