共查询到20条相似文献,搜索用时 203 毫秒
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采用规格为φ250 mm x 150 mm的立式双辊连铸系统制备了3~4 mm厚、150 mm宽的AZ61镁合金薄带坯;研究了水口形状和浇铸温度等连铸工艺参数对薄带坯显微组织和表面质量的影响.结果表明:采用B型水口制备的AZ61薄带坯的表面裂纹较少,表面质量较好;随着浇铸温度的降低,薄带坯表面裂纹数量增多,AZ61薄带坯的组织由先析α-Mg和过饱和α-Mg基体组成;当浇铸温度为630℃时,薄带坯的组织细小均匀;当浇铸温度介于固相线和液相线之间时,薄带坯组织中存在局部粗大的α-Mg树枝状晶. 相似文献
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液压事故闸板误动作事故分析 总被引:1,自引:1,他引:0
1前言 某公司圆坯连铸机主体设备和工艺技术为国外引进,是一套具有国际20世纪90年代先进水平的连续铸钢设备。该连铸机生产的优质连铸圆坯可用于轧制火车车轮、火车车轮轮箍、管材线材等产品。该机的中间罐水口开闭由塞棒控制.为了防止当塞棒装置失灵时,钢液失控而烧坏中间罐下面的结晶器、振动台等设备,在中间罐水口部位设置了事故闸板装置,当塞棒装置故障而不能关闭水口时,可以操作事故闸板装置将水口关闭。但是在一次正常浇铸时.事故闸板装置却错误地将中间罐水口关闭。浇铸被迫停止.造成了一起断浇事故. 相似文献
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大包水口液压系统是连铸机上的重要设备,大包的水口通过液压缸的开启,使钢水浇人中包,实现连续铸坯的第一道工序.大包水口液压控制既降低了工人劳动强度,又提高了设备自动化程度,为快节奏、高效率铸坯生产打下坚实基础. 相似文献
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针对目前传统抓胎机械手在取胎过程中易发生胎坯变形不对称和变形量大的问题,对抓胎机械手取胎过程中影响胎坯纵向和横向变形的主要因素进行了研究,提出了定位内撑一体的抓取方法;并结合实际工作要求,从抓胎机械手动力学参数设计角度出发,优化设计出了新型内撑抓胎机械手,利用动力学仿真分析软件ADAMS对新型机械手内撑机构工作位置的运动及动力学特性进行了仿真分析,通过有限元柔性体分析方法,对3种抓胎机械手取胎时轮胎胎坯变形量的大小及分布情况进行了对比、验证。研究结果表明:新型机械手能够实现胎坯定位、内撑取胎的功能,并且对取胎过程中胎坯存在的变形不对称和变形量大的问题均有明显改善。 相似文献
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分析了螺旋锥齿轮磨齿加工的基本原理,以AutoCAD为开发平台,利用AutoCAD内嵌的VBA编程语言,建立了基于尺寸驱动的齿坯和砂轮的实体模型,将数控螺旋锥齿轮磨齿机的各轴运动转化为砂轮和齿坯的相对位置调整,通过砂轮与齿坯之间的相减布尔运算模拟磨齿加工过程,通过仿真实例验证了仿真算法的正确性。数控螺旋锥齿轮磨齿加工仿真系统为精确生成齿轮的三维实体模型以及验证机床调整参数提供了解决方法。 相似文献
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Weiming Wang Dayong Li Jie Hu Yinghong Peng Yishun Zhang Deyuan Li 《The International Journal of Advanced Manufacturing Technology》2005,26(5-6):537-543
A computational fluid dynamics (CFD) simulation for analyzing fluid flow patterns in a plasma spray gun is presented in this study. It is coupled with a heat transfer simulation of the plasma spray gun. Based on CFD and heat transfer theory, the numerical model of the nozzle in the plasma spray gun is developed, and the coupled simulation of the flow fluid and heat transfer is carried out with the semi-implicit method for pressure-linked equations (SIMPLE) method. Local turbulence, which will lead to appearance of a static-water region, is found at the front corner of the cooling channel in the nozzle. The locations insufficiently cooled are found in the wall near the heat source and in the gasket in the rear of the nozzle. Then, cooling processes with different parameters of cooling water are analyzed. The optimal velocity and direction of cooling water, which efficiently cool the nozzle and improve the service life of the plasma jet, are obtained . 相似文献
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建立仿真模型模拟了连铸连轧过程中铝液流经铸嘴时的温度场及速度场,试验研究了铸嘴材料与铝液在不同温度(850,900,950℃)反应不同时间(2,4,6,8,10h)后的形貌和成分,分析了铸嘴堵塞的机理。结果表明:在铝液流动过程中,铸嘴在铁板固定处的温度梯度比其他区域的高;铝液流速分布不均匀导致温度分布不均匀,与铸嘴壁接触区域的铝液温度较低,容易发生挂渣;高温铝液与铸嘴材料中的SiO2发生置换反应生成Al2O3夹渣和单质硅,Al2O3的生成会增大铸嘴壁的表面粗糙度,同时会进入铝液使其黏度增大、流速变慢,不能及时冲刷掉铸嘴壁表面挂渣,使得铸嘴壁上的夹渣不断增多,最终导致铸嘴堵塞。 相似文献
