共查询到17条相似文献,搜索用时 140 毫秒
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整体钢锭模生产锻造钢锭工艺的试验研究 总被引:1,自引:0,他引:1
根据凝固理论,采用整体钢锭镶绝热冒口套生产锻造镇静钢锭。整体钢锭模解决了钢锭悬挂裂纹问题,减少两道操作工序,防止了穿钢包模现象的发生,绝热冒口套良好的绝热保温性能使冒口钢水冒容比大大降低,提高了锭身质量,节约大量钢水。 相似文献
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钢锭冷凝过程仿真及试验研究 总被引:1,自引:0,他引:1
提出了直接对凝固潜热进行差分计算的一套计算方法,在此基础上开发了三维非稳态凝固传热的计算程序。应用该程序计算了包钢B96钢锭模内20钢钢锭冷却的温度分布和凝固率随时间的变化规律。根据理论计算的预报情况,进行现场工业试验。理论和现场两者相结合确定了最佳的镇静时间和开脱时间。 相似文献
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电站用汽轮机服役条件日益苛刻,对核心部件汽轮机转子锻件的要求亦日趋严格。文章列举了汽轮机转子锻件进厂复验中,轴颈无损检测超标缺陷分析的典型实例。论述了轴颈缺陷与大型钢锭凝固特征与偏析的关系;介绍了国外在改进转子大型钢锭冶金质量及开发新型转子材料方面所具有的先进生产制造技术。 相似文献
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以钢锭热过程一维无限长圆筒控制数学模型为基础,开发了均热炉群钢锭优化计算机控制系统,并采用美国爱克新公司生产的CIM-PAC分布式控制系统在马鞍山钢铁公司初轧厂实现了均热炉群钢锭生产过程的在线优化控制和管理。 相似文献
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钢锭系统热送热装热过程一维在线控制数学模型的研究 总被引:1,自引:0,他引:1
为了适应计算机在线控制的要求,利用“改进型田中功法”将“无限长二维矩型数学模型”转化为“无限长圆简一维数学模型”,建立了“钢锭系统热送热装热过程一维在线控制数学模型”。结果表明:对宝钢目前的钢锭热送热装系统而言,一维和二维数学模型计算结果的最大绝对误差为27℃、最大相对误差为2.30%,完全能够满足计算机在线控制系统对数学模型计算精度和速度的要求。所做工作对即将投运的“宝钢钢锭系统热送热装热过程计算机优化控制系统”具有重要的指导意义。 相似文献
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通过研究台车式退火炉的烟气流动情况,提出了影响烟气流动的关键因素是烧嘴和排烟口的位置,烟气在炉内的速度大小及分布对炉子的加热效率和钢锭的退火质量有重要意义。在此基础上,设计了一种新型的退火炉型,流场计算表明,该炉型具有省能、热效率高并能提高钢锭退火质量等优点。 相似文献
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为了对双辊薄带连铸自动控制系统铸速进行检测和控制,保持工艺稳定,提高薄带成品质量,建立了凝固终点位置与铸速的数学模型,对其相互关系进行了研究.研究结果表明铸速与凝固终点位置近似线性关系:铸速越大,凝固终点越靠近铸口且易断带或漏钢;铸速越小,凝固终点离铸口越远且易裂纹或轧卡.采用先进的热像仪对熔池与侧封板的接触面温度分布进行实时检测,确定薄带质量最优时的温度分布和铸速.在实际生产过程中,通过调整铸速即可影响熔池与侧封板接触面的温度分布,进而稳定凝固终点最优位置.试验证明了此模型的准确性. 相似文献
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为进一步提高Cr-Co-Mo-Ni齿轮钢材料的均匀性和细晶化,建立了直径290 mm的齿轮钢钢锭真空自耗熔炼过程三维数学模型,研究了熔炼工艺参数对钢锭凝固组织分布及晶粒大小的影响规律。结果表明:在工艺参数可调范围内,冷却强度越大,晶粒尺寸越小、数目越多,二次枝晶间距越小;熔池温度越低,晶粒的细化效果越好,二次枝晶间距也越小;降低冶炼速率,形核数目增多,晶粒尺寸减小,但对二次枝晶间距的影响较小。对齿轮钢真空自耗熔炼工艺参数优化调整后,模拟结果显示,自耗锭内部等轴晶区域增大将近一倍,晶粒尺寸得到明显细化;最大二次枝晶间距减小了4.88%,合金元素分布实现均匀化。 相似文献
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A two-dimensional mathematical model is presented to describe the solidification and cooling of liquid steel. The liquid steel is poured into a mold to obtain a solid mass of desired shape, called an ingot. After cooling of the steel in the mold for some time, the mold is removed. Then the leftover ingot mass is cooled in air. This article is concerned with the above process. Nevertheless, the technique can be very applicable to other processes such as continuous casting. Partial differential equations describing the process have been discretized using control-volume (or finite-volume) technique. The discretization equations obtained are of tridiagonal matrix form, which have been solved using the well-known tridiagonal matrix algorithm (TDMA) and the alternate direction implicit (ADI) solver. The model has been validated by measuring surface temperatures of molds and ingots using an infrared thermo-Vision scanner. This is then used to compute temperature distribution and solidification status of the ingot as a function of time and type of ingot. 相似文献
