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Cheng Lu A Kiet Tieu Zhengyi Jiang 《Journal of Materials Processing Technology》2003,140(1-3):569-575
In this paper a method to simulate the oil thickness and length of elastic deformation in the inlet zone of cold rolling has been developed. The mixed film lubrication model was adopted to describe the behavior of the lubricant and asperity deformation. The elastic Von Karman equation was used to describe the elastic deformation of strip in the inlet zone. The length and lubricant film thickness of the inlet zone can be obtained by a numerical method. Results of simulations show that the reduction, rolling speed, back tension have a significant influence on the lubricant film thickness and the inlet zone length. 相似文献
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An efficient thermal analysis for the prediction of minimum film thickness in inlet zone at high speed lubricated cold strip rolling 总被引:1,自引:0,他引:1
The main objective of this work is to develop a formula for the prediction of thermal minimum film thickness at the roll/strip contact in terms of operating parameters particularly at the elevated roll speeds. The film thickness at the exit of inlet zone and at the entry of contact zone is common. Therefore, in order to compute minimum film thickness accurately at the contact, an efficient thermohydrodynamic analysis of fully flooded inlet zone has been carried out. The effects of rolling speed, reduction ratio, material parameter and slip on minimum film thicknesses (isothermal and thermal) and maximum film temperature rise (in the inlet zone only) are rigorously investigated. The performance parameters in the lubricated domain have been evaluated for rolling speeds (up to 20.0 m/s), reduction ratios (0.05–0.20), and slip values varying up to 20%. Significant reduction in minimum film thickness (thermal) has been observed with the increase in the rolling speed and slip. Based on this study, empirical relations are developed for the prediction of minimum film thicknesses (isothermal and thermal) at the contact. A relation for evaluation of maximum film temperature rise in the inlet zone has been also developed. Authors believe that the empirical relations presented herein may be useful for designers and practicing engineers. 相似文献
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An analytical model for metal rolling in the mixed lubrication regime was developed based on Wilson and Chang‘s asperity flattening model and Von Mises homogenous deformation model.A more rigorous average Reynolds equation was used to calculate the hydrodynamic pressure.The variations of the yield stress with strain were considered in the model.An efficient iteration procedure was developed to solve the contact area.film thickness and hydrodynamic pressure.The model is more practical with fewer assumption and converges quickly.It is applicable to a wider range of rolling regimes.The calculation results using the model agree well with the literature as well as with measured data from a rolling mill. 相似文献
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热轧润滑的效果——热轧润滑技术讲座(二) 总被引:8,自引:3,他引:5
介绍了热轧润滑技术在国内外热连轧机上的应用效果,即可明显减少辊耗,降低轧制力,轧制力矩,提高作业率,因而经济效益非常明显;同时提出进一步改善热轧润滑效果需要重视的问题。 相似文献
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热轧润滑油中的添加剂及热轧润滑在我国的发展——热轧润滑技术讲座(四) 总被引:3,自引:0,他引:3
介绍了热轧润滑油中各种添加剂的成分和功能,以及对其性能的要求,同时分析了热轧润滑在中国的发展前景。 相似文献
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混合润滑轧制入口膜厚模型 总被引:3,自引:0,他引:3
运用平均流动模型求解混合润滑轧制变形区入口膜厚问题时,提出了混合因子φm,它综合了流动因子φx和接触因子φc对入口膜厚的影响,简化了轧制润滑模型,计算和实验表明,在流体润滑条件下,表面粗糙效应形膜亦有一定的影响,也即混合因子φm还适用于流体润滑轧制,且修正了未考虑表面粗糙效应而引起的不足。 相似文献
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阐述了热轧工艺润滑的机理及作用,并结合工艺润滑技术在宝钢2050mm热轧厂的开发与应用,探讨了工艺润滑对带钢表面质量及环境的影响. 相似文献
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热轧润滑机理及其出现和应用的前景—热轧润滑技术讲座(一) 总被引:20,自引:3,他引:17
介绍了板带热轧润滑的机理及作用,分析了随着轧辊材质的进步,轧制速度的提高、市场需求的不断增加,热轧润滑技术的出现和应用前景。 相似文献
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为提高可逆冷轧机的润滑效果,以天津冷轧薄板厂四辊可逆冷轧机为例,分析了其工艺润滑特点。介绍了该厂在工艺润滑装备方面采取的改进措施及取得的良好效果。 相似文献
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基于温控形变耦合工艺下轧件厚向温度分布的特点,即使轧件厚向芯表温差相等,但厚向温度梯度不同,会对金属变形产生不同的影响。通过数值模拟,研究了厚板厚向温度梯度对轧件内部金属变形的影响。对于芯表温差为300 ℃的温度场,随着冷却强度与水冷时间的不同,沿钢板厚向会形成“近表层大温度梯度区+近芯部等温区”的混合温度场。随着冷却强度的增大,水冷时间的减少,近芯部等温区厚度逐渐增加。经模拟计算,当钢板近芯部等温区厚度增加至1/2板厚时,轧件芯部应变值减少约0.015。结果表明,大冷却强度、少水冷时间的温控形变耦合工艺,会弱化轧件厚向变形渗透效果。另外,随着近芯部等温区厚度的增加,头部沿纵向金属变形不均匀性减小,表明大冷却强度、少水冷时间的温控形变耦合工艺,有利于提高轧件头部沿长度方向的金属流动均匀性。 相似文献
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最小可轧厚度是轧制理论中的一个经典问题,轧件厚度逐渐减小到接近一个极限,而不能再继续减薄。异步轧制引入了异速比的概念,轧件因上下表面摩擦力不同而产生搓轧作用,使金属更容易变形,此时是否还有最小可轧厚度需要进一步研究。实验发现,搓轧区比例是影响最小可轧厚度的关键参数,在此基础上推导了异步轧制条件下的最小可轧厚度新公式。并指出接近全搓轧时,最小可轧厚度可趋近于0;是否能达到,取决于轧制过程是否因裂纹、孔洞、褶皱等原因导致的断带而终止。 相似文献