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Weiming Wang Dayong Li Jie Hu Yinghong Peng Yishun Zhang Deyuan Li 《The International Journal of Advanced Manufacturing Technology》2005,26(5):537-543
A computational fluid dynamics (CFD) simulation for analyzing fluid flow patterns in a plasma spray gun is presented in this study. It is coupled with a heat transfer simulation of the plasma spray gun. Based on CFD and heat transfer theory, the numerical model of the nozzle in the plasma spray gun is developed, and the coupled simulation of the flow fluid and heat transfer is carried out with the semi-implicit method for pressure-linked equations (SIMPLE) method. Local turbulence, which will lead to appearance of a static-water region, is found at the front corner of the cooling channel in the nozzle. The locations insufficiently cooled are found in the wall near the heat source and in the gasket in the rear of the nozzle. Then, cooling processes with different parameters of cooling water are analyzed. The optimal velocity and direction of cooling water, which efficiently cool the nozzle and improve the service life of the plasma jet, are obtained . 相似文献
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在铸造凝固过程的数值模拟中,铸件/铸型间的界面传热系数是非常关键的一个参数.为提高数值模拟精度,文中采用铝合金铸件设计了金属型铸造试验,考虑了铸型厚度对结果的影响,使用特制的热电偶采集了铸件内部不同位置的温度值.以此实测的温度场数据为基础,结合数值模拟技术和界面传热系数“反问题”的求法,得到界面传热系数与时间的函数关系.结果表明:铸型厚度不同会影响铸件铸型间的热流和界面传热系数的变化规律,且界面传热系数在铸件冷却中并非常数,随着凝固过程的继续而减小.最后将所得界面传热系数用于凝固过程的温度场模拟,与试验结果进行了对比分析,得到了合理的分布,说明此界面传热系数测定方法可行. 相似文献
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《机械工程学报(英文版)》2018,(6)
During the oscillating twin?roll strip casting process, the quality of final products is directly influenced by the flow field distribution of molten metal in the pool. The variation in the flow field is caused by oscillating roller benefits, for homogeneous distribution of strip impurity, and decreasing the grain size. Thus, the quality of the strip could be improved. A numerical model was developed using the multiphase flow technology, coupled with heat transfer, fluid flow, solidification, and oscillation. Furthermore, a transient algorithm was adopted for simulating the oscillating twin?roll strip casting process of AlSi9Cu3 and 3104 aluminum alloy. This paper focuses on the flow distribution in the pool, in comparison with the traditional vertical twin?roll strip casting process, while the amplitude or frequency is chang?ing with the definite value of casting velocity, roller diameter, nozzle angle, and the strip thickness. Consequently, the conclusions were experimentally validated by oscillating twin?roll 3104 aluminum alloy strip casting. Vibrating casting technology can change the flow field in the pool by vibration, which can improve the quality of the strip core. 相似文献
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