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坯壳应力引起的鼓肚变形是影响铸坯质量的重要因素,为防止过大的鼓肚变形,依据湍动能理论、热流传递理论和粘弹性理论,建立了异形坯三维热-力耦合模型,开发了鼓肚分析软件,从而避免了漏钢事故的发生.该模型将温度场和应力场的计算相互耦合,交替进行.结果表明:异形坯截面最危险点位于腹板中部,其次为翼板中点,在两者相结合的圆角部,由于凝固坯壳比较薄,其应力值也比较大;当坯壳厚度小于20 mm时,两点的鼓肚变形量将分别超过其极限变形量,铸坯出结晶器时必然发生漏钢事故.该模型通过预测坯壳应力和鼓肚变形量为现场安全生产提供了理论依据. 相似文献
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针对V微合金化高强异型钢在轧制过程中易出现翼缘裂边的情况,采用Gleeble 3800热模拟试验机对V质量分数为0.060%~0.080%的连铸坯试样在应变速率为1×10-3 s-1的试验条件下进行了700~950 ℃高温拉伸试验。通过对高温拉伸试样断口形貌、断面收缩率、抗拉强度及应力-应变曲线等的分析,得出试验钢的第III脆性温度区为750~875 ℃,不同变形温度下应力-应变曲线均表现为动态回复,并且随着变形温度的升高,曲线向下向左移动,最大应力对应的应变逐渐降低。因此,连铸生产时应优化配水模型,连铸坯入矫直机温度为900~950 ℃,以保证铸坯良好的表面质量。 相似文献
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Yuichi Motoyama Hiroki Takahashi Yuki Inoue Keita Shinji Makoto Yoshida 《Journal of Materials Processing Technology》2013,213(2):238-244
The load on flange castings in sand molds was gradually increased beginning from the end of the solidification process until the final cooling stage. The maximum tensile load on the flange castings in furan sand molds was larger than that of the flange castings in green sand molds. With the furan sand mold, permanent deformation in the flange castings occurred beginning from the end of the solidification process until reaching a temperature of approximately 250 °C. The mechanical interaction between the casting and the sand mold should be considered for more accurate stress calculations, particularly in furan sand molds. 相似文献
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通过建立1[∶]1异型坯结晶器物理模型,采用PIV粒子测速技术,研究断面尺寸为767.3 mm×383.1 mm×103.2 mm异型坯结晶器不同工艺参数条件和不同水口结构对结晶器内流场的影响。PIV实验结果表明,减小拉速和增大水口底部内径可以有效地减小冲击深度,结晶器深度860 mm处水口中心最大流股速度分别下降了27.96%和41.46%;增加拉速和减小水口浸入深度可以提高流场下旋涡上顶点位置。通过减小拉速和浸入深度,增大水口底部内径可以改善结晶器内流场。 相似文献
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为给型钢提供优质的铸坯,减少腹板裂纹、中心疏松等质量缺陷发生,研究了Q235B生产过程中的工艺条件,掌握了铸坯腹板裂纹和中心疏松产生的机理。通过控制钢水成分和洁净度、优化结晶器冷却及二次冷却工艺、优化保护渣工艺及水口插入深度等措施,保证铸坯在凝固过程中实现冷却均匀,降低铸坯表面温降,有效杜绝了铸坯表面腹板裂纹的发生,铸坯中心疏松等级控制在1.0以下。 相似文献
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A. Ohno 《JOM Journal of the Minerals, Metals and Materials Society》1986,38(1):14-16
To prevent the nucleation of crystals on the mold wall in the continuous casting of metals, a heated mold that maintained that temperature above the solidification temperature of the cast metal was used instead of the conventional cold mold. The cooling of the ingot was conducted outside of the mold. Heat was conducted axially along the ingot from the mold zone to the cooling zone. The principle of the O.C.C. (Ohno Continuous Casting) Process® was applied to the horizontal casting and vertical (upward) casting of wire and platelike ingots of Sn and Al. The ingots consisted of a completely unidirectionally solidified structure. It was possible to obtain a long single crystal ingot as a result of the growth competition of crystals. 相似文献
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利用铸造仿真软件ProCAST对铝合金电解阴极横梁金属型铸造过程进行了数值模拟,得到其温度场和应力场;分析了倾斜浇注竖直凝固铸件的应力场及位移分布.模拟结果显示阴极横梁应力集中位置主要在其两端过渡凸台端面连接处区域;铝横梁的变形方式为在纵向方向上类似S型变形.通过对铸件凝固过程热应力数值模拟可以更好地预测铸件凝固过程中应力和变形的动态变化,为实际生产提供科学指导. 相似文献
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万能轧机生产H型钢一般需要与产品形状相似的异形连铸坯作为原料。通过对万能轧机轧制H型钢时变形区的分析,提出轧制时腹板减少的金属一部分用于延伸,另一部分转移到翼缘,参与到翼缘的展宽和延伸。这样,降低了腹板的延伸系数,增加了翼缘的延伸量,使翼缘的变形与腹板的变形之间更加均衡。为此,设计了新的万能轧机粗轧机X孔型,提出了相应的水平辊和立辊的压下量控制方案。经实践,采用该方法降低了万能轧机机组对坯料的要求,即可以采用方坯或矩形坯,增加了万能轧机对轧件的控制能力,提高了生产效率。 相似文献
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EXPERIMENTAL RESEARCH AND NUMERICAL SIMULATION OF MOLD TEMPERATURE FIELD IN CONTINUOUS CASTING OF STEEL 总被引:1,自引:0,他引:1
X.S. Zheng M.H. Sha J.Z. Jin 《金属学报(英文版)》2006,19(3):176-182
Mold is the heart of the continuous casting machine. Heat transfer and solidification in a water cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of casting speed and water flow rate on the mold temperature field were also discussed. 相似文献
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传热过程决定着板栅连铸结晶器能否连续稳定地生产出合格质量的连铸板栅,根据热力学第一定律和傅里叶定律(热传导定律)对板栅连铸结晶器的热量传递进行了研究。依据板栅连铸结晶器实际结构简化模型,分别建立了冷却油、端盖以及空气稳态复合传热模型,高温铅液、连铸动模外筒以及冷却油的稳态复合传热模型,连铸动模内部冷却油的放热计算模型,进而建立了板栅连铸结晶器传热动态平衡方程;为了指导生产实际,建立了运行过程操作函数。通过板栅连铸结晶器传热过程的分析研究,对提高板栅连铸的连续稳定生产并实现板栅连铸结晶器的全自动温度控制具有一定的指导意义。 相似文献