本科毕业论文范文.doc

华北电力大学
毕业设计(论文)
题目
所在院系能源动力与机械工程学院
专业班级实验动10班
学生姓名杨
学号 11011 025
指导教师签名
审批人签字
2014 年 3 月 24 日
摘要
纯铝具有良好的物理力学性能:易加工、耐久性高、适用范围广、装饰效果好、花色丰富。由于铝的优秀性能,铝越来越多的用于机械制造行业. 随之而来的是对铝焊接的要求也越来越高.
目前国外MIG焊铝的技术工艺日趋成熟, 主要用于全焊接游轮, 火车及汽车箱体, 摩托车架, 压力容器, 工作平台, 飞机等。在飞机、汽车和机车车辆等制造业中,为了减轻运载工具的自重,提高运载能力,越来越多地采用轻金属合金与薄壁型轻量化结构。尤其在飞机蒙皮、筋板等制造中,采用焊接代替传统的铆接工艺,减重效果显著。然而由于铝特性及T型接头结构特点,无论传统焊接还是先进的激光焊接都遇到了焊缝气孔、裂纹、变形等依靠单独焊接方式难以解决的问题。
本文将主要研究焊接速度、焊接电流以及频率的变化对焊接外观造成的影响,从而找到最合适的焊接参数。本文包括三组实验,分别对焊接速度、焊接电流以及频率的影响作了详细的分析,比较各个参数对焊缝的影响,最终通过实验优化了纯铝MIG焊的焊接工艺。实验证明:,焊接速度为35cm/min,焊接电流为77 A, Hz时,为较佳工艺。
关键词:铝;熔化极氩弧焊;焊接工艺
Abstract
Has good physical and mechanical properties of pure aluminum: easy processing, high durability for a wide range of decorative effect, and rich colors. Due to the excellent performance of aluminum, aluminum, more and more used in the machinery manufacturing industry, followed by increasingly high requirements for aluminum welding.
Foreign MIG welding aluminum technology matures, mainly for the all-welded cruise ships, trains and car box, motorcycle frames, pressure vessels, work platform, aircraft. In the manufacturing of airplanes, cars and rolling stock, in order to reduce the weight of the means of delivery, to improve the carrying capacity, more and more lightweight construction of light metal alloys and thin-walled type. Especially in the manufacturing of aircraft skin, ribs, using welding instead of riveting, significant weight loss. However, due to the aluminum features and T-joint structural characteristics, regardless of traditional welding or laser welding encountered weld pores, cracks, deformation, etc. rely on a separate welding difficult problem to solve.
This article will mainly study the welding speed, welding current and frequency changes caused by the welding appearance in order to find the most suitable welding parameters. In this paper a total of three sets of experiments, made ​​a detailed analysis of the change of welding spee