共查询到17条相似文献,搜索用时 296 毫秒
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连铸结晶器内大方坯的热力耦合分析 总被引:1,自引:0,他引:1
针对攀钢大方坯连铸机投产初期铸坯表面角部纵裂缺陷,建立了大方坯连铸结晶器内铜板与铸坯问的热力耦合模型,应用模型分析了大方坯连铸结晶器内的传热过程和坯壳的应力分布.在传热模型中,以稳态模型分析结晶器的传热过程,以瞬态模型分析铸坯的传热过程;在力学模型中,考虑铸坯和结晶器的接触边界以处理结晶器角部的气隙,以热弹塑性模型分析铸坯的变形和应力场.2种结构的连铸结晶器中大方坯温度场和应力场计算结果表明,结晶器倒角从25 mm×45°变为12 mm×45°时,可改善铸坯角部的传热条件,降低凝固坯壳角部温度,增加凝固坯壳厚度,有利于减轻和防止铸坯角部裂纹. 相似文献
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以宝钢厚板连铸机结晶器一冷传热过程为研究对象,结合高温铸坯在结晶器内的实际热量传输规律,建立了宝钢厚板连铸机结晶器凝固和传热模型.结晶器内凝固传热过程分为凝固坯壳传热、缝隙间传热和结晶器铜板传热,其中结晶器缝隙问传热模型综合考虑了气隙、保护渣和振痕对传热的影响.利用Fortran语言对模型进行编程,开发出相应的结晶器凝固和传热仿真软件Moheat.结合厚板连铸机结晶器生产数据,对模型进行了验证.所得计算结果符合实际测量值.利用该软件能够对不同生产工艺下的凝固坯壳厚度、坯壳表面温度、结晶器铜板温度、冷却水温差以及结晶器理想锥度等进行计算,分析和优化结晶器一冷制度,指导连铸生产. 相似文献
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通过建立传热模型,研究了板坯结晶器的传热行为.模型的建立考虑到结晶器内湍流运动对过热度分布的影响,提出了耦合流场和温度场求解坯壳热流密度,并将其导入传热模型计算的方法.模型包括凝固坯壳,结晶器缝隙和铜板的传热,其中计算结晶器缝隙间热量传递过程中,综合考虑了振痕、固渣层、液渣层和气隙对传热的影响,并做了相应处理.模型能根据不同的生产工艺(不同断面形状和尺寸、拉速等),对凝固坯壳厚度,表面温度,结晶器铜板温度,冷却水温差,以及结晶器理想锥度等进行计算.结合宝钢3号连铸机结晶器生产数据,对模型进行了验证,所得计算结果符合实际测量值. 相似文献
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建立小方坯喷淋结晶器凝固传热数学模型,模拟计算了铸坯温度场、坯壳厚度、热流场,坯壳与铜壁间气隙厚度。计算坯壳厚度与实测坯壳厚度基本吻合;与普通水缝式结晶器相比,铸坯温度场均匀,坯壳厚度均匀,冷却强度有所提高。 相似文献
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基于传热与流动的耦合模型,分析研究了水口形状对异型坯结晶器出口坯壳厚度的影响.结果表明:采用直通型水口时,结晶器高度方向450~550mm时钢液冲刷严重,使得凝固的坯壳发生重熔现象,从而导致此处结晶器出口坯壳较薄;采用侧开孔型水口时,在结晶器上部,尤其在结晶器高度方向200mm以上,由于钢液的冲刷,腹板中心和翼缘角部没有形成一定厚度的坯壳,而在300mm左右坯壳逐渐形成并和已凝固坯壳连接到一起,随着结晶器高度的增加,结晶器内形成的坯壳厚度也逐渐增厚,在结晶器出口坯壳的厚度也较均匀. 相似文献
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小方坯连铸机结晶器的研究 总被引:5,自引:1,他引:4
本文建立了铸坯凝固传热数学模型,模拟计算了铸坯温度场、坯壳厚度、热流场、坯壳热收缩应力场、坯壳与铜壁间气隙厚度;计算出的坯壳厚度与实测的坯壳厚度基本吻合,计算结果可为连铸机生产和连铸机设计提供参考。 相似文献
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建立了铸坯固传热数学模型,模拟计算了铸坯温度场,坯壳厚度,热流场,坯壳热收缩应力场,坯壳与铜壁间气隙厚度,计算坯壳厚度与实测坯壳厚度基本吻合,计算结果为连铸机生产,连铸机设计提供参考。 相似文献
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A. Nájera‐Bastida R.D. Morales L. García‐Demedices R. Zárate‐Gutiérrez J. Rodríguez‐Ávila 《国际钢铁研究》2011,82(4):301-312
Effects of mold powder chemistry on shell growth and thinning have been studied using Computer Fluid Dynamic techniques under conditions of constant casting speed and steel superheat for a peritectic steel in a billet caster. Two mold powders were considered; a basic powder suitable for peritectic steels and an acid powder not recommendable for this steel in order to emphasize the importance of chemistry on shell stability. Numerical results indicate a strong interaction between powder composition and steel flow‐heat transfer phenomena. The acid powder creates recirculating flows at both sides of the entry jet that transport sensible heat to the shell inducing its remelting and thinning leading, eventually, to a strand breakout. Meanwhile, the basic powder induces a single recirculating flow in the internal radius side of the mold without severe shell thinning. A colder meniscus is predicted using the acid powder which is in agreement with the casting practice experience. Powder infiltration of the basic powder in between the mold hot wall and the strand provides a powder shell with a macroscopically smooth surface while the acid powder yields irregular infiltration. Buoyancy forces along the mold working height and mold curvature play a fundamental role on the generation of the recirculating flows. Interaction between powder chemistry and fluid flow‐heat transfer are two‐way coupled phenomena that must be considered for powder design purposes. 相似文献
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Analysis of the nonuniform slag film,mold friction,and the new cracking criterion for round billet continuous casting 总被引:1,自引:0,他引:1
A method predicting the thickness of solid and liquid slag films is presented to understand the complicated heat transfer
from the strand to mold for round billet continuous casting. A mathematical model is also developed to calculate the liquid
slag lubrication and solid slag friction on the basis of mechanics of viscous fluids and the contact state between the solidifying
shell and mold. And a new criterion, based on the nonuniformity of mold heat transfer around the perimeter is proposed to
predict the longitudinal crack. The results show that in the upper mold the distribution of the thickness of liquid slag film
is similar with that of the solid one, and both of them are nonuniform around the mold perimeter, so does the mold friction.
Increasing the casting speed could advance the time of crack formation for one casting process. By comparison, the sensitive
area of the longitudinal crack predicted by the new criterion corresponds to that by a stress-based crack criterion. It may
lay the theoretical foundation for the on-line detection of billet quality and the visualization of the continuous casting
mold process. 相似文献