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针对梅钢2号连铸机在浇铸包晶钢时出现漏钢报警率高的问题,在调查分析漏钢预报率高原因的基础上,通过对包晶钢保护渣的研究,开发出了梅钢2号连铸机包晶钢保护渣。工业生产试用表明,该试验渣性能稳定,在结晶器内使用状况良好,所浇铸坯表面质量良好,未发生漏钢报警现象。 相似文献
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板坯连铸机粘结漏钢与结晶器保护渣的关系 总被引:6,自引:0,他引:6
在板坯连铸机的漏钢事故中,粘结漏钢占的比例最大,粘结漏钢往往与所使用的结晶器保护渣有很大关系。结合鞍钢第三炼钢厂板坯连铸机多年来的生产实践,阐述了板坯连铸机粘结漏钢与结晶器保护渣的关系,并提出了一些防止漏钢的措施。 相似文献
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针对天钢集团公司的6流150mm×150mm方坯连铸机生产高硅含钒钢40Si2MnV时多次发生漏钢事故的现状,开展了稳定浇铸40Si2MnV钢水的工艺研究。通过分析,确定漏钢发生的主要原因包括Si在局部富集、结晶器保护渣性能异变和浇铸过程中结晶器冷却不均等。通过对精炼冶炼氩气供给制度、连铸冷却制度的优化及规范保护渣的保存与使用,得到了连浇22炉40Si2MnV钢水而未发生漏钢停流事故的较好效果。 相似文献
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统计了唐钢第二钢轧厂方坯连铸机2010年漏钢情况,分析了夹渣漏钢、粘结漏钢和角部裂纹漏钢的特点及机理,找出了漏钢产生的主要原因与保护渣的性能、结晶器的精度、钢水过热度、拉速、浸入式水口的对中、操作等因素有关,采取相应的改进措施后,铸机的漏钢率有了明显降低。 相似文献
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为改善唐钢中厚板厂船板钢的浇铸条件以及铸坯质量,将现场所用保护渣A进行调整形成保护渣B。基于相图平衡计算,采用光学显微镜对保护渣A和B在结晶器内的渣膜进行观察,研究渣膜结构对保护渣润滑和传热的影响机制。结果表明,保护渣A析晶温度和析晶率较高,析晶矿相主要为导热系数大的黄长石,渣膜中存在不均匀分布的气孔,使得铸坯向结晶器传热较快且不均匀,并恶化铸坯润滑,导致发生黏结漏钢,且铸坯出现裂纹,轧材合格率为98.73%。而保护渣B析晶温度和析晶率相应有所降低,渣膜结构分层明显,存在玻璃层,析晶矿相有适量导热系数小的枪晶石,有少量气孔,能有效控制铸坯向结晶器壁的均匀传热,并保证润滑铸坯,避免了黏结漏钢,且显著减少了铸坯裂纹率,轧材合格率为99.65%。 相似文献
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基于现场实测热电偶温度数据,将结晶器铜板温度及其变化速率进行2维可视化。综合考虑黏结形成和发展过程中结晶器铜板温度随时间的变化和空间传播行为,借助计算机图像处理中的8连通区域标记和边界跟踪算法,提取了异常区域的结晶器铜板温度、位置、时间等信息,计算了结晶器铜板温度变化速率的均值、最大值、区域的面积、宽度、高度及其纵向和横向移动速率特征,对实际浇铸过程中多例漏钢样本的共性特征进行了统计和归纳。结果表明,结晶器铜板温度变化速率、几何特征与传播速率能够作为黏结漏钢在线预报的重要判据,为提高漏钢预报系统准确率提供参考,减少漏钢事故,同时为结晶器可视化、智能化监控技术开发提供方法和依据。 相似文献
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对钢厂0.07%~0.18%C钢220~320 mm×1 800~2700 mm宽厚板的连铸过程进行了一年的在线检测与统计,研究了不同碳含量的钢种的拉速(0.65~1.2 m/min),钢水过热度(13~35℃),结晶器进水温度(27~35℃)和结晶器液位(775~810 mm)等工艺参数对结晶器铜板热流的影响。结果表明,浇铸220 mm板坯的结晶器热流随拉速增加而上升,但拉速>1.05 m/min时热流不再增大;对具有包晶反应的钢种,宽面与窄面热流随钢液过热度的增加而增大,但进水温度升高,热流降低;受包晶相变收缩的影响,浇铸0.13%C钢时结晶器热流最低。 相似文献
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R. B. Mahapatra J. K. Brimacombe I. V. Samarasekera 《Metallurgical and Materials Transactions B》1991,22(6):875-888
Axial heat-flux profiles have been determined quantitatively from temperature measurements conducted on a slab mold under
routine operating conditions. As in earlier studies, the heat flux was observed to have a maximum value at the meniscus and
to decline with increasing distance down the mold. The mold heat flux increased with increasing casting speed and was greater
with a mold powder having lower viscosity and melting point being applied as lubricant. The heat extraction was largest while
casting 0.29 pet carbon steel and least for a 0.09 pet carbon grade; reducing the depth of the submerged entry nozzle increased
the heat flux slightly in the upper region of the mold. Most significant was the higher heat flux observed at the meniscus
of the outside-radius face, attributable to the locally greater copper plate thickness compared to that of the opposite broad
face. All of the measurements can be explained straightforwardly by heat flow in the vicinity of the meniscus and the resulting
behavior of the so-called slag rim adjacent to the mold wall. It is postulated that the difference in copper plate thickness
between the two broad faces at the meniscus causes the slag rim to be smaller on the outside-radius face which gives rise
to shallower oscillation marks, as observed, higher heat transfer, and a slightly thicker solid shell. The dissimilar behavior
has implications for quality because the inside-radius shell, experiencing reduced heat extraction, cools and shrinks less
than the outside-radius shell. Thus, for a given end-plate taper, the narrow face of the slab adjacent to the inside radius
can push against the end plate, accelerating copper wear, and, owing to squeezing of the broad face, cause an off-corner depression
and subsurface crack toward the mold exit. If this is correct, maintenance of the same copper plate thickness at the meniscus
is fundamental to preventing such an occurrence. Moreover, adjustment of the heat extraction at the meniscus should be achievable
by changing copper plate thickness, mold coating thickness/conductivity, cooling water velocity, cooling channel configuration,
and mold flux composition for a given steel grade.
Formerly Graduate Student, Centre for Metallurgical Process Engineering, The University of British Columbia, 相似文献