【作者】 焦传江；

【导师】 陈铠；

【作者基本信息】 北京工业大学 ， 光学工程， 2009， 硕士

【摘要】 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。然而由于铝合金特性及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。本文采用激光-电弧两侧同步焊接方法成功焊接了3mm厚铝合金T型接头,既发挥了两种热源的优势,又弥补了各自的不足。首先,根据激光-电弧两侧同步焊接试验要求和T型接头特点,设计与优化了定位装置、电弧焊枪及工装夹具,为工艺研究提供了装备条件。其次,研究了铝合金激光-电弧两侧同步立板横焊的工艺参数对焊缝成形的影响,得出一组焊缝成形好的参数范围,为T型接头焊接试验打下基础。结果表明:激光-电弧两侧同步焊接关键是实现两侧熔池相互贯通。当两侧能量较匹配,两熔池完全贯通、熔为一体、两侧熔宽相差较小时,激光与电弧相互作用强,焊接过程稳定,焊缝成形好。最后,研究了6061铝合金T型接头激光-电弧两侧同步焊接工艺参数、接头形式对焊缝成形的影响,并对焊接头显微组织、力学性能进行了考察与分析。结果表明:采用激光-电弧两侧同步焊接在合适的工艺参数下T型接头焊缝成形好,两侧焊缝组织相似且以等轴晶为主,过度均匀。十字架焊接接头的抗拉伸强度达247.7MPa,断于母材;弯曲角度超过15°,裂纹呈锯齿状。研究成果有助于进一步了解激光-电弧两侧同步焊接相互作用,有助于进一步降低焊缝气孔、变形等焊接缺陷,提高焊接过程稳定性和能量利用率,从而提高我国高强铝合金焊接技术在航空航天、快速列车、高速轮船及汽车等制造行业的应用。更多还原

【Abstract】 Today, light metal alloys and thin-walled lightweight structure are increasingly used in manufacturing industries such as aircraft, automobile and rolling stock in order to reduce vehicle weight and improve carrying capacity. It is prominent to reduce weight that using welding crafts replace traditional rivet bond especially in the manufacturing of the aircraft skin, panel, etc... However, due to the properties of aluminum alloy and the structural characteristics of T-joint, whether traditional TIG welding or advanced laser welding has to face with some problems in formation of weld, such as pores, cracks, deformation, which are difficult to solve by single way. In this paper, the fillet weld for T-joint of 3.0 mm thick 6061 aluminum alloy has been completed through Laser–TIG Both-Side Synchronization Welding (LTBSW), which provides many advantages which are not found in either.First of all, the positioning device, arc torch and fixture which offer the equipment condition for craft investigation have been designed and optimized according to requirements of LTBLW experiments and structural characteristics of T-joint.In addition, we have studied with the LTBSW horizontal welding in vertical board on different welding parameters which effect formation of weld, obtained good parameter range, and lay the groundwork for welding of T-joint. The results show that the key of LTBSW is to realize the linking up of the molten pool on both sides each other in T-joint. When the laser and arc energies on both sides are properly matched, both molten pools can be integrated, and the interaction of laser-arc is strengthened, such as melting into organic whole, smaller differences on welding width. In this case, a stable welding process and good formations of the welds are achieved.Finally, the effects of weld parameters for 6061 aluminum alloy of T-joint and forms of weld joints on the welding seam have been studied. Then, microstructure and mechanical properties of weld have been studied and analyzed as well. The results show that right process parameters of LTBSW in T-joint can complete good formations of weld which has similar organizations on both sides and has properties of grain-based and transitional uniform. Tensile strength for welding joints which has been broken in the parent material is up to 247.7Mpa. Bending angle has reached more than 15°and the crackle has taken the form of saw tooth.The research results can help to understand the interaction between laser and arc hybrid processing, reduce porosity deformation in T-joint, as well as improve the stability of weld process and energy utilization. This research helps to improve welding technology of the high-strength aluminum alloy and applications in the fields of Aero-Space, fast trains, ships and automobiles, etc...更多还原