大型复杂薄壁铝合金空心型材挤压成形工艺_孟佳杰.pdf

精 密 成 形 工 程 第 15 卷 第 4 期 58 JOURNAL OF NETSHAPE FORMING ENGINEERING 2023 年 4 月 收稿日期：20221031 Received：2022-10-31 基金项目：上海市青年科技启明星项目（21QB1404500）；上海航天科技创新基金（SAST2020044）Fund：Shanghai Science and Technology Development Funds(21QB1404500);Shanghai Aerospace Science and Technology Innovation Fund(SAST2020-044)作者简介：孟佳杰（1994），男，硕士，助理工程师，主要研究方向为金属材料塑性成形。Biography：MENG Jia-jie(1994-),Male,Master,Assistant engineer,Research focus:plastic forming of metals.通讯作者：徐琅（1988），男，博士，高级工程师，主要研究方向为金属材料塑性成形。Corresponding author：XU Lang(1988-),Male,Doctor,Senior engineer,Research focus:plastic forming of metals.引文格式：孟佳杰,徐琅,李国钧,等.大型复杂薄壁铝合金空心型材挤压成形工艺J.精密成形工程,2023,15(4):58-66.MENG Jia-jie,XU Lang,LI Guo-jun,et al.Extrusion Forming Process of Large and Complex Thin-walled Aluminum Alloy Hollow ProfileJ.Journal of Netshape Forming Engineering,2023,15(4):58-66.大型复杂薄壁铝合金空心型材挤压成形工艺 孟佳杰1,2，徐琅1,2，李国钧1,2，徐晨1,2，欧庆峰3，王玉刚3（1.上海航天精密机械研究所，上海 201600；2.上海神剑精密机械科技有限公司，上海 201600；3.山东兖矿轻合金有限公司，山东 邹城 273513）摘要：目的目的 解决大型复杂薄壁铝合金空心型材挤压过程中材料流速均匀性控制难，以及模具局部应力集中导致模具寿命低、挤压型材尺寸稳定性差的问题。方法方法 采用有限元模拟方法对此类典型型材挤压过程进行仿真分析，根据仿真结果中型材出口材料流速分布情况，通过调控不同部位材料流入量及材料流动阻力，并以型材出口流速差和流速均方差（SDV）作为衡量挤压过程中材料流速均匀性的指标，逐步迭代优化模具结构以提高材料流动均匀性；根据仿真结果中挤压模具应力分布情况，以模具最高应力作为衡量模具强度的指标，逐步迭代优化模具结构以减小模具应力。结果结果 通过迭代仿真依次优化模具工作带长度、分流孔尺寸、阻流块高度等参数，最终型材出口流速差由 25.07 mm/s 降至 2.72 mm/s，流速均方差由 9.84 mm/s 降至 0.72 mm/s；通过迭代仿真优化焊合角度，最终模具最高应力由 945 MPa 降至 863 MPa。采用基于有限元仿真优化结构的挤压模具成功制备了合格的铝合金型材样件，挤压试验结果与数值模拟结果吻合。结论结论 通过优化模具工作带长度、分流孔尺寸及阻流块高度，调控不同部位材料流入量及材料流动阻力，能够有效解决大型复杂薄壁铝合金空心型材挤压流速均匀性差的问题；通过优化模具焊合角度，能够显著降低模具局部应力集中。关键词：大型复杂薄壁铝合金空心型材；数值模拟；流速均方差；模具应力；模具结构优化 DOI：10.3969/j.issn.1674-6457.2023.04.007 中图分类号：TG376.2 文献标识码：A 文章编号：1674-6457(2023)04-0058-09 Extrusion Forming Process of Large and Complex Thin-walled Aluminum Alloy Hollow Profile MENG Jia-jie1,2,XU Lang1,2,LI Guo-jun1,2,XU Chen1,2,OU Qing-feng3,WANG Yu-gang3(1.Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China;2.Shanghai Shenjian Precision Machinery Tech-nology Co.,Ltd.,Shanghai 201600,China;3.Shandong Yankuang Light Alloy Co.,Ltd.,Shandong Zoucheng 273513,China)ABSTRACT:The work aims to solve the problem that it is difficult to control the material velocity uniformity during the extru-sion process of large and complex thin-walled aluminum alloy hollow profiles,and the local stress concentration of the die leads 第 15 卷 第 4 期 孟佳杰，等：大型复杂薄壁铝合金空心型材挤压成形工艺 59 to short die life and poor dimensional stability of the extruded profile.The extrusion process of this profile was simulated and analyzed by finite element simulation.According to the material velocity distribution of the extruded profile in the simulation results,by adjusting the material inflow amount and material flow resistance in different parts,and the velocity difference of the extruded profile and the speed deviation(SDV)were used as indexes to measure the velocity uniformity of the material,and then the die structure was optimized gradually to improve the material flow uniformity.According to the stress distribution of the extrusion die in the simulation results,the maximum stress of the die was used as an index to measure the strength of the die,and then the die structure was optimized gradually to reduce the stress of the die.By optimizing parameters such as length of working belt,size of porthole and height of blocking block,the velocity difference of the extruded profile was reduced from 25.07 mm/s to 2.72 mm/s,the SDV was reduced from 9.84 mm/s to 0.72 mm/s.By optimizing the welding angle by simulation,the maximum stress of the die was reduced from 945 MPa to 863 MPa.The aluminum alloy profiles with qualified dimensional accuracy and mechanical properties were successfully prepared with the extrusion die with optimized structure,and the extru-sion experimental results were in good agreement with the numerical simulation results.By optimizing the length of working belt,size of porthole and height of blocking block,and adjusting the material inflow amount and material flow resistance in dif-ferent parts,the non-uniform material flow velocity of large and complex thin-walled aluminum alloy hollow profiles can be ef-fectively solved.By optimizing the welding angle of the die,the local stress concentration of the die can be significantly reduced.KEY WORDS:large and complex thin-walled aluminum alloy hollow profile;numerical simulation;speed deviation;die stress;die structure optimization 大型复杂薄壁铝合金空心型材在航空航天领域有着广泛的应用，其多采用等截面箱（筒）型形式，结构上主要由外层蒙皮和内层筋条组成。这类构件目前主要采用对蒙皮和筋条分别塑性成形，再焊接为一体的制造方案，制造工艺流程繁琐，加之焊接前后对蒙皮和筋条都需进行校形及修配，焊接还需定制专用工装以保证焊接过程不发生明显变形，致使此类构件制造周期长、成本高。挤压成形可生产具有特定断面特征的型材，具有成形精度好、生产效率高、成本低等优势1-3。为提高此类型构件生产效率，降低制造成本，文中以典型大型复杂薄壁铝合金空心型材构件为对象，采用挤压成形的方法对其进行整体成形。但此类构件断面外接圆直径一般在 200 mm 以上，属于大断面/超大断面型材，研究表明，此类大断面型材挤压成形主要存在两个方面的难点：一方面，此类大断面型材模具设计需综合考虑如型材最小壁厚、是否存在悬臂、是否具有空腔等问题，模具设计难度高4-5，不合理的模具设计极易导致挤压过程中型材断面各部位材料流速不均匀，致使型材出现扭拧、波浪、起皱等缺陷，甚至无法成形；另一方面，由于热挤压过程中模具长时间承受高温、高压、高摩擦及反复的循环应力作用6，工况极其恶劣，加之模具结构复杂，模具局部应力集中区极易产生塑性变形，影响挤压型材的尺寸稳定性，甚至导致模具开裂失效，因此，模具设计是决定此类型材挤压产品质量的关键。对于此类构件模具的设计，需要在保证金属流速精