【作者】 孙卫刚；

【导师】 张治民；

【作者基本信息】 中北大学 ， 材料加工工程， 2008， 硕士

【摘要】 本文针对钢制轮辋存在的超重和综合力学性能不高的问题,进行了7A04铝合金轮辋成形工艺的研究,分析了变形次数对7A04铝合金性能的影响。首先,应用有限元数值模拟技术,分析了7A04铝合金轮辋反挤压成形过程以及变形速度、摩擦系数等工艺参数对成形过程的影响。数值模拟表明:7A04铝合金在460℃和10mm/s的条件下进行挤压时具有很好的流动性和低的变形抗力;在其它条件相同的情况下,摩擦系数的增加使变形的不均匀程度增大。在数值模拟的基础上,提出了一种降低成形力、提高产品质量的铝合金轮辋成形方法,采用空心坯料挤压、逐次成形,显著降低了成形力,在6300KN压力机上实现了20英寸轮辋的成形;采用大变形、等温多次成形,提高了产品的综合力学性能,与钢制轮辋相比,抗拉强度与屈服强度由400Mpa和235Mpa提高至570Mpa和510Mpa左右。实践应用表明:与钢制轮辋相比减重约55.6%,有效的实现了减重与力学性能的提高,达到了预期效果。分析了变形次数对7A04铝合金力学性能与微观组织的影响规律,确定了7A04铝合金适合的变形次数。实验表明:在实验范围内,随着变形次数的增加,强度逐渐升高,当变形次数为四次时,达到最大,继续增加变形次数强度降低。因此采用四次变形可达到最大的极限强度和屈服强度,为7A04铝合金的塑性加工提供了理论依据。在此基础上,针对现工艺存在的材料利用率低的问题进一步优化,为该产品的大批量生产做好准备。更多还原

【Abstract】 This paper was directed against the overweight and the lower comprehensive mechanical properties of steeliness wheel felloe, studied the forming process of 7A04 aluminum alloy wheel felloe, and analyzed the effects of deformation times on properties of 7A04 aluminum alloy wheel felloe.Firstly, using numerical simulation of finite element, the backward extrusion process of 7A04 aluminum alloy and effects of deformation speed and friction coefficient on forming were analyzed. The numerical simulation showed that the aluminum alloy had good flow and low extrusion pressure under the conditions of 460℃and 10mm/s; In the same conditions, with the friction coefficient increasing, the inhomogeneous deformation increased .On the basis of numerical simulation, a forming method of 7A04 aluminum alloy which reduced the forming pressure and improved the product quality was presented. This method used hollow blank extrusion to form gradually, obviously reduced the forming pressure, and realized 20 inch wheel felloe formation on the 6300KN press; also it used the big deformation and isothermal deformation for many times, and improved the product comprehensive mechanical properties. Comparing with the steeliness wheel felloe, the tensile strength and the yield strength were improved by 400Mpa and 235Mpa to about 570Mpa and 510Mpa. The practical application showed that comparing with the steeliness wheel felloe, the weight reduced approximately 55.6%. This method realized effectively the reduction and the improvement of mechanical properties, and achieved the expectation goal..The effects of deformation times on mechanical properties and microstructure of 7A04 aluminum alloy were analyzed, and the appropriate deformation times of 7A04 aluminum alloy was determined. The experiment showed that in the scope of experiment, along with the increasing of deformation times , the intensity improved gradually, when the deformation times was four , the intensity achieved biggest, continued to increase the deformation times intensity to reduce. Therefore using four deformation times was possible to achieve the biggest tensile strength and yield strength, this provided basical theory for plastic processing of aluminum alloy. Based on this analysis, aimed at the problem of the lower of material utilization for present process, optimized the process, and prepared for this product in enormous quantities.更多还原