【作者】 徐轶；

【导师】 刘全坤；

【作者基本信息】 合肥工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 矩形钢管是钢结构的最佳立柱材料之一,在建筑、化工、电站等各行各业都有广泛的应用。但是受理论基础和研究方法的限制,目前矩形钢管拉拔工艺仍然采用以经验为主的试验法制定,产品质量难以保证。有限元模拟技术可以获得金属变形更微观全面的认识,已经日益成为塑性成形研究中的有力工具。 本文以130×50×3.5mm矩形管为例,对矩形管拉拔成形过程进行研究。首先,通过分析矩形管成形过程的变形特征,以及成形方法和工艺参数对成形的影响,确定采用辊模拉拔与短芯棒拉拔相结合的两道次拉拔工艺方案。在此基础上,建立有限元模型并对矩形管拉拔成形过程进行三维有限元模拟,得到应力应变的分布状况和金属的流动规律。 针对矩形管拉拔成形中出现的不足,本文从两个方面对矩形管拉拔成形过程进行优化。一方面,引入流函数法建立拉拔模的模腔曲面方程,对传统的锥形模模腔进行优化,设计出“流线型”拉拔模。通过对“流线型”拉拔进行有限元模拟,并和传统的“直线型”拉拔对比后发现,“流线型”拉拔改善了金属的流动状态,在拉拔稳定性、能量消耗及模具磨损上均优于“直线型”拉拔。另一方面,采用正交试验和数值模拟相结合的方法对拉拔成形的工艺参数进行优化,分析了摩擦系数、拉拔速度、入口锥角、定径带长度、水平辊孔型半径和水平辊间距对矩形管拉拔成形的影响。采用极差分析的手段,判断指标(总应变能、周向残余应力)对各工艺参数的敏感程度,得到最佳的工艺参数组合方案。 本文的研究结论对矩形钢管生产有实际指导意义。更多还原

【Abstract】 Rectangular steel tube is one of the best support column among the steel structure, which is widely applied in various industries, such as architecture, chemical industry, power plants and so on. However, due to the limitation of theory basis and research methods, currently the rectangular steel tube drawing process is still constituted by experience-oriented experiment, which causes the quality of products instable. The FE simulation is becoming a powerful tool of mental plastic forming, with which people can get a complete and micro knowledge of this field.Taking the rectangular tube with the specification of 130×50×3.5mm as an example, this thesis has made a study on the rectangular tubes drawing process. Firstly, by means of analyzing forming character, forming ways and the effect of processing parameters to rectangular tubes drawing, two-time drawing process, combining with roll-drawing and short mandrel drawing, was confirmed to employ. On this basis, the three-dimensional FE model was established and the rectangular tubes drawing process was simulated. Simulation results show the distributions of stresses and strains and the rule of metal flows.Aiming at the deficiency of rectangular tube drawing process, the forming process was optimized from two aspects. On one hand, author introduced stream function to establish the surface function of drawing die , optimized the traditional cone die and designed streamline die. Through the FE simulation of streamline drawing and the comparison with traditionally drawing, it is obviously that streamline drawing improves the flowing performance of metals, and moreover, the drawing stability, energy consumption and die abrasion are superior to traditionally drawing. On the other hand, adopting the method combined of orthogonal experimental design and FE simulation to optimize the processing parameters, the effect of six parameters to the rectangular tube drawing process was analysed, including friction factor, drawing speed, cone angle, length of calibtrating strap, radius and space of roll die. Employing range analysis, the sensitivity of index arm(total strain energy, residual stress)on processing parameters was estimated and finally gained the best combination scheme of processing parameters.The research conclusions of the thesis have a practical and instructional significance on rectangular steel tubes production.更多还原