摘要窄间隙激光多道焊焊技术整合了激光焊和窄间隙焊的优点，具有焊接热输入 小、热影响区小和焊后工件变形小等优点，近年来受到越来越多研究者的重视。 本文以 CCS-B 级船用钢为试验材料，采用窄间隙激光多道焊的方法，研究了激 光功率、焊接速度、送丝速度和离焦量等工艺参数对焊缝成形的影响规律，并选 用优化的焊接工艺焊接了 50mm 的 Q345D 低合金高强钢。焊后观察并分析了接 头的宏观和微观组织。81341

试验结果表明：(1)在平板堆焊条件下，激光功率的增加会使焊缝的熔深增 加，熔宽增加幅度较小；离焦量的增加会使焊缝的熔深显著减小，而使焊缝熔宽 增加；(2)在窄间隙激光填丝焊条件下，激光功率的增加会使焊缝熔深增加，而 熔宽在激光功率为 3。7kW 时最大；离焦量的增加会使焊缝熔深减小，而熔宽基 本不变 ； (3) 当 激 光功 率 P=5。0~5。7kW ， 焊 接 速 度 V=0。6m/min ，送丝速度 Vf=5。9m/min，离焦量 f=+25~+46mm 时，成功焊接了 50mm 厚的 Q345D 低合金 高强钢，共焊了 17 道，包括一道激光自熔焊和 16 道激光填丝焊；(4)通过对窄 间隙接头组织的观察分析可知：侧壁融合良好，层间过渡均匀，受二次热循环作 用的区域，其组织得到细化，成分更加均匀，接头性能良好。

毕业论文关键词：厚板，窄间隙，激光填丝焊，焊接工艺

Abstract

Narrow gap laser multi-pass welding technology integrates the advantages of laser welding and narrow gap welding including small heat input and welding deformation and HAZ。 More and more researchers attention to it in recent years。 Based on CCS - B Marine steel as the experimental material, adopt the method of narrow gap laser multi-pass welding to study the process parameters such as the laser power, welding speed and wire feed speed and defocusing amount, etc, to understand its influence on the appearance of welding joint,and use the optimized parameters to weld the 50 mm Q345D high-strength low alloy steel。

The experimental results showed that：（1）Under the condition of flat welding,

the increase of laser power will increase the weld penetration, weld width increases slightly, the increased of defocusing amount can make weld penetration decreases rapidly, and make the weld width increase。（2）Under the condition of narrow gap

laser wire filling welding, the increase of laser power, will increase the weld penetration, and the fusion width at 3。7 kW has a maximum, the increased of defocusing amount will reduce weld penetration, and the weld width basically  remain

unchanged（。  3）When the laser power P = 5。0 ~ 5。7 kW, welding speed V = 0。6 m/min,

Vf = 5。9 m/min, wire feeding speed from coke f = + 25 ~ +46 mm, successdev in welding the 50 mm thick Q345D high-strength low alloy steel, welding 17 layers, including a layer of laser welding and 16 layer wire filling welding。(4) Through the

analysis and observation of the narrow gap joint organization，sidewall fusion and the

uniform transition between the layers is well, the area which affected by thermal cycle twice, its organization are refined, more uniform composition, joint performance is well。

Keywords: thick plate; narrow gap; high-strength steel; laser filler wire welding; welding process

目录

第一章 绪论 1

1。1 课题研究背景及意义 1

1。2 厚板窄间隙焊接技术研究现状 2

1。2。1  窄间隙埋弧焊技术 2

1。2。2  窄间隙熔化极气体保焊技术 3

1。2。3 窄间隙钨极氩弧焊技术