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T/P91钢焊接质量控制至关重要,从影响焊接质量的5个因素着手,结合多年来的焊接实践经验,分别阐述了人员、设备、材料、工艺、环境等方面的控制要点,指出了容易产生缺陷的关键点,并对不同焊接方法的质量控制过程进行了详述,分析了焊接工艺对接头性能的影响,最后对预防和消除不合格焊缝提出了控制措施. 相似文献
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The influence of the thermosolutal convection of the liquid steel in the solidifying core of a 3.3-ton ingot on the formation of banded mesosegregates is investigated by a multiscale solidification model. We first show how the thermosolutal flow structure in the solidifying core depends on the relation between the interacting thermal and solutal buoyancy forces and the coupling by the phase-change kinetics. We further show that banded mesosegregates are triggered by instabilities of the solidification front, that their location is determined by flow instabilities, and that their “A” or “V” orientation depends on the global direction of the flow circulation. Moreover, the results show that local remelting is not necessary to develop a channel mesosegregate. Destabilization of the mushy zone with local variations of the solidification velocity is sufficient. 相似文献
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J.W. ShurB.K. Kang S.J. MoonW.W. So D.H. Yoon 《Solar Energy Materials & Solar Cells》2011,95(12):3159-3164
A multi-crystalline silicon (Si) ingot was simulated and grown using the improved directional solidification (DS) process. Numerical simulations were performed with two different cooling paths and two different coolant flow rates in order to demonstrate the thermal characteristics in the improved DS furnace during the crystal growth. The temperature distributions in the furnace and locally (at the silicon ingot) were predicted as a function of time. From these result, a multi-crystalline Si ingot weighing 300 kg was grown within 40 h using the improved DS process. The Si ingot had a grain size that was larger than 5 mm, and the structure of the ingot was in the form of vertical columns. From the analysis results, the Si ingot exhibited a resistivity below 2 Ω cm and a life time above 3 μs. 相似文献
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针对板坯表面裂纹和内部裂纹两大类质量缺陷,基于凝固传热仿真、应力应变计算及连铸相关冶金工艺理论分析,并结合浇铸异常事件专家知识库方法,开发了CISDI板坯质量在线诊断分析数学模型及其应用软件CISDI_SQDS ONLINE R2011,其中引入裂纹生成指数来作为质量评级的参考理论指标,并在其计算过程中耦合考虑了与浇铸冶金准则密切相关的质量损失因子和异常事件对应的调节因子,实现了理论解析与专家系统的有机结合,为板坯质量的预测和控制提供了重要的理论工具,以期在板坯连铸生产中得以有效的推广应用。 相似文献