共查询到20条相似文献,搜索用时 109 毫秒
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分析了板坯产生角部横裂纹的诸种原因,包括结晶器冷却强度、结晶器液面波动、设备精度等,通过相应措施的实施,铸坯角部横裂纹得以控制。 相似文献
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针对舞钢1 900 mm板坯连铸机生产连铸坯角部经常出现的横裂纹,从连铸坯裂纹产生机理和影响因素角度进行分析,最终确定铸坯角部矫直温度过低以及边部存在凹陷是角部横裂纹产生的主要原因,对此提出了预防措施。通过结晶器锥度、一冷水、二冷水等工艺参数优化及设备改造,有效地控制了连铸坯角部横裂纹的产生。 相似文献
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以控制铌、钛微合金化钢板坯角部横裂纹为目标,在马鞍山钢铁股份有限公司板坯连铸机上开发并应用倒角结晶器技术。建立三维稳态传热模型,采用数值模拟的方法研究了倒角结构对连铸坯角部温度的影响,通过工业试验对比分析了不同角部形状板坯角部横裂纹的控制效果。数值模拟结果表明:铸坯角部由直角变为钝角后,角部温度明显提高;距弯月面900mm处,角部温度由788℃提高到1 091℃以上,铸坯宽面角部的角度分别为120°,125°,127°时,其角部温度依次为1 091,1 128,1 110℃,相应地铸坯窄面角部的温度依次为1 254,1 240,1 209℃。工业试验结果表明:采用倒角结晶器和二冷弱冷工艺后,角部横裂纹得到了有效控制,铸坯宽面角部的角度为125°时,角部横裂纹发生比例最低,铸坯质量满足热送直轧要求。 相似文献
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板坯连铸倒角结晶器的开发与应用 总被引:2,自引:0,他引:2
为减少连铸板坯角部横裂纹,在分析连铸坯角部横裂纹形成机制的基础上,提出了通过倒角结晶器减少角部横裂纹,以改变连铸板坯角部的二维传热,提高矫直时连铸坯的角部温度。数值模拟计算的结果表明,相对于直角连铸坯,倒角连铸坯在矫直区连铸坯角部温度明显提高,消除了角部Z向应力和应变集中。工业生产数据表明,采用倒角结晶器后,矫直区连铸坯角部温度从810~855℃提高到901~932℃,有效避开了钢的高温脆性区,连铸坯角部横裂纹发生率从10.6%稳定控制到1.6%以下,显著减少了连铸坯角部横裂纹。目前倒角结晶器稳定应用于首秦,所生产钢种涵盖了普碳钢、低合金钢、低碳钢和中碳含铌钢等。 相似文献
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宝钢连铸板坯角横裂缺陷的改善 总被引:4,自引:1,他引:3
介绍了影响包晶碳钢角横裂的连铸工艺操作和设备。在过去的几年中,集中采取了一系列的措施,改善钢水在结晶器内和二冷区的冷却条件,减少作用在凝固环壳上的机械应力,使得角横裂缺陷发生率明显减少。 相似文献
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《钢铁研究学报(英文版)》2011,(Z1):557-562
In order to reduce the transverse corner cracks of high strength weathering steel Q450NQR1,the factors influencing transverse corner cracks on continuously cast slab,such as level fluctuation of molten steel in mold,mold taper,primary cooling,mold powder,secondary cooling,nitrogen content in steel,spray nozzle structure,processing parameters and equipment of CC,etc.,were analyzed.Based on this,a series of comprehensive countermeasures have been proposed.The operation shows by the use of key technologies,including stabilizing steel level,optimizing the mold taper,weakening the primary cooling and the secondary cooling,reforming the mold powder,and adjusting spray nozzle structure,the transverse corner cracks on continuously cast slab have been significantly reduced,and the edge cracks on hot rolled sheet have been eliminated due to the transverse corner cracks.The qualified slabs are delivered to produce weathering cold forming sectional steel,whose yield strength is greater than 450MPa. 相似文献
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Aldo Ramacciotti 《国际钢铁研究》1988,59(10):438-448
Starting from a structural analysis of a solidified shell in a continuous casting conventional mold, the author developed a model that has now been adapted to simulate the solidification process also in the case of a funnel-shaped mold proposed for continuous casting of thin slabs. A rating of possible critical conditions in the stress level, suitable for producing cracks in longitudinal or transverse directions, is given by means of two separate cracking indices: L.C.I. (longitudinal cracking index) and T.C.I. (transverse cracking index). An analysis of the effect of a few variables on the basis of a total of 9 simulation runnings in different conditions, gave for the funnel-shaped mold the following summarized results: In comparison with a prismatic mold, casting at the same casting rate (2 m/min) and for the same product dimensions (50 mm × 1 000 mm), the funnel-shaped mold behaves similarly in the corner area but less well in the center of the broad face where longitudinal cracking susceptibility is concerned. However, no significant differences result concerning transversal cracking susceptibility. Cracking risk, both transversal and longitudinal, diminishes tremendously with increasing casting rate. Cracking susceptibility when employing the funnel-shaped mold is very sensitive to small variations in the “shape” of the curved mold walls, particularly for longitudinal cracking. The effect of changing taper is not large as the gap on the short side of the mold is preserved. When the gap, on the short side, as a consequence of an excessive taper, almost disappears, in some part of the mold a great pressure concentration on the same side in the corner region is produced. The drawing action, arising on the shell because of friction, results in high shear stresses and possible cracks at the corner. Limits and reliability of the model, which depend on knowledge of high temperature steel properties, are discussed. 相似文献