论文总字数：24761字

摘 要

随着工业的发展，轻量化材料受到大家的广泛关注。波纹夹层结构是一种新型的轻量化结构，在航空航天、航海、大型建筑方面具有广阔应用前景。金属波纹夹层结构是由上、下两块金属面板通过中间芯层连接而成的一种整体结构。大尺寸制备工艺是制约轻量化结构在工业与国防装备应用的关键技术，而激光穿透叠焊是实现轻量化结构大尺寸制备的有效工艺途径。T型接头作为轻量化结构的基本接头，其力学性能对波纹夹层结构的力学性能影响较大，其中疲劳性能是影响轻量化结构在工业与国防装备中长期稳定服役的关键。鉴于此，对金属波纹夹层板激光焊接T型接头疲劳性能的试验研究是至关重要的。

为了得到符合疲劳性能要求的T型接头试样焊接工艺，首先采用不同焊接功率制备单T型接头拉伸试样，进行拉伸试验，综合分析焊缝形貌、几何参数和接头强度，针对两种厚度翼板的T型接头，各自选取出一组较优焊接工艺制备疲劳试样，进行疲劳试验。试验结果表明，试样疲劳性能并未达到合格标准，主要原因是芯板与面板焊缝连接处存在间隙，以及焊缝与母材的硬度不匹配，导致应力集中程度增大，试样失效。进而对焊接工艺进行优化，通过改变焊接参数和进行焊后热处理，重新制备疲劳试样，进行疲劳试验，试验结果表明优化后焊缝在面板与芯子连接处宽度增加，焊缝、母材的硬度匹配度增加，应力集中程度减小，T型接头疲劳性能提高并达到合格标准。

关键词：Q345钢板 激光焊接 T型接头 疲劳性能

Experimental study on fatigue performance of T - joint by laser stake welding

ABSTRACT

With the development of industry, people put great emphasis on lightweight materials. Corrugated sandwich structure is a new type of lightweight structure, which has a wide application prospect in the field of aerospace, navigation and large-scale construction. The metal corrugated sandwich structure is an integral structure formed by connecting the upper and lower two metal panels through the middle core plate Large size fabrication process is a key technology that restricts the application of lightweight structure in industrial and national defense equipment. And laser stake welding is an effective way. As the basic joints of lightweight structures, T-joints have a great influence on the mechanical properties of corrugated sandwich structures. Among them, fatigue performance is the key to the long-term stable service of lightweight structures in industrial and national defense equipment. In view of this, it is very important to study the fatigue properties of laser welded T-joints of metal corrugated sandwich plate.

In order to obtain the welding process of T - joint sample which meets the requirement of fatigue performance. First, the tensile samples of single T-joints were prepared with different welding powers for tensile test. Based on the comprehensive analysis of weld morphology, geometric parameters and Strength of Welded T-Joint, a group of better welding parameters were selected to prepare fatigue samples for T-joints of two airfoil plates of different thickness. Then The fatigue test was carried out. The test results showed that the fatigue performance of the sample did not reach the qualified standard. The main reasons are the gap between the core plate and the panel and the mismatching of hardness between the welding line and the base metal , these defects lead to the increase of stress concentration and the failure of the sample eventually. Then, the welding process was optimized by changing welding parameters and conducting heat treatment after welding. The fatigue specimens were reprepared and fatigue tests were performed. The test results show that after optimization the width of the welding line between the panel and the core plate and the hardness matching degree of weld and base metal increases. The stress concentration degree of welding line is reduced, the fatigue performance of T-joint is improved and reaches the qualified standard.

Key Words：Q345; laser welding; T-joint; fatigue performance

目 录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1 金属波纹夹层结构研究现状 1

1.2 激光焊接工艺对焊缝成形的影响 2

1.3 焊接接头疲劳性能研究现状 3

1.4 本课题的研究内容和方法 4

1.4.1 本课题研究的内容 4

1.4.2 本课题研究的方法 5

第二章 试验目的、设备与试样制备 6

2.1 试验材料与设备 6

2.1.1 试验材料 6

2.1.2 试验设备 6

2.2 试验目的与试样制备 9

2.2.1 试验目的 9

2.2.2母材处理 9

2.2.3 激光焊接T型接头试样制备 9

2.2.4 金相试样、显微硬度试样制备 11

2.2.5 拉伸、拉伸疲劳试样制备 12

2.2.6 双剪、双剪疲劳试样制备 13

2.3 本章小结 13

第三章 多道焊接工艺参数对T型接头疲劳性能的影响 15

3.1 疲劳试验焊接工艺参数确定 15

3.1.1 焊缝形貌及截面几何参数 15

3.1.2 T型接头拉伸试验 17

3.2 T型接头疲劳试验 19

3.3 本章小结 21

第四章 多道焊接工艺改进 23

4.1疲劳试样制备 23

4.1.1 工艺改进 23

4.1.2 T型接头制备试样 26

4.2 疲劳试验 26

4.3 经济性分析 28

4.4 本章小结 28

第五章 结论 30

参考文献 31

致谢 35

第一章 绪论

1.1 金属波纹夹层结构研究现状

随着工业的发展，全球气候变暖，资源匮乏，能源短缺，面临这一系列的社会性难题，节能和环保被越来越多的企业重视，建立资源节约型和环境友好型社会成为时代迫切需求，各国也逐渐将可持续发展列入国策。因此，轻量化的研究理念显得尤为重要。金属波纹夹层结构是一种新型轻质结构，除了具有高比刚度、高比强度外，还在节约空间、降噪、耐火等方面具有优越性，因此金属波纹夹层结构近十多年来在国内外得到迅速发展^[1]。

请支付后下载全文，论文总字数：24761字