铝合金异形复杂截面构件成形研究

发布时间：2018-02-13 17:13

本文关键词： 铝合金复杂截面中空分流终成形载荷变形均匀性　出处：《中北大学》2015年硕士论文　论文类型：学位论文

【摘要】：铝合金异形复杂截面构件的几何形状复杂，中心为圆形凸台，凸台周围有较高的加强筋，整体成形十分困难。由于需承受较大的冲击载荷，构件要求有较高的力学性能。如采用形状规则的圆柱体毛坯进行直接成形，就会产生边缘部充不满，，筋部折叠等严重的质量问题，同时有终成形载荷过大、局部变形不均匀等缺陷。对于此类复杂截面构件的整体成形，为避免上述缺陷，需要进行预成形设计的改进，从而满足构件较高的力学性能要求。本课题采用有限元模拟和实验相结合的方法，研究铝合金异形复杂截面构件的整体成形过程中金属流动规律，对成形过程中构件应力、应变、流动速度及载荷等物理场量进行分析，研究了构件在终成形时成形载荷较高、变形不均匀的原因，分析了高筋部分折叠、边缘部分充不满等缺陷的形成机理。针对上述问题，根据分流成形原理，提出铝合金异形复杂截面构件预成形改进设计方案：采用中空的预成形坯料，使金属材料在成形过程中实现分流成形，降低材料充填模腔的阻力及终成形载荷，提高材料变形均匀性，避免了成形过程中折叠及充不满缺陷。研究了预成形坯料关键结构参数：中空凹面方向、坯料凹面的半径R与坯料半径R0之比（R/R0）、边缘部分与中空凹面的高度差ΔH和原方案坯料高度H之比（ΔH/H）对终成形应力、应变及载荷的影响规律，得出合理的预成形坯料关键结构参数，使终成形载荷相比原方案降低了30%，改进后的成形方案比原方案金属变形更加均匀。采用改进后的成形方案进行实验试制，成功生产出合格工件。在产品不同部位上取试样，进行冲击韧性、金相组织以及力学性能的对比，证明改进后的成形方案各项指标较原方案有较大提高，验证了此工艺方案的合理性。
[Abstract]:The geometric shape of the aluminum alloy special-shaped and complex cross-section members is complex, the center is a circular convex table, and there are high reinforcement bars around the convex table, so it is very difficult to form the whole. If a cylindrical blank with regular shape is used for direct forming, serious quality problems such as filling of edges, folding of tendons, and excessive final forming load will occur. In order to avoid the defects mentioned above, it is necessary to improve the preforming design to meet the higher mechanical performance requirements of this kind of complex cross-section members. In this paper, the method of finite element simulation and experiment is used to study the metal flow law in the forming process of the aluminum alloy special-shaped and complex cross-section members, and the stress and strain of the members during the forming process are analyzed. Based on the analysis of physical field such as flow velocity and load, the causes of high forming load and uneven deformation are studied, and the forming mechanism of the defects such as the folding of the high reinforcement and the dissatisfaction of the edge are analyzed. In view of the above problems, according to the principle of shunt forming, an improved design scheme of aluminum alloy special-shaped complex cross-section member preforming is put forward: the hollow preformed blank is used to make metal material realize shunt forming in the forming process. The resistance and final forming load of material filling die cavity are reduced, and the uniformity of material deformation is improved, and the folding and filling defects are avoided in the forming process. The key structural parameters of preformed billet, such as the hollow concave direction, the ratio of the radius R of the blank concave to the radius R0 of the blank, the height difference between the edge part and the hollow surface, and the ratio of the height of the original blank (螖 H / H) to the final forming stress, are studied. According to the influence of strain and load, the key structural parameters of preformed billet are obtained, the final forming load is reduced by 30% compared with the original scheme, and the improved forming scheme is more uniform than that of the original scheme. The qualified workpiece was successfully produced by using the improved forming scheme. Samples were taken from different parts of the product, and the impact toughness, metallographic structure and mechanical properties were compared. It is proved that each index of the improved forming scheme is much higher than that of the original scheme, and the rationality of the process scheme is verified.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG306

【参考文献】