文档介绍：钛合金激光焊接工艺研究及激光穿透焊温度场数值模拟
摘要
钛及钛合金因其比强度大和优良的耐酸腐蚀性能,在各行各业中得到越来越广泛的应用。激光焊接由于具有能量集中、焊缝成形好、操作简单、易于监测等优点,非常适合焊接钛合金材料。
论文通过激光焊接试验表明钛合金激光焊接的主要缺陷是气孔,空气中的氧气、氮气和工件表面的水分是造成气孔的主要原因。钛合金激光焊接焊缝强度、硬度提高, 塑性、弯曲性能下降。~1800W,~。
激光穿透焊接过程包含着一系列复杂的物理、化学反应现象,表现出快速、复杂、多维、多参数影响等特点。激光与材料相互作用时,因聚焦激光束功率密度高(通常高达10。W/cm2以上),被焊材料在极短时间内熔化、汽化乃至蒸发,从而形成小孔, 并出现激光诱导的等离子体。在激光焊接过程中,光致等离子体、小孔以及熔池的行为决定了焊缝成形以及焊接质量。对激光焊接的模拟尽管前人已经作了大量的研究, 但是对激光穿透焊接三维温度场的实时再现仍存在一定的局限。目前,虽然ANSYS(一种大型有限元软件)正在成为有限元模拟领域研究的热点,但国内外还未见将其应用在激光焊接过程数值模拟的相关报道。
论文探讨了基于ANSYS软件进行激光穿透焊接三维温度场数值模拟的若干关键问题。论文采用球状热源和柱状热源相结合的双热源模型,用APDL语言开发的ANSYS 计算程序,能有效地对激光穿透焊接过程三维温度场变化情况进行模拟。论文还针对使用ANSYS软件要求较高的特点,采用面向对象程序设计的方法进行二次开发,在VC++。这样,通过其友好的人机界面,激光焊接专家只需输入激光穿透焊接工艺参数即可自动调用ANSYS模块进行后台计算,而勿需专门学****有限元理论和ANSYS软件,方便了用户的使用。
关键词:钛合金激光弹接激光穿逸焊三维温度场数宿模拟
ABSTRACT
With the advantages of high strength—to—weight rmio,excellent corrosions resistance,
titanium and titanium alloy have been applied more and more widely in many
laser welding is suitable for the titanium and titanium alloy because of its lligh power
density,good welding performance,and easy inspection.
Based on experiments of titanium laser welding,the result shows pores are nqon
defect in the weld for laser welding of titanium 02,N2 in the air and the H20
absorbed On the surface of the work piece are the main resource of these
titanium weld、vim laser welding has higher strength and hardness,lower ductility than
those of base the laser welding of titanium alloy witll
power 1600~1800W and welding speed - were mended in the thesis.
The process of laser full—ration welding includes a serial of physical and chemical interaction of high power laser beam wit}l the target materials is
plex,muti—dimensional and muff-parameter power density of the order of
1 06W/cm2 typically used in deep ration welding,the irradiated sur