共查询到19条相似文献,搜索用时 171 毫秒
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利用计算机模拟技术,深入分析了电磁复合铸造轧辊的凝固过程。结果表明,电磁复合铸造轧辊的凝固是自下而上,由外向内的凝固过程。这种凝固方式既有利于金属补缩和夹渣的上浮,又有利于界面的充分熔合和元素的扩散,能够减少铸造缺陷,提高界面性能。 相似文献
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电磁复合铸造轧辊界面组织和性能研究 总被引:1,自引:1,他引:1
采用电磁半连续复合铸造装置浇注以45#钢为芯轴、高铬铸铁为耐磨层的复合轧辊。在保温时间为180~540s,研究了界面组织的形貌特征和微区元素分布,并测试了结合界面的力学性能。结果表明:电磁复合铸造高铬铸铁轧辊界面由扩散层和激冷凝固层组成;在本试验范围内,界面宽度为50~95μm;复合界面两侧发生成分扩散,其中Cr元素的扩散最明显;保温时间延长,耐磨层中的Cr向芯轴表层的扩散越来越充分;界面两侧显微硬度差别很大,但在界面处无突变;随着保温时间的延长,界面冲击韧性先小幅升高后缓慢下降,剪切强度先升高后缓慢下降;保温时间300s时,冲击韧性和剪切强度均达到最大值。 相似文献
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本文使用有限元方法对离心铸造复合铸铁轧辊凝固过程进行了数值模拟,建立了离心铸铁轧辊复合层凝固过程温度场模型。数值模拟技术可以从理论上预测凝固规律,并可辅助轧辊生产工艺设计,在此基础上研制了以MCS—51系列8031单片机为主控单元的微机化红外测温监控系统。该系统通过键盘通讯、数据采集及运算可以预报离心浇注机停机时间和温度,并可打印输出采样温度和时间,实现复合轧辊生产的微机监控。微机化红外测温监控系统已在生产中应用,防止了废品,有效地提高了离心铸造复合轧辊的质量,取得了良好的经济效益。 相似文献
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数值模拟轧辊复合层连续铸造,采用分段直线拟合曲线和控制容积法。提出连续铸造轧辊复合层界面良好熔合的判据。采用直接优选法,反推重要工艺。获得轧辊复合层连续铸造法生产装置的总体设计方案。模拟得到生产良好复合轧辊、漏钢等不同的生产工艺条件。 相似文献
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《稀有金属材料与工程》2016,(9)
采取不同外场施加方式进行半连续铸造以制备Φ165 mm AZ61镁合金锭坯,研究不同外场施加方式对AZ61镁合金锭坯晶粒尺寸和硬度的影响。结果表明,施加频率为30 Hz、电流为60 A的交变电磁场后,铸锭边部和中心平均晶粒尺寸由常规半连续铸造(DC)的248和276μm分别降至196和259μm,降低幅度分别达21%和6.2%,边部和中心晶粒细化程度明显不同;而施加超声-低频电磁复合场时,铸锭边部和中心平均晶粒尺寸分别降至185和208μm,降低幅度分别达25.4%和24.6%,中心区域晶粒细化程度大幅度提高。另外,与常规DC铸造相比,复合场铸造使合金铸锭的硬度提高且从铸锭边部到中心硬度差别明显减小。可见,超声场-低频电磁复合场半连续铸造显著改善了AZ61镁合金锭坯的内部质量,使凝固组织更加均匀、细小,硬度提高并分布均匀。 相似文献
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低频电磁水平半连续铸造中磁场的分布及其对宏观偏析的影响 总被引:1,自引:2,他引:1
采用数值模拟的方法研究了低频电磁水平半连续铸造7075铝合金中不同强度及频率的磁场在熔体中的分布,并采用试验的方法研究了不同条件的磁场对铸锭宏观偏析的影响.将使用传统水平半连续铸造生产出的铸锭与低频电磁水平半连续铸造生产的铸锭进行了比较.研究结果表明:在传统水平半连续铸造工艺条件下,铸锭中易出现较严重的负偏析及重力偏析;然而,在低频电磁水平半连续铸造过程中,低频电磁场的存在明显削弱了铸锭中的宏观偏析.此外,磁场在熔体中的分布情况将直接影响其作用效果,提高磁场强度及适当降低磁场频率均有利于对宏观偏析的改善. 相似文献
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Jian Zeng Roger Koitzsch Herbert Pfeifer Bernd Friedrich 《Journal of Materials Processing Technology》2009,209(5):2321-2328
The magnesium twin-roll strip casting process is investigated with a test caster at the IME. The flow field in the melt cannot be investigated optically, therefore numerical simulations have been undertaken to show the flow field in the Mg melt, the solidification between the two rolls and the cooling of the strip. The three-dimensional, turbulent flow field for different steady state casting points, in the process gap, have been calculated, including the solidification of the magnesium alloy melt. Within the process gap of the casting process the flow field shows similar flow structures. A big vortex in the casting channel and a much smaller vortex between the two rolls occur. With the increase of the casting speed the mushy zone is moved towards the kissing point. This can be interpreted due to a smaller force on the rolls. Nevertheless, the solidification on the rolls is so strong, that rolling between the two rolls happens. 相似文献
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W. W. Krysko 《工业材料与腐蚀》1966,17(3):235-238
Homogeneously lead-coated steel as structural material The author describes new apparatus for the manufacturing of homogeneously lead-coated plates. The apparatus is constructed on the principle of “inverted continuous casting”. By the conventional method of continuous casting, sheet material cannot be manufactured. The D. M. Process is only suitable for the making of foils. This new apparatus consists of two adjustable parallel rolls which revolve while half immersed in molten metal. The metal in contact with the cooling rolls solidifies and is squeezed between the rolls and emerges upwards as a metal sheet. A steel plate, which is introduced between the rolls, can be homogeneously coated on both sides with solidified metal, viz, in this particular cas, lead. The thickness of the coating is governed by the position rings on the rolls. The corrosion resistance of such homogeneously coated steel plates is described with the aid of examples from industry. 相似文献
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采用电磁半连续复合铸造法制成高钒高速钢35CrMo复合轧辊,研究了复合界面组织形貌特征和微区成分分布,测试了结合界面的力学性能。结果表明:界面上有厚度为40μm左右扩散层,层内显微组织为珠光体;邻接扩散层的合金钢侧组织为铁素体和珠光体,高速钢侧为马氏体基体上分布着VC颗粒。高速钢和舍金钢的显微硬度值分别为700HV和250HV,扩散层介于两者之间硬度值为350HV;冲击韧度值可达到100J/cm^2。该方法制备的复合轧辊界面具有良好的组织特征和力学性能,是冶金结合和扩散结合共同作用的结果。高钒高速钢35CrMo复合界面存在明显扩散层,且界面两侧发生成分扩散。结合区两侧显微硬度差别很大,但在界面处无突变。界面冲击韧度随高钒高速钢面积比的增加快速下降。 相似文献
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双磁力驱动器对液态金属流动的驱动与控制 总被引:3,自引:0,他引:3
根据电磁场和磁流体力学理论,设计制造了以永磁体为工作介质,对金属液具有磁力驱动控制作有的双磁力驱流体流动控制器。理论和实验研究结果表明:该控制器可实现对金属熔体无接触的磁力驱动搅拌;并可对弯月面形状和波动进行控制,当下磁力驱动器转速35r/s ,上驱动器转速20r/s时,液面平直且波动较小,即液面达到似稳状态;该实验条件下Sn+3.5%Pb(质量分数,下同)合金连铸凝固组织为100%细等轴晶,连铸坯的初期凝固点降低,凝固坯壳变薄且无效。 相似文献
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Yongsheng WANG ) Chenxi JI ) Jiongming ZHANG ) Xinhua WANG ) Wanjun WANG ) ) School of Metallurgical Ecological Engineering University of Science Technology Beijing Beijing China ) Shougang Group Beijing China ) Jiuquan Iron & Steel Co. Ltd. Jiayuguan China 《金属学报(英文版)》2009,22(5):345-352
Mathematical model of solute [C] distribution in twin-roll strip casting process has been setup successfully with Calcosoft for the first time. Simulation result shows that in the center of the molten steel pool between the two rolls there is a vortex flow, which is a solute enriched area. But the highest solute concentration position is at the solidification front of the columnar grain zone near the cooling roll surface. Another solute enriched position is in the back flow above the nip point. Combined wit... 相似文献