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题名: 长焊缝激光拼焊焊缝碾压预成型技术研究
其他题名: Preprocessing Technology to Weld Seam for Tailored Blank Laser Welding
作者: 王军义
导师: 徐志刚
分类号: TG665
关键词: 激光拼焊 ; 焊缝碾压预成型 ; 塑性变形 ; Kriging模型
索取号: TG665/W33/2010
学位专业: 计算机应用技术
学位类别: 硕士
答辩日期: 2010-06-03
授予单位: 中国科学院沈阳自动化研究所
学位授予地点: 中国科学院沈阳自动化研究所
作者部门: 装备制造技术研究室
中文摘要: 激光焊接作为激光加工的重要组成部分,其应用范围几乎涵盖了所有的焊接领域,其中的激光拼焊技术更是在汽车制造领域中处于举足轻重的地位,激光拼焊是采用激光作为能源,将若干不同材质、不同厚度、不同涂层的钢材或铝材进行自动焊接而形成一块整体板材,以满足零部件对材料性能的不同要求。焊接质量的保证是激光拼焊最关键的技术难点,引起激光焊接缺陷的因素很多,主要有光束质量、母材性能、焊接工艺参数、焊接工件参数及保护气体等。焊接工件参数主要是指焊接前两被焊板材边缘的配合精度,由于采用激光焊接时激光能量集中,光束直径很小,如果两被焊板材边缘配合精度不高使焊缝间间隙过大,激光将无功透过间隙而影响焊接质量。由于普通剪板机的剪切误差使剪切的板材边缘不可能精确平直,另外还有焊机本身的定位对中误差等因素使两板装配后的配合精度很难达到焊接要求。这就要求焊接前对板材边缘进行预处理以使其达到焊接要求。 本文提出了长焊缝激光拼焊焊缝碾压预成型技术,即通过碾压轮对被焊板材厚板焊缝边缘进行碾压使其发生向焊缝方向的塑性变形来填补两板间的间隙以降低激光拼焊对板材边缘直线度及焊机定位对中精度的要求,从而提高激光拼焊的质量和速度。文章主要针对激光拼焊焊缝碾压预成型技术中需要解决的几个关键问题展开研究。 首先,通过建立数学模型分析了板材在碾压过程中的受力模型,给出了板材顺利进入碾压和进行碾压需要满足的条件;其次,通过利用数值分析模拟和实验相结合的方法分析了两板间力的作用规律,给出了板材在碾压过程中不发生窜动需要满足的力学条件;再次,通过利用有限元计算和实验验证的方法分析了影响板材塑性变形规律、板材发生一定塑性变形所需要碾压力的各种因素及其影响规律,这些影响因素包括碾压轮的几何参数、碾压工艺参数、板材的厚度及同一板材的不同位置;最后利用Kriging近似优化模型对碾压轮的几何参数即碾压轮的直径、宽度和边缘形状进行了最优化设计。 依据本文理论所搭建的长焊缝激光拼焊焊缝碾压预成型试验台的试验结果显示焊缝碾压预成型技术能有效降低激光拼焊对板材边缘质量及焊机定位对中精度的要求,有效提高激光拼焊焊接质量和焊接速度。
英文摘要: Tailored blank laser welding is one of the most famous laser joining application which plays an important role in the advanced welding. Laser tailored blank welding is widely used in automotive industry, shipbuilding, aerospace industry, etc. The most critical technology problem of the laser welding is guaranteing the welded qulity. The factor causes the defect of the laser welding mainly is the qulity of laser beam, characteristic of blank, welding procedure, assembly accuracy of the blank will be welded and so on. Assembly accuracy of the blank will be welded mainly is the width of the gap between two blanks. If the width of the gap is lager than 0.08mm, the energy of the laser will traverse the gap without melting the sheets and the welding quality will lower also.so the problem arise that the sheets have to be located edge to edge and the width of gap between them before welding must be only 0.05 to 0.08mm. This means that each of the two sheets may deviate only 0.04mm from straight. With the extended welds which occur in laser welding blank, it is extremely laborious to obtain such a narrow width of gap along the entire length of the located edges of the sheets to be welded. Plastic and precise roller-preform of seam process to reduce the width of the gap between the steel sheets will be welded is presented. Plastic and precise roller-preform of seam is one of the most effective methods to reduce nonlinear positioning error which is the most difficult problem in tailored blank laser welding for the long seam. The width of the gap between the sheets is reduced by plastically deforming one of the thicker sheets causes material to flow mainly in the direction of the weld seam by roller forming ahead of welding zone.  The mathematical model of precise roller-preform of seam is built to study the force model in the processing of roller forming. The finite element analysis is used to study the material flows rule. A new optimization method which covers experimental optimization technique, Kriging model, finite element method and other theory for the mechanism of precise roller-preform is firstly developed based on Kriging model to select optimum design variables.  A precise roller-preform test table is developed based on these theories, and the experiment results indicate that precise roller-preform can improve the welding quality.
语种: 中文
产权排序: 1
内容类型: 学位论文
URI标识: http://ir.sia.cn/handle/173321/9309
Appears in Collections:装备制造技术研究室_学位论文

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Recommended Citation:
王军义.长焊缝激光拼焊焊缝碾压预成型技术研究.[硕士学位论文].中国科学院沈阳自动化研究所.2010
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