摘要：激光复合焊接技术是近几年新兴的特种制造方法，处于起步的状态。它因焊接效率高、焊接稳定性强等优点逐渐被研究人员青睐。而高氮奥氏体不锈钢因其成分的特殊性，在通常的焊接方法下，焊接接头易产生缺陷。因此，对高氮奥氏体不锈钢采用激光复合焊接方法是一种新的思路。在激光复合焊接模拟中，研究和建立与实际焊接情况一致的热源数学模型、分析复合焊接过程的温度及应力变化规律一直是研究人员不断追求的目标。

本课题对高氮钢激光复合热源焊接的焊接过程进行仿真模拟。首先根据实际焊接情况下的熔池形貌对热源模型进行选择和修正，最后确定采用曲线-峰值递减锥体热源+峰值递增柱状热源的复合式热源模型进行仿真模拟。最终得出结论：修正后的热源模型能基本符合实际情况。由此确立了正确的热源模型。

在此热源模型的基础上进行温度场和应力场的模拟计算，结果表明该模型不仅能较好的拟合熔宽和熔深，还能较好地展示熔池的移动过程。同时，应力模拟结果也能满足实际焊接规律，可以为激光复合焊接工艺参数的设定及优化提供理论指导。

关键词 复合热源 激光焊 数值模拟

毕业设计说明书外文摘要

Title Numerical Simulation of Hybrid Laser Arc Welding of Stainless Steel

Abstract：Hybrid laser arc welding is a new type of special manufacturing technology, which is in the initial stage. Due to the high welding efficiency, welding stability and other advantages, more and more scholars have studied it. In the conventional welding method, the welding joints of the high nitrogen steel may produce welding defects easily because of its particularity. Therefore, the use of hybrid laser arc welding is a new idea. In the simulation of hybrid laser welding, the scholars try to study and establish the mathematical model of the heat source which is consistent with the actual welding, and analyze the temperature and stress changes during the welding process.

In this paper, the welding process of hybrid laser arc welding of high nitrogen steel was simulated. The heat source model was selected and modified according to the shape of the molten pool under the actual welding condition. And then, a composite heat source model with linearly decreasing-rotational body based on logarithm curve mode and linearly increasing cylinder mode was determined. The results show that the modified heat source model can meet the actual situation in the molten pool and heat affected zone. Finally, the  correct heat source model was established.

On the basis of this model, the simulation results show that it can not only fit the width and depth of the molten pool, but also can show the movement of the molten pool. At the same time, the stress simulation results can also verify the welding law, which can provide theoretical guidance for the setting and optimization of process parameters.

Keywords  hybrid heat source  laser welding  numerical simulation

目 次

1 绪论 1

1.1奥氏体不锈钢性能 1

1.2激光复合焊接的现状 1

1.3激光复合热源焊接的数值模拟现状 4

1.4课题研究内容 5

2 复合焊接热源模型的建立 6

2.1常见焊接热源模型介